US20130321400A1 - 3D Map Views for 3D Maps - Google Patents

3D Map Views for 3D Maps Download PDF

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US20130321400A1
US20130321400A1 US13/632,036 US201213632036A US2013321400A1 US 20130321400 A1 US20130321400 A1 US 20130321400A1 US 201213632036 A US201213632036 A US 201213632036A US 2013321400 A1 US2013321400 A1 US 2013321400A1
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United States
Prior art keywords
map
embodiments
road
3d
3d map
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Abandoned
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US13/632,036
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Marcel van Os
Aroon Pahwa
Christopher D. Moore
Christopher Blumenberg
Patrick S. Piemonte
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Apple Inc
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Apple Inc
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Priority to US201261656043P priority
Priority to US201261656032P priority
Priority to US201261657880P priority
Priority to US201261657864P priority
Priority to US201261699855P priority
Priority to US201261699851P priority
Priority to US201261699862P priority
Application filed by Apple Inc filed Critical Apple Inc
Priority to US13/632,036 priority patent/US20130321400A1/en
Assigned to APPLE INC. reassignment APPLE INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: PAHWA, Aroon, VAN OS, MARCEL, BLUMENBERG, CHRISTOPHER, MOORE, CHRISTOPHER D., PIEMONTE, PATRICK S.
Priority claimed from PCT/US2013/043802 external-priority patent/WO2013184533A2/en
Publication of US20130321400A1 publication Critical patent/US20130321400A1/en
Application status is Abandoned legal-status Critical

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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01CMEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
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    • G01C21/26Navigation; Navigational instruments not provided for in preceding groups G01C1/00-G01C19/00 specially adapted for navigation in a road network
    • G01C21/34Route searching; Route guidance
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    • G01CMEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
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    • G01C21/26Navigation; Navigational instruments not provided for in preceding groups G01C1/00-G01C19/00 specially adapted for navigation in a road network
    • GPHYSICS
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    • G01CMEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C21/00Navigation; Navigational instruments not provided for in preceding groups G01C1/00-G01C19/00
    • G01C21/26Navigation; Navigational instruments not provided for in preceding groups G01C1/00-G01C19/00 specially adapted for navigation in a road network
    • G01C21/34Route searching; Route guidance
    • G01C21/36Input/output arrangements for on-board computers
    • G01C21/3626Details of the output of route guidance instructions
    • G01C21/3635Guidance using 3D or perspective road maps
    • G01C21/3638Guidance using 3D or perspective road maps including 3D objects and buildings
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01CMEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C21/00Navigation; Navigational instruments not provided for in preceding groups G01C1/00-G01C19/00
    • G01C21/26Navigation; Navigational instruments not provided for in preceding groups G01C1/00-G01C19/00 specially adapted for navigation in a road network
    • G01C21/28Navigation; Navigational instruments not provided for in preceding groups G01C1/00-G01C19/00 specially adapted for navigation in a road network with correlation of data from several navigational instruments
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    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02DCLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THIR OWN ENERGY USE
    • Y02D70/00Techniques for reducing energy consumption in wireless communication networks
    • Y02D70/10Techniques for reducing energy consumption in wireless communication networks according to the Radio Access Technology [RAT]

Abstract

Some embodiments provide a non-transitory machine-readable medium that stores a program which when executed on a device by at least one processing unit provides different viewing modes for viewing a three-dimensional (3D) map. The program renders a first view of the 3D map for display in a first viewing mode based on a first set of map data. The program receives input to adjust the view of the 3D map. In response to the input, the program renders a second view of the 3D map for display in a second viewing mode based on a second set of map data different from the first set of map data.

Description

    CLAIM OF BENEFIT TO PRIOR APPLICATIONS
  • This application claims the benefit of U.S. Provisional Application 61/655,997, entitled “Route Navigating Method and Apparatus”, filed Jun. 5, 2012; U.S. Provisional Application 61/656,032, entitled “Camera Animation During Navigation”, filed Jun. 6, 2012. U.S. Provisional Application 61/656,043, entitled “Camera Animation During Navigation”, filed Jun. 6, 2012; U.S. Provisional Application 61/657,864, entitled “Route Navigating Method and Apparatus”, filed Jun. 10, 2012; U.S. Provisional Application 61/657,880, entitled “Generating and Presenting Immersive and Non-Immersive 3D Map Presentations for Browsing and Navigation”, filed Jun. 10, 2012; U.S. Provisional Application 61/699,855, entitled “Rendering Maps”, filed Sep. 11, 2012; U.S. Provisional Application 61/699,851, entitled “Voice Instructions During Navigation”, filed Sep. 11, 2012; and U.S. Provisional Application 61/699,862, entitled “Generating Map Data for Rendering”, filed Sep. 11, 2012. U.S. Applications 61/655,997, 61/656,032, 61/656,043, 61/657,864, 61/657,880, 61/699,855, 61/699,851, and 61/699,862 are incorporated herein by reference.
  • BACKGROUND
  • Many map-based applications are available today are designed for a variety of different devices (e.g., desktops, laptops, tablet devices, smartphones, handheld global positioning system (GPS) receivers, etc.) and for various different purposes (e.g., navigation, browsing, sports, etc.). Most of these applications generate displays of a map based on map data that describes the relative location of streets, highways, points of interest, etc. in the map.
  • The maps used in such applications are usually two-dimensional (2D) maps or three-dimensional (3D) maps. However, a large number of the applications use 2D maps due in part to the processing-intensive demands of viewing 3D maps. For the same reason, the applications that use 3D maps are often slow, inefficient, plain, and/or simple, to the point that renders the application useless.
  • BRIEF SUMMARY
  • Some embodiments of the invention provide novel methods for generating and presenting immersive and non-immersive 3D map presentations for browsing and navigation. In some embodiments, the immersive and non-immersive 3D map presentations can be alternatively and/or sequentially displayed on a device (e.g., a mobile device) that has a touch-sensitive screen and a multi-touch interface that allow a user to interact with the presentations through touch and gestural inputs on the screen. In other embodiments, the presentations are provided on a device that does not have a touch-sensitive screen.
  • In some embodiments described below, these 3D presentations are provided by an integrated mapping application that provides several useful modalities, such as location browsing, map searching, route identifying, and route navigation operations. However, in other embodiments, the mapping application does not employ all of these modalities. For instance, in some embodiments, the mapping application does not provide route navigation.
  • In order to display immersive and non-immersive 3D map presentations, some embodiments have to generate a variety of tiles for client devices to render to generate roads, building, and surrounding scenery. In some embodiments, examples of such tiles include road and building tiles used for non-immersive 3D presentations, and navigation and building tiles used for immersive 3D presentations.
  • Before generating these tiles, a set of servers has to generate the description of the road, building, and other geometries that are placed in each of the tiles. This task involves multiple sub-tasks such as (1) receiving map data from a variety of vendors, (2) processing such data to produce one dimensional (1D) roads, (3) smoothing the 1D road graphs, (4) defining data to specify junctions, (5) generating 2D road geometries and land cover, (6) smoothing the 2D road geometries, (7) generating data (e.g., estimated height data) regarding buildings, (8) using such data to define building geometries, (9) constructing road geometries details (such as islands, lane markings, and distances and land cover between road geometries), and (10) identifying geometry edge node characteristics and propagating such characteristics.
  • Once generated on the mapping service side, the tiles are used by a mapping application on a client device to present 3D maps to users of the client devices. The mapping application of some embodiments uses a variety of novel techniques to present a 3D presentation of a map while the map is being browsed or while the map is providing a navigation presentation. For instance, the mapping application renders the 3D presentation from the vantage point of a virtual camera, and uses various methods for moving the virtual camera (i.e., moving the perspective rendering position) automatically in certain situations to achieve a desired 3D presentation. One such example occurs when the mapping application of some embodiments moves the position of the virtual camera from a perspective rendering position behind a current position of a moving device to a top-down view of the current position when the device is about to make a turn along a route. Another example is the zoom in/out animations that are provided, which show objects in the scene growing and shrinking with the zoom in operation and the zoom out operation.
  • Also, in some embodiments, the mapping application provides two different types of 3D presentations—an immersive 3D presentation and a non-immersive 3D presentation. The immersive presentation in some embodiments not only displays more geometries but also displays more details for the geometries that are displayed in the non-immersive presentation. The mapping application also provides smooth transitions between the non-immersive and immersive presentations.
  • To achieve such smooth transitions and generate other novel effects, the mapping application of some embodiments uses a novel image processing pipeline. This pipeline performs a variety of pre-load operations to download, retrieve and/or decompress map tiles that may be needed for a navigation presentation, to prepare its rendering pipeline for its rendering operations, and to prepare a duplicate pipeline to smoothly transition between the immersive and non-immersive 3D presentations.
  • The preceding Summary is intended to serve as a brief introduction to some embodiments of the invention. It is not meant to be an introduction or overview of all inventive subject matter disclosed in this document. The Detailed Description that follows and the Drawings that are referred to in the Detailed Description will further describe the embodiments described in the Summary as well as other embodiments. Accordingly, to understand all the embodiments described by this document, a full review of the Summary, Detailed Description and the Drawings is needed. Moreover, the claimed subject matters are not to be limited by the illustrative details in the Summary, Detailed Description and the Drawings, but rather are to be defined by the appended claims, because the claimed subject matters can be embodied in other specific forms without departing from the spirit of the subject matters.
  • BRIEF DESCRIPTION OF THE FIGURES
  • The novel features of the invention are set forth in the appended claims. However, for purposes of explanation, several embodiments of the invention are set forth in the following figures.
  • FIG. 1 illustrates an example of a device that executes an integrated mapping application of some embodiments of the invention.
  • FIG. 2 illustrates how the navigation application of some embodiments provides a 3D control as a quick mechanism of entering a 3D navigating mode.
  • FIG. 3 presents a simplified example to illustrate the concept of a virtual camera.
  • FIG. 4 illustrates the adjustment of the distance of a virtual camera by contracting and expanding gestures.
  • FIG. 5 illustrates an embodiment of a camera the angle of which can be adjusted by gestures.
  • FIG. 6 conceptually illustrates the mapping service processing of some embodiments.
  • FIG. 7 conceptually illustrates a process of some embodiments for generating a road graph.
  • FIG. 8 illustrates various data structures of some embodiments for the roads within a map region.
  • FIG. 9 illustrates an example of a modification for two road segments that meet at a junction.
  • FIG. 10 illustrates an example of three road segments that are candidates for aggregation into a road at a junction.
  • FIG. 11 illustrates a situation in which a first road segment is intersected (in a plane) by a second road segment and a third road segment.
  • FIG. 12 illustrates two road segments that are a distance X apart, run parallel in opposite directions, and have the same name.
  • FIGS. 13 and 14 illustrate similarly kinked roads that have speed limits of 25 mph and 60 mph.
  • FIG. 15 conceptually illustrates a process of some embodiments for generating the road geometry to be used for generating road polygons on the client mapping application.
  • FIG. 16 illustrates an operation performed to smooth a lane expansion junction in which one of the sides of the roads stays straight (i.e., is “justified”).
  • FIG. 17 illustrates the result of the smoothed lane expansion from FIG. 16 as rendered by a client mapping application of some embodiments.
  • FIG. 18 illustrates an operation performed to smooth a lane expansion junction in which the road expands at both sides.
  • FIG. 19 illustrates the result of the smoothed lane expansion from FIG. 18 as rendered by a client mapping application of some embodiments.
  • FIG. 20 illustrates a tapering operation performed to smooth a corner between road segment geometries when the angle between the segments is greater than a first threshold angle.
  • FIG. 21 illustrates the result of the smoothed junction from FIG. 20 as rendered by a client mapping application of some embodiments.
  • FIG. 22 illustrates a projection operation performed to smooth a corner between road segment geometries when the angle between the segments is less than a first threshold angle and greater than a second threshold angle.
  • FIG. 23 illustrates the result of the smoothed junction from FIG. 22 as rendered by a client mapping application of some embodiments.
  • FIG. 24 illustrates a clipping operation performed to eliminate excess road for road segment geometries when the angle between the segments is less than a first threshold angle and greater than a second threshold angle.
  • FIG. 25 illustrates an intersection operation performed to smooth a corner between two road segment geometries.
  • FIG. 26 illustrates the result of the smoothed junction from FIGS. 24 and 25 as rendered by a client mapping application of some embodiments.
  • FIG. 27 illustrates a tapering operation performed to smooth a corner between road segment geometries in situations that fit characteristics of freeway on-ramps in some embodiments.
  • FIG. 28 illustrates the result of the smoothed freeway merge junction from FIG. 27 as rendered by a client mapping application of some embodiments.
  • FIG. 29 illustrates the generation of additional geometries at a junction in order to create more realistic, rounded corners at the junction.
  • FIG. 30 illustrates the result of the smoothed intersection from FIG. 29 as rendered by a client mapping application of some embodiments.
  • FIG. 31 illustrates pushing two roads apart when they overlap.
  • FIG. 32 illustrates reducing the widths of two road segments when the road segments overlap.
  • FIGS. 33 and 34 illustrate dual carriageways with two different types of medians.
  • FIG. 35 illustrates an example of geometries for a junction of two major arterial roads.
  • FIG. 36 illustrates the result of the junction from FIG. 35 as rendered by a client mapping application of some embodiments.
  • FIG. 37 illustrates an example of the use of vertex annotation to specify bridge casing for an overpass, where one road travels over another road and the roads do not form a junction.
  • FIG. 38 illustrates the result of the road segments of FIG. 37 as rendered by a client mapping application of some embodiments.
  • FIG. 39 illustrates an example of the use of vertex annotation to specify an edge of a road segment geometry as an interior edge, indicating that no casing should be drawn for the directed edge from the annotated vertex.
  • FIG. 40 illustrates the result of the road segments of FIG. 39 as rendered by a client mapping application of some embodiments.
  • FIG. 41 illustrates an example of the use of vertex annotation to specify a tunnel for a road segment, indicating that the tunnel should be drawn over the road segment.
  • FIG. 42 illustrates the result of the road segments of FIG. 41 as rendered by a client mapping application of some embodiments.
  • FIG. 43 illustrates an example of the use of vertex annotation to specify a sidewalk for a side of a road segment.
  • FIG. 44 illustrates the result of the road segment of FIG. 43 as rendered by a client mapping application of some embodiments.
  • FIG. 45 illustrates an example of the use of several annotations for a single vertex of some embodiments.
  • FIG. 46 illustrates the result of the road segments of FIG. 45 as rendered by a client mapping application of some embodiments.
  • FIG. 47 illustrates an example of using vertex annotation data to vary a property of the road casing for a road geometry.
  • FIG. 48 illustrates the result of the road segment of FIG. 47 as rendered by a client mapping application of some embodiments.
  • FIG. 49 conceptually illustrates an operation performed by a mapping service of some embodiments to generate a route for a requesting device and provide the route, with navigation instructions, to the requesting device.
  • FIG. 50 conceptually illustrates a process performed by the mapping service of some embodiments in order to generate and transmit route and intersection data to a user.
  • FIG. 51 conceptually illustrates a process of some embodiments for determining path segments between sets of junctions that should be treated together as single intersections.
  • FIG. 52 illustrates an example of a junction of some embodiments and shows that there is no requirement that the path segments meet at right angles or that the paths continue in a straight line through the junction.
  • FIG. 53 illustrates an intersection of some embodiments that includes two dual carriageway paths and a one-way road.
  • FIG. 54 conceptually illustrates a process of some embodiments for linking together several junctions into a single intersection and identifying the branches of the intersection.
  • FIG. 55 illustrates a commonly existing intersection of some embodiments, between a dual carriageway with two paths and a dual carriageway with two paths.
  • FIG. 56 illustrates an intersection of some embodiments in which left-turn channels are defined as separate path segments.
  • FIG. 57 illustrates a slip road in an intersection of some embodiments.
  • FIG. 58 illustrates an intersection of some embodiments with both a slip road and left-turn channels.
  • FIG. 59 illustrates an additional two-way path in an intersection in some embodiments.
  • FIG. 60 illustrates the reduction of an eight-path intersection into four branches in some embodiments.
  • FIG. 61 illustrates the reduction of a different eight-path intersection into five branches in some embodiments.
  • FIG. 62 conceptually illustrates an example of a data structure of some embodiments for a point type intersection.
  • FIG. 63 conceptually illustrates a data structure of some embodiments for a roundabout intersection.
  • FIG. 64 conceptually illustrates the reduction of a roundabout intersection to intersection data in some embodiments.
  • FIG. 65 conceptually illustrates a process of some embodiments for modifying intersection data in order to provide navigation information for a route.
  • FIG. 66 illustrates a conceptual drawing of a route taken through an intersection, a data structure for the intersection, and the modification of the data structure to create a new data structure for turn-by-turn navigation instructions.
  • FIG. 67 conceptually illustrates a process performed by some embodiments of the invention perform for conflating land cover polygons to road polygons.
  • FIG. 68 illustrates one example of conflating land covers to road polygons.
  • FIG. 69 conceptually illustrates a process that conflates boundaries between adjacent polygons received from two different sources in some embodiments.
  • FIG. 70 illustrates two stages of some embodiments of the invention that resolve identified gaps by conflating boundary coordinates between adjacent polygons.
  • FIG. 71 illustrates two stages of some embodiments of the invention that conflate the boundary coordinates of polygons around identified overlaps.
  • FIG. 72 conceptually illustrates a process performed by some embodiments of the invention for resolving border conflicts between regions.
  • FIG. 73 illustrates an example of resolving a border conflict between two adjacent regions.
  • FIG. 74 conceptually illustrates an example of a virtual camera automatedly moving around a region of a 3D map based on a route navigation according to some embodiments of the invention.
  • FIG. 75 conceptually illustrates a process of some embodiments for animating map views during a route navigation.
  • FIG. 76 conceptually illustrates an example of a virtual camera automatedly maneuvering a turn in a 3D map during on a route navigation according to some embodiments of the invention.
  • FIG. 77 conceptually illustrates a process of some embodiments for animating a map view during a turn of a route navigation.
  • FIG. 78 conceptually illustrates an example of a virtual camera panning around a 3D map during a route navigation according to some embodiments of the invention.
  • FIG. 79 conceptually illustrates a process of some embodiments for panning to the side of a map view based on gesture input.
  • FIG. 80 conceptually illustrates a perspective adjustment feature provided by a mapping application of some embodiments.
  • FIG. 81 conceptually illustrates a process of some embodiments for adjusting the position of a virtual camera that is used for rendering a map view in response to a perspective adjustment.
  • FIG. 82 conceptually illustrates a virtual camera that is moveable along different arcs at different zoom levels according to some embodiments of the invention.
  • FIG. 83 conceptually illustrates a process of some embodiments for determining an arc along which a virtual camera is movable.
  • FIG. 84 conceptually illustrates a feature provided by the mapping application of some embodiments for maintaining the position of a virtual camera within a defined range along an arc.
  • FIG. 85 illustrates a zoom adjustment feature provided by the mapping application of some embodiments.
  • FIG. 86 conceptually illustrates a process of some embodiments adjusting the position of a virtual camera that is used for rendering a map view in response to a zoom level adjustment.
  • FIG. 87 conceptually illustrates a rotation operation of a 3D map view according to some embodiments of the invention.
  • FIG. 88 conceptually illustrates a rotation operation of a 3D map view after an activation of a position indicator feature according to some embodiments of the invention.
  • FIG. 89 conceptually illustrates a rotation operation of a 3D map view from a 2D perspective view of the 3D map according to some embodiments of the invention.
  • FIG. 90 conceptually illustrates a process of some embodiments for rotating a map view based on gesture input.
  • FIG. 91 conceptually illustrates an example of a mapping application of some embodiments that renders 3D map views for different zoom levels of different viewing modes.
  • FIG. 92 illustrates the movement of the virtual camera around the region of a 3D map defined to be viewed by an immersive viewing mode of some embodiments.
  • FIG. 93 illustrates the movement of the virtual camera around the region of a 3D map defined to be viewed by a non-immersive viewing mode of some embodiments.
  • FIG. 94 conceptually illustrates an example of a mapping application of some embodiments that renders 3D map views for different zoom levels of different viewing modes.
  • FIG. 95 conceptually illustrates a processing pipeline performed by the mapping application of some embodiments for rendering 3D map views based on different 3D map tiles.
  • FIG. 96 conceptually illustrates a data structure used by the processing pipeline of some embodiments.
  • FIG. 97 conceptually illustrates a state diagram of a mapping application of some embodiments.
  • FIG. 98 conceptually illustrates a processing pipeline performed by the mapping application of some embodiments in order to render a map for display at the client device.
  • FIG. 99 illustrates the application of different textures to different types of roads for some embodiments.
  • FIG. 100 illustrates a map presentation that includes one arterial road and two connector roads.
  • FIG. 101 illustrates a non-immersive map presentation illustrating the rendering of roads in a map tile, in map browsing view.
  • FIG. 102 conceptually illustrates a controller that instantiates two virtual cameras for two different views of map regions.
  • FIG. 103 conceptually illustrates a process of some embodiments for pre-loading navigation tiles to enter navigation.
  • FIG. 104 illustrates a device that displays a mapping application as the application transitions from a non-immersive map view for map browsing into an immersive map view for navigation.
  • FIGS. 105A-105B conceptually illustrate a state diagram 10500 that describes different states and transitions between these states of the integrated mapping, search, and navigation application of some embodiments.
  • FIG. 106 is an example of an architecture of a mobile computing device.
  • FIG. 107 conceptually illustrates an example of an electronic system with which some embodiments of the invention are implemented.
  • FIG. 108 illustrates a map service operating environment, according to some embodiments.
  • DETAILED DESCRIPTION
  • Some embodiments of the invention provide novel methods for generating and presenting immersive and non-immersive 3D map presentations for browsing and navigation. In some embodiments, the immersive and non-immersive 3D map presentations can be alternatively and/or sequentially displayed on a device (e.g., a mobile device) that has a touch-sensitive screen and a multi-touch interface that allow a user to interact with the presentations through touch and gestural inputs on the screen. In other embodiments, the presentations are provided on a device that does not have a touch-sensitive screen.
  • In some embodiments described below, these 3D presentations are provided by an integrated mapping application that provides several useful modalities, such as location browsing, map searching, route identifying, and route navigation operations. However, in other embodiments, the mapping application does not employ all of these modalities. For instance, in some embodiments, the mapping application does not provide route navigation.
  • In order to display immersive and non-immersive 3D map presentations, some embodiments have to generate a variety of tiles for client devices to render to generate roads, building, and surrounding scenery. In some embodiments, examples of such tiles include road and building tiles used for non-immersive 3D presentations, and navigation and building tiles used for immersive 3D presentations.
  • Before generating these tiles, a set of servers has to generate the description of the road, building, and other geometries that are placed in each of the tiles. This task involves multiple sub-tasks such as (1) receiving map data from a variety of vendors, (2) processing such data to produce one dimensional (1D) roads, (3) smoothing the 1D road graphs, (4) defining data to specify junctions, (5) generating 2D road geometries and land cover, (6) smoothing the 2D road geometries, (7) generating data (e.g., estimated height data) regarding buildings, (8) using such data to define building geometries, (9) constructing road geometries details (such as islands, lane markings, and distances and land cover between road geometries), and (10) identifying geometry edge node characteristics and propagating such characteristics.
  • Once generated on the mapping service side, the tiles are used by a mapping application on a client device to present 3D maps to users of the client devices. The mapping application of some embodiments uses a variety of novel techniques to present a 3D presentation of a map while the map is being browsed or while the map is providing a navigation presentation. For instance, the mapping application renders the 3D presentation from the vantage point of a virtual camera, and uses various methods for moving the virtual camera (i.e., moving the perspective rendering position) automatically in certain situations to achieve a desired 3D presentation. One such example occurs when the mapping application of some embodiments moves the position of the virtual camera from a perspective rendering position behind a current position of a moving device to a top-down view of the current position when the device is about to make a turn along a route. Another example is the zoom in/out animations that are provided, which show objects in the scene growing and shrinking with the zoom in operation and the zoom out operation.
  • Also, in some embodiments, the mapping application provides two different types of 3D presentations—an immersive 3D presentation and a non-immersive 3D presentation. The immersive presentation in some embodiments not only displays more geometries but also displays more details for the geometries that are displayed in the non-immersive presentation. The mapping application also provides smooth transitions between the non-immersive and immersive presentations.
  • To achieve such smooth transitions and generate other novel effects, the mapping application of some embodiments uses a novel image processing pipeline. This pipeline performs a variety of pre-load operations to download, retrieve and/or decompress map tiles that may be needed for a navigation presentation, to prepare its rendering pipeline for its rendering operations, and to prepare a duplicate pipeline to smoothly transition between the immersive and non-immersive 3D presentations.
  • Section I below describes the mapping application of some embodiments of the invention. Section II then describes server side operations for generating the tiles needed to produce immersive and non-immersive 3D presentations. Section III then describes client side operations for generating immersive and non-immersive 3D presentations. Section IV then describes electronic devices that employ the mapping application of some embodiments. Section V lastly describes location services uses by some embodiments of the invention.
  • In the following detailed description of the invention, numerous details, examples, and embodiments of the invention are set forth and described. However, it will be clear and apparent to one skilled in the art that the invention is not limited to the embodiments set forth and that the invention may be practiced without some of the specific details and examples discussed.
  • I. Navigation User Interface
  • A. Start
  • The navigation application of some embodiments is part of an integrated mapping application that includes several useful modalities, including location browsing, map searching, route identifying and route navigating operations. This integrated application (referred to below as the mapping application, the navigation application or the integrated application) in some embodiments is defined to be executed by a device that has a touch-sensitive screen that displays the output of the application. In some embodiments, this device has a multi-touch interface for allowing a user to provide touch and gestural inputs through the screen to interact with the application. Examples of such devices are smartphones (e.g., iPhone® sold by Apple Inc., phones operating the Android® operating system, phones operating the Windows 8® operating system, etc.).
  • FIG. 1 illustrates an example of a device 100 that executes an integrated mapping application of some embodiments of the invention. This figure also illustrates an example of launching a route navigation in this application. This application has a novel user interface (UI) design that seamlessly and cohesively integrates the controls for each of its different modalities by using a minimum set of on-screen controls that float on top of the content in order to display as much of the content as possible. Additionally, this cluster adapts to the task at hand, adjusting its contents in an animated fashion when a user moves between the different modalities (e.g., between browsing, searching, routing and navigating). This common element with an adaptive nature enables the mapping application to optimize for different tasks while maintaining a consistent look and interaction model while moving between those tasks.
  • FIG. 1 shows six stages 105, 110, 115, 117, 119, 121 of interaction with the mapping application. The first stage 105 shows a device's UI 120, which includes several icons of several applications in a dock area 125 and on a page of the UI. One of the icons on this page is the icon for the mapping application 130. The first stage shows a user's selection of the mapping application through touch contact with the device's screen at the location of this application on the screen.
  • The second stage 110 shows the device after the mapping application has opened. As shown in this stage, the mapping application's UI has a starting page that in some embodiments (1) displays a map of the current location of the device, and (2) several UI controls arranged in a top bar 140, and as floating controls. As shown in FIG. 1, the floating controls include an indicator 145, a 3D control 150, and a page curl control 155, while the top bar 140 includes a direction control 160, a search field 165, and a bookmark control 170.
  • In some embodiments, a user can initiate a search by tapping in the search field 165. This directs the application to present an animation that (1) presents an on-screen keyboard and (2) opens a search table full of invaluable completions. This table has some important subtleties. When the search field is tapped and before the terms are edited, or when the search field is empty, the table contains a list of “recents,” which in some embodiments are recent searches and route directions that the user has requested. This makes it very easy to quickly bring up recently accessed results.
  • After any edit in the search field, the table is filled with search completions both from local sources (e.g., bookmarks, contacts, recent searches, recent route directions, etc.) and remote servers. The incorporation of the user's contact card into the search interface adds additional flexibility to the design. When showing recents, a route from the current location to the user's home is always offered in some embodiments, while it is offered in the contexts that are deemed to be “appropriate” in other embodiments. Also, when the search term matches at least part of an address label (e.g. ‘Wo’ or ‘ork’ for ‘Work’), the application presents the user's labeled address as a completion in the search table in some embodiments. Together these behaviors make the search UI a very powerful way to get results onto a map from a variety of sources. In addition to allowing a user to initiate a search, the presence of the text field in the primary map view in some embodiments also allows users to see the query corresponding to search results on the map and to remove those search results by clearing the query.
  • The bookmark control 170 (e.g., button) allows locations and routes to be bookmarked by the application. The position indicator 145 allows the current position of the device to be specifically noted on the map. Once this indicator is selected once, the application maintains the current position of the device in the center of the map. In some embodiments, it can also identify the direction to which the device currently points.
  • The 3D control 150 is a control for viewing a map or inspecting a route in three dimensions (3D). The mapping application provides the 3D control as a quick mechanism of getting into and out of 3D. This control also serves as (1) an indicator that the current view is a 3D view, (2) an indicator that a 3D perspective is available for a given map view (e.g., a map view that is zoomed out might not have a 3D view available), (3) an indicator that a 3D perspective is not available (e.g., the 3D data is not available for the map region), and (4) an indicator that a flyover animation is available at the given zoom level. The 3D control may provide a different appearance corresponding to each indication. For instance, the 3D control may be colored grey when the 3D view is unavailable, black when the 3D view is available but the map is in the 2D view, and blue when the map is in the 3D view. In some embodiments, the 3D control changes to an image of a building when the flyover animation is available for the user's given zoom level and location on the map.
  • The page curl control 155 is a control that allows the application to minimize the number of on-screen controls, by placing certain less frequently used actions in a secondary UI screen that is accessible through the “page curl” control that is displayed on the map. In some embodiments, the page curl is permanently displayed on at least some of the map views that the application provides. For instance, in some embodiments, the application displays the page curl permanently on the starting page (illustrated in second stage 110) that it provides for allowing a user to browse or search a location or to identify a route.
  • The direction control 160 opens a direction entry page 180 through which a user can request a route to be identified between a starting location and an ending location. The third stage 115 of FIG. 1 illustrates that the selection of the direction control 160 opens the direction entry page 180, which is shown in the fourth stage 117. The direction control is one of three mechanisms through which the mapping application can be directed to identify and display a route between two locations; the two other mechanisms are (1) a control in an information banner that is displayed for a selected item in the map, and (2) recent routes identified by the device that are displayed in the search field 165. Accordingly, the information banner control and the search field 165 are two UI tools that the application employs to make the transition between the different modalities seamless.
  • The fourth stage 117 shows that the direction entry page 180 includes starting and ending fields for providing starting and ending locations for a route, and a table that lists recent routes that the application has provided to the user. Other controls on this page are controls for starting a route, for reversing the order of the start and end locations, for canceling the direction request, and for picking walking, auto, or public transit routes. These controls and other aspects of the mapping application are described in U.S. Provisional Patent Application 61/656,080, entitled “Integrated Location Browsing, Map Searching, Route Identifying, and Route Navigating Application”, filed Jun. 6, 2012; U.S. Provisional Patent Application 61/699,841, entitled “Problem Reporting”, filed Sep. 11, 2012; and concurrently filed U.S. patent application Ser. No. ______, entitled “Problem Reporting in Maps”, having Attorney Docket No. APLE.P0423. The Provisional Applications 61/656,080 and 61/699,841, as well as the concurrently filed patent application mentioned above, are incorporated herein by reference.
  • The fourth stage illustrates the user selecting one of the recent directions that was auto-populated in the table 182. The fifth stage 119 then shows three routes on a 2D map view between the specified start and end locations specified through the page 180. It also shows the selection of the second route and some information about this route in a bar at the top of the layout. This bar is shown to include start and end buttons. The start button is shown to be selected in the fifth stage.
  • As shown by the sixth stage, the selection of the start button directs the application to enter a turn-by-turn navigation mode. In this example, the application has entered a 2D turn-by-turn navigation mode. In other embodiments, the application will enter by default into a 3D turn-by-turn navigation mode. In this mode, the application displays a realistic sign 184 that identifies the distance from the current location of the device to the next maneuver in the navigated route and some other pertinent information. The application also displays a top bar that includes some information about the navigation as well as End and Overview buttons, for respectively ending the navigation and obtaining an overview of the remaining portion of the navigated route or the entire portion of the navigated route in other embodiments.
  • The mapping application of some embodiments identifies the location of the device using the coordinates (e.g., longitudinal, latitudinal, and latitudinal coordinates) in the GPS signal that the device receives at the location of the device. Alternatively or conjunctively, the mapping application uses other methods (e.g., cell tower triangulation) to compute the current location. When the user carrying the device deviates from the route, the mapping application of some embodiments tracks the location of the device and re-calculates a new route from the deviated location in order to re-direct the user to the destination location from the deviated location. In other words, the mapping application of some embodiments operating in the navigation mode requires the device to be located along a route at all times.
  • The application further displays the floating 3D control and the floating list control, which were described above. It should be noted that the list control was adaptively added to the floating control cluster upon entering the route inspection and route navigation modalities, while the position indicator was removed from the floating control upon entering the route navigation modality. Also, upon transition from the route inspection mode to the route navigation mode, the application performs an animation in some embodiments that involves the page curl uncurling completely before the application transitions into the navigation presentation.
  • In some embodiments, the animation transition includes removing the top bar, its associated controls and the floating controls from the navigation presentation, and moving the sign 184 to the top edge of the presentation a short time period after starting the navigation presentation. In some embodiments, the application requires the user to tap on the navigated map to bring back the top bar, its controls and the floating controls, and requires another tap to remove these controls again from the map. Other embodiments provide other mechanisms for viewing and removing these controls. The navigation user interface and other aspects of the navigation mode of some embodiments are described in greater detail in U.S. Provisional Patent Application 61/655,997, entitled “Route Navigating Method and Apparatus”, filed Jun. 5, 2012; U.S. Provisional Patent Application 61/657,864, entitled “Route Navigating Method and Apparatus”, filed Jun. 10, 2012; U.S. Provisional Patent Application 61/699,851, entitled “Voice Instructions During Navigation”, filed Sep. 11, 2012; and concurrently filed U.S. patent application Ser. No. ______, entitled “Context-Aware Voice Guidance”, having Attorney Docket No. APLE.P0395. The provisional applications 61/655,997, 61/657,864, and 61/699,851, as well as the above-mentioned concurrently filed patent application, are incorporated herein by reference.
  • B. 2D and 3D Navigation
  • The navigation application of some embodiments can display a map for navigation in either a 2D mode or a 3D mode. As mentioned above, one of the floating controls is the 3D control 150 that allows a user to view a navigation presentation in three dimensions (3D). FIG. 2 illustrates how the navigation application of some embodiments provides the 3D control 150 as a quick mechanism of entering a 3D navigating mode. This figure illustrates this operation in three stages 205-215. The first stage 205 illustrates the user selecting the 3D control 150 while viewing a two-dimensional navigation presentation.
  • The second stage 210 illustrates the navigation presentation in the midst of its transition into a 3D presentation. As shown in this figure, the 3D control appears highlighted at this stage to indicate that the navigation presentation has entered a 3D mode. In some embodiments, the navigation application generates the 3D view of the navigated map by rendering the map view from a particular position in the three dimensional scene that can be conceptually thought of as the position of a virtual camera that is capturing the map view. This rendering will be further described below by reference to FIG. 3.
  • The third stage 215 then illustrates the navigation presentation at the end of its transition into its 3D appearance. As shown by the difference between the heights of the buildings in the second and third stages, the transition from 2D to 3D navigation in some embodiments includes an animation that shows three dimensional objects in the navigated map becoming larger.
  • 1. Virtual Camera
  • The navigation application of some embodiments is capable of displaying navigation maps from multiple perspectives. The application can show maps in three dimensions (3D) or in two dimensions (2D). The 3D maps are generated simulations of a virtual scene as seen by a virtual camera. FIG. 3 presents a simplified example to illustrate the concept of a virtual camera 312. When rendering a 3D navigation map, a virtual camera is a conceptualization of the position in the 3D map scene from which the device renders a 3D view of the scene. FIG. 3 illustrates a location in a 3D navigation map scene 310 that includes four objects, which are two buildings and two intersecting roads. To illustrate the virtual camera concept, this figure illustrates three scenarios, each of which corresponds to a different virtual camera location (i.e., a different rendering position) and a different resulting view that is displayed on the device.
  • The first stage 301 shows the virtual camera 312 at a first position pointing downwards at an angle (e.g., a 30° angle) towards the 3D scene 310. By rendering the 3D scene from the position and angle shown in stage 301 the application generates the 3D map view 318. From this position, the camera is pointing at a location that is a moving position in front of the device. The virtual camera 312 is kept behind the current location of the device. “Behind the current location” in this case means backward along the navigation application's defined path in the opposite direction from the current direction that the device is moving in.
  • The navigation map view 318 looks as though it was shot by a camera from above and behind the device's location indicator 316. The location and angle of the virtual camera places the location indicator 316 near the bottom of the navigation map view 318. This also results in the majority of the screen being filled with the streets and buildings ahead of the present location of the device. In contrast, in some embodiments, the location indicator 316 is in the center of the screen, with half of the screen representing things ahead of the device and the other half representing things behind the device. In order to simplify the figure, no road signs are depicted for the views 318, 328, and 338.
  • The second stage 302 shows the virtual camera 312 at a different position, pointing downwards towards the scene 310 at a larger second angle (e.g., a 45° angle). The application renders the scene 310 from this angle, resulting in the 3D navigation map view 328. The buildings and the roads are smaller than their illustration in the first navigation map view 318. Once again the virtual camera 312 is above and behind the location indicator 326 in the scene 310. This again results in the location indicator appearing in the lower part of the 3D map view 328. The location and orientation of the camera also results again in the majority of the screen displaying things ahead of the car, which is what someone navigating needs to know.
  • The third stage 303 shows the virtual camera 312 at a top-down view that looks downwards on a location on a 2D map 345 that corresponds to the location in the 3D map scene 310 that was used to render the 3D views 318 and 328. The scene that is rendered from this perspective is the 2D map view 338. Unlike the 3D rendering operations of the first and second stages that in some embodiments are perspective 3D rendering operations, the rendering operation in the third stage is relatively simple as it only needs to crop a portion of the 2D map that is identified by a zoom level specified by the application or the user. Accordingly, the virtual camera characterization in this situation somewhat unnecessarily complicates the description of the operation of the application, as cropping a portion of a 2D map is not a perspective rendering operation.
  • At the third stage 303, the mapping application in some embodiments switches from rendering a 3D scene from a particular perspective direction to cropping a 2D scene when the camera switches from the 3D perspective view to a 2D top-down view. This is because in these embodiments, the application is designed to use a simplified rendering operation that is easier and that does not generate unnecessary perspective artifacts. In other embodiments, however, the mapping application uses a perspective rendering operation to render a 3D scene from a top-down virtual camera position. In these embodiments, the 2D map view that is generated is somewhat different than the map view 338 illustrated in the third stage 303, because any object that is away from the center of the view is distorted, with the distortions being greater the further the object's distance from the center of the view.
  • The virtual camera 312 moves along different trajectories in different embodiments. Two such trajectories 350 and 355 are illustrated in FIG. 3. In both these trajectories, the camera moves in an arc and rotates more downward as the camera moves upwards on the arc. The trajectory 355 differs from the trajectory 350 in that in the trajectory 355 the camera moves further away from its point of focus (and the user's current location) as it moves up the arc.
  • While moving along one of the arcs, the camera rotates to maintain a point ahead of the location indicator at the focal point of the camera. In some embodiments, the user can turn off the three dimensional view and go with a purely two dimensional view. For example, the applications of some embodiments allow a three dimensional mode to be turned on and off by use of a 3D button 360. The 3D button 360 is highly useful to the turn-by-turn navigation feature, where it has a role as an indicator and toggle. When 3D is turned off, the camera will maintain a 2D navigation experience, but when 3D is turned on, there may still be some top-down perspectives when 3D viewing angles don't make sense (e.g., when going around a corner that would be obstructed in 3D mode).
  • 2. User Adjustment of Camera Height
  • Besides (or instead of) having the navigation application control the camera (e.g., turning from 3D to 2D when going around corners) some embodiments also allow the user to adjust the level of the camera. Some embodiments allow the user to make a command gesture with two fingers to adjust the distance (height) and angle of the camera. Some embodiments even allow multiple types of gestures to control the camera. FIG. 4 illustrates the adjustment of the distance of a virtual camera by contracting and expanding gestures. The figure is shown in three stages. In stage 401, the application shows a basic scene 410 with a virtual camera 412 at the default level for 3D viewing and the screen view 414 rendered from the scene 410. The basic scene contains two buildings and a T-junction. In stage 401, the buildings are viewed from a 45 degree downward angle and a particular height that makes them seem a particular size. The location indicator 416 is also shown at a particular size.
  • In stage 402, the user makes a gesture by placing two finger tips 420 near each other on the screen of the device, on the screen view 424 and moving the fingertips apart while they are on the screen. Moving the fingertips 420 apart has the effect of making the map (both the part between the fingers and the rest of the map) larger. In order to make the things in the map appear larger, the application causes the virtual camera 412 to zoom in. In some embodiments, the line 450 along which the mapping application moves the virtual camera 412 is a line formed by the front of the virtual camera 412 and the virtual camera 412's point of focus. The mapping application of some embodiments moves the virtual camera 412 along a line formed by the front of the virtual camera 412 and a location in the 3D map 410 based on the user's input to zoom into (or out of) the view of the 3D map 410.
  • After zooming in for stage 402, the user decides to zoom out for stage 403. In this stage the user has placed two fingers 430 on the screen and brought them closer together. Bringing the fingers closer together has the effect of shrinking the map (both the part between the fingers and the rest of the map). The zoom-out adjustment is accomplished by moving the virtual camera 412 farther away from the 3D map 410 along the line 455. In some embodiments, the line 455 along which the mapping application moves the virtual camera 412 is a line formed by the front of the virtual camera 412 and the virtual camera 412's point of focus. The mapping application of some embodiments moves the virtual camera 412 along a line formed by the front of the virtual camera 412 and a location in the 3D map 410 based on the user's input to zoom into (or out of) the view of the 3D map 410.
  • Rendering a 3D map view using the virtual camera 412 at this position results in a 3D map view 434 in which the buildings and the roads appear farther than the position illustrated in the 3D map view 424. As shown by the dashed-line version of the virtual camera 412, the virtual camera 412 moved farther from the 3D map 410 along the line 455.
  • In addition to being controllable by zooming in and out, some applications allow a user to change the angle of the virtual camera. FIG. 5 illustrates an embodiment of a camera the angle of which can be adjusted by gestures. The figure is shown in three stages 501-503. In stage 501, the camera is pointing downward at 45 degrees at scene 510. Scene 510 contains two buildings and a T-junction which are shown in screen view 514. The buildings are shown from a particular angle and a particular size. The location indicator 516 is also shown at a particular size.
  • In stage 502, the user has placed two fingers 520 on the screen approximately horizontal to each other and dragged up. This has the apparent effect of dragging the scene up with the fingers. The scene rising is accomplished by the virtual camera 512 lowering and changing its viewing angle from 45 degrees to 30 degrees. In the screen view 524, the buildings and the location indicator look taller than in stage 501.
  • After the user drags the scene up in stage 502, the user then drags the scene down in stage 503. To do this, the user again places two fingers 530 on the screen and drags downwards. This drags the scene down along with the fingers 530. The scene dropping is accomplished by the virtual camera 512 rising and changing its angle with the scene 510 to 60 degrees downward. In stage 503, the camera 512 has moved farther up and is angled down more than in stage 501. Accordingly, the buildings and location identifier 536 again look even shorter and smaller in stage 503 than in stage 501.
  • In some embodiments, the mapping application provides an inertia effect for different operations (e.g. panning, rotate, entering from 2D to 3D). When a user provides a particular type of input (e.g., input that terminates at a velocity greater than a threshold velocity) to pan the 3D map, the mapping application generates an inertia effect that causes the 3D map to continue panning and decelerate to a stop. The inertia effect in some embodiments provides the user with a more realistic interaction with the 3D map that mimics behaviors in the real world.
  • The application of some embodiments allows the distance and angle of the camera to be independently controlled. For example, it allows the distance to be controlled by the contracting and expanding finger gestures and the angle to be controlled by the dragging of horizontally placed fingers. Other embodiments use whichever gesture is being performed to set either a distance or an angle of the camera, with the other variable being set automatically. While FIGS. 4 and 5 show gestures performed in a certain direction leading to certain results, in some embodiments, one or both of these gestures could be reversed. For example, in some embodiments, dragging horizontally placed fingers down may bring the camera down rather than bringing the scene down. That would have the effect of moving the scene down when the fingers move up and moving the scene up when the fingers move down.
  • II. Server Side Generation of Map Tiles
  • In order to display both immersive and non-immersive 3D map presentations, some embodiments have to generate a variety of tiles for client devices to render to generate roads, building, and surrounding scenery. In some embodiments, examples of such tiles include road and building tiles used for non-immersive 3D presentations, and navigation and building tiles used for immersive 3D presentations.
  • Before generating these tiles, a set of servers has to generate the description of the road, building, and other geometries that are placed in each of the tiles. This task involves multiple sub-tasks such as (1) receiving map data from a variety of vendors, (2) processing such data to produce one dimensional (1D) roads, (3) smoothing the 1D road graphs, (4) defining data to specify junctions, (5) generating 2D road geometries and land cover, (6) smoothing the 2D road geometries, (7) generating data (e.g., estimated height data) regarding buildings, (8) using such data to define building geometries, (9) constructing road geometries details (such as islands, lane markings, and distances and land cover between road geometries), and (10) identifying geometry edge node characteristics and propagating such characteristics.
  • The mapping service of some embodiments generates downloadable map tile data through offline processing of map data (e.g., data received from map vendors). In some embodiments, this offline processing takes map object location input (e.g., latitude/longitude data for roads, administrative boundaries, natural boundaries, etc.) and generates aggregated roads and relationships between the aggregated roads. From the aggregated roads and their relationships, the mapping service processing generates road geometries. The mapping service also generates geometries for land cover (e.g., parks, oceans, states, etc.) using the map object location input. Some embodiments use scalable distributed processing to create downloadable map tiles from the geometric vector data. One of ordinary skill in the art will recognize that the “offline” processing described in this application may be performed by mapping service computing devices that are in fact connected to the network through which the mapping application requests tile data, but is used to represent that the processing is not performed in response to user requests for tiles.
  • FIG. 6 conceptually illustrates the mapping service processing 600 of some embodiments. As mentioned, some embodiments perform this processing offline to generate various map tiles which can then be sent to client devices in response to real-time requests. The processing may be performed on a regular basis (e.g., hourly, daily, weekly) or may be performed any time new data becomes available (e.g., updates received through providers of map data, corrections received from users, etc.).
  • The mapping service processing 600 includes a 1-D road processor 605, a road geometry generator 610, a land cover geometry generator 615, a building geometry generator 617 and a tile generator 620. One of ordinary skill in the art will recognize that the various modular operations shown in FIG. 6 may all be performed on a single server or may be distributed across several computing devices. In fact, some of the operations (e.g., tile generation) may be performed as distributed processing operations that span multiple computing devices.
  • In addition to the processing operations, FIG. 6 illustrates road segment data 625, land cover data 630, and building data 633. Road segment data 625 stores data defining the location and properties of roads. In some embodiments, each road segment is assigned one or more names (e.g. “Lincoln Blvd.”, “CA-1”), location data that indicates the path of the road segment, and attributes of the road segment (e.g., speed limit, width, number of lanes, road type, etc.). In some embodiments, the locations of junctions (also referred to as junctions) is part of the road segment data. The land cover data 630 stores data defining the location and properties of various types of non-road land cover. The land cover may include bodies of water (e.g., rivers, oceans, lakes, swimming pools, etc.), administrative bodies (e.g., boundaries of states, countries, cities, parks, etc.), area designations (e.g., rural/urban/suburban, desert/mountains/forest, etc.), or other data describing the land between roads. The building data 633 of some embodiments stores the location of buildings as well as data about the buildings. For instance, the building data may include ground elevation data and surface elevation from which building height may be calculated.
  • The road segment data 625, land cover data 630, and building data 635 may be received from a single source (e.g., a single vendor of map data) or several sources (e.g., several different vendors). For instance, a first vendor might provide road data for a first region while a second vendor provides road data for a second region, a third vendor provides land cover data for the first and second regions, and a fourth vendor provides elevation data (or other combinations, such as multiple different vendors of land cover data for different types of information).
  • The 1-D road processor 605 receives road segment data 625 and generates one or more road graphs from the data. A road graph, in some embodiments, links together a set of road segments and junctions of road segments. To generate the road graph, the 1-D road processor 605 identifies road segments that should be combined into aggregate roads (i.e., based on the names, start and end points, and common attributes of the segments). For example, when the end of a first segment shares a location with the start of a second segment, the segments have at least one name in common and the segments share at least some attributes, then the road processor 605 combines the segments into an aggregate road. The 1-D road processor additionally fills in data required for additional processing (e.g., elevation data, speed limit data, number of lanes) when this is missing from the road segment data.
  • In addition to forming the aggregate roads, the 1-D road processor 605 identifies and generates angle information for junctions of the roads (e.g., as described below) and identifies other relationships between roads (e.g., merging dual carriageways, establishing overlap relationships). A connected set of junctions and segments forms a road graph.
  • The road geometry generator 610 generates geometries for the roads (i.e., sets of vertices for drawing the roads at the client devices) based on the road graph using various processes. In some embodiments, the road geometry generator 610 grows road geometries out from the road centerlines (e.g., using lane #, width, and offset data), then performs various operations to refine the geometries. As examples, the road geometry generator 610 smoothes transitions between road segments with different numbers of lanes, creates more realistic rounded corners at intersections, smoothes road merges to remove excess road pieces and gaps between roads, and removes overlap between separate roads that do not intersect. In addition, in some embodiments the road geometry generator 610 assigns specific characteristics to the polygon vertices and/or edges, such as marking tunnel entries, marking road interior edges (e.g., between segments), marking sidewalks, and marking bridge casings where shadows should be drawn.
  • The land cover geometry generator 615 uses both the land cover data 630 and road segment data 625 in some embodiments to create the geometries (i.e., sets of vertices defining polygons) for the land cover. After growing geometries for the land cover, some embodiments use various operations to resolve boundaries between the geometries. For example, when combining data from different sources, the location data indicating object boundaries may not align perfectly and therefore there may be either gaps between the object geometries or overlap of the geometries. Some embodiments use different operations for resolving boundaries between different geometries, depending on the types of objects. In addition, the land cover geometry generator 615 uses the road segment data to fill in the land cover geometry and ensure that gaps are not left between the land cover and the roads. Some embodiments grow the land cover geometries outside of their marked boundaries towards the roads, stopping the geometries at road centerline locations. While this creates an overlap between the land cover geometry and road geometry, in some embodiments the client mapping applications include instructions to render road geometry on top of land cover geometry.
  • The building geometry generator 617 of some embodiments generates building geometries using the building data 633. In some embodiments, as mentioned, the building data 633 includes ground elevation and surface elevation data, in addition to locations of the buildings. To generate building geometry, some embodiments calculate the building height for various points within the location of the building. The building geometry generator 617 retrieves the ground elevation and subtracts this from the surface elevation data to calculate the building height. In other embodiments, the building geometry generator 617 (or another module) uses 3D satellite data to calculate the height data. To calculate a height for the building as a whole, the building geometry generator 617 calculates an overall height as the mean of the various calculated heights at different points, plus a bias factor constant multiplied by the standard deviation of the point heights. The bias factor, in some embodiments, is a constant determined from ground truth (e.g., data determined at the actual location) and experiments.
  • Some embodiments also determine whether the building is flat or non-flat (e.g., with a pointy roof). When the standard deviation of the point heights is above a threshold (which may also be based on ground truth and experiments), the building geometry generator 617 designates the roof as non-flat. When the standard deviation of the point heights is below the threshold, the building geometry generator 617 designates the roof as flat. When generating the geometry vertices, some embodiments create pointy roofs (e.g., triangular prisms or pyramids) for non-flat buildings.
  • The road, land cover, and building geometries are sent to the tile generator 620. In some embodiments, the tile generator 620 creates several tiles for a map region, at different levels of detail (i.e., zoom levels). Some embodiments define the tile location boundaries for the different zoom levels (e.g., with a tile at a first zoom level containing four tiles at the next zoom level), then use distributed processing techniques to assign the different geometries (both roads and land cover) to the various tiles. After assigning the geometries to tiles (each geometry may be assigned to one or more tiles at each zoom level), the tile generator 620 uses additional distributed processing to generate and compress the tiles. In some embodiments, map tiles contain vector data describing the polygons to generate for rendering the data as a 2D or 3D map. To reduce the amount of vector data (and thereby reduce the size of the files for easier transmission), some embodiments use a transient rasterization process that reduces the vector data to raster information, then revectorizes the data with fewer vertices.
  • As shown, the tile generator 620 outputs tile data 635 to storage. The stored tile data 635 is the data accessed by client mapping applications in order for the applications to generate maps for viewing by a user. As shown, the tile data of some embodiments includes non-immersive map tiles 640, immersive map tiles 645, building tiles 650, and traffic tiles 655. The non-immersive map tiles 640 and immersive map tiles 645 provide different levels of data. In some embodiments, the mapping application includes an immersive 3D view and a non-immersive 3D view, with the immersive 3D view providing additional detail (e.g., asphalt view of roads, more realistic land cover and buildings, closer simulation of driving view, etc.). Some embodiments use separate tile sets for the different views, with the immersive map tiles 645 including a greater level of detail about the roads and land cover. In addition to the road segment and land cover data, the map tiles may contain additional data. For instance, the tiles may include various sets of label data (e.g., road labels, place labels, land cover labels, etc.). As shown, the tile data 635 also includes building tiles that indicate geometry for drawing buildings (based on the height and location information) in some embodiments, as well as traffic tiles 655 that are updated regularly with traffic information. Some embodiments use the building tiles for both the immersive and non-immersive 3D views.
  • A. Road Data and Road Graph Generation
  • As stated above, some embodiments receive road segment data (i.e., from one or more sources) and generate a road graph from the road segments. FIG. 7 conceptually illustrates a process 700 of some embodiments for generating a road graph. The process 700 will be described by reference to FIG. 8, which illustrates various data structures of some embodiments for the roads within a map region. These data structures, which will be described in greater detail below, include road segments 800, edges 805, roads 810, junctions 815, and a road graph 820.
  • As shown, the process 700 begins by receiving (at 710) a set of road segments and junctions for a map region. In some embodiments, the process 700 (or a similar road graph generation process) is run separately for different map regions (e.g., for states, rectangular geographic areas, land masses, etc.). The road segments for a map region may be received from a single source or from several different sources. In some embodiments, a road segment is a consistent stretch of road that has a single consistent set of attributes (i.e., same number of lanes, speed limit, etc.). When a road attribute changes (e.g., speed limit changes from 45 mph to 35 mph, or a lane is added), a new road segment is defined.
  • The junctions for a map region are generally received from the same source as the roads that meet at the junctions. In some embodiments, a junction defines an intersection of at least two roads—i.e., that two or more road segments not only cross the same location (which can be determined from the road segment data) but also that the road segments actually intersect each other so that a vehicle can transition from one road segment to the other at the junction.
  • FIG. 8 illustrates the data structure 800 of some embodiments for a road segment as well as the data structure 815 for a junction. As shown, the road segment includes a segment ID (i.e., a unique identification), one or more names, geometry information, and attribute information. The geometry information (which is different than the road geometries created for defining vector data) defines the path and other geometric information about a road segment. As shown, the geometry information includes centerline path data (e.g., an ordered string of coordinates that define the center of the road), start and end junction information, parameters to indicate the width and offset with respect to the centerline, and functionality enabling evaluation of the sides of the road at any point along the road segment. In some embodiments, this is a function on the road segment class that utilizes the centerline, offset, and width information to calculate the location of the sides of the road. While this diagram shows the road drawing data including start and end junctions, some embodiments do not define one as the start and one as the end, but rather simply indicate two junction IDs as endpoints (or a single junction ID if the road segment dead-ends).
  • The attribute information describes metadata about the road segment, such as the road type (or functional road class, which defines the level of importance of a road, from freeway down to pseudopath), the number of lanes, the speed limit, the relative elevation of the road (which may contain references to one or more other road segments and/or junctions, indicating that the present road segment runs below or above the referenced object), the height of the road (relevant for identifying elevation), the form of way (which defines a path as a dual carriageway, single carriageway, walkway, stairs, connector road, slip road, etc.), restrictions (e.g., toll restrictions, vehicle type restrictions, indications that a road is private, etc.).
  • In addition, as shown in FIG. 8, some embodiments define an edge 805 for each road segment. An edge data structure contains a reference (e.g., a pointer) to a road segment to which the edge corresponds, an orientation flag that indicates whether the edge is oriented in the same direction as the road segment, and a functionality to calculate the right and left sides of the edge using the width and centerline data of the referenced road segment. In some embodiments, this functionality exists as a function on the edge class. The edges, in some embodiments, are data constructs used to create the road graph. For a road segment that has both a start and end junction, some embodiments define two edges (one in each direction), so that each junction can reference an edge leading out from the junction.
  • As shown in FIG. 8, the junction data structure 815 includes a unique junction ID, an ordered list of edges with associated angles, a location, and an elevation order. While this data structure shows an edge list, some embodiments additionally include a list of road segments referred to by the segment IDs, from which the edge list is generated. In some embodiments, the junction ID, list of segment IDs, and elevation order are received from the road data source, while the angles and edge list are calculated by the mapping service. As each road segment is associated with one or more edges, the mapping service processing can determine the appropriate directed edges to list for the junction (the edges directed away from the junction). For many surface street junctions, the relative elevation is not especially meaningful, as the junction and all roads at the location will be at the same level. However, at intersections such as interchanges, or when a road segment passes under or over a freeway, the elevation order indicates which junctions are on top of other junctions and/or road segments.
  • After receiving the road segments, the process defines (at 710) a road graph for the map region from the road segments and junctions. As shown in FIG. 8, the road graph data structure 820 includes a set of road segments and a set of junctions. In some embodiments, the application traverses the edges and junctions to identify connected sets of edges, then maps these edges to the road segments. Other embodiments use the start and end junctions stored in each of the road segments, and the list of segments stored for each junction to define the connectivity of the segments and junctions. Some embodiments define a single road graph for a map region. However, some embodiments will define multiple road graphs when there are multiple connected sets that do not intersect.
  • Next, the process 700 performs (at 715) preprocessing on the road graph to align road segments at junctions. In order to identify angles of roads at junctions properly, and to generate polygon geometries for the roads, the roads intersecting at a junction should all end/start at exactly the same location. However, the road centerline for each of the segments that meet at a particular junction may not end at the exact same location in the received map data. Thus, for each junction, some embodiments calculate an average position of the segment path ends, and assign this position to the junction for its location. In addition, the mapping service processing modifies the road segment path data for each of the segments that meet at the junction so that the centerlines all end at the calculated average position.
  • FIG. 9 illustrates an example of such a modification for two road segments 905 and 910 that meet at a junction, over two stages 920 and 930. As shown, each road segment includes a start junction and an end junction, with the end junction of the first road segment 905 and the start junction of the second road segment 910 being the same (both referring to a junction with an ID of 16). However, as shown in the first stage 920, the centerline paths of the first road segment 905 and the second road segment 910 do not start/end at the same place (and, in fact, do not intersect at all). Thus, some embodiments identify the average position of the ends that should meet. For a junction with only two road segments, this location will be halfway along a line between the two path endpoints, as shown by location 915 in the figure. Each of the ending vertices of the centerlines has a pair of coordinate values (e.g., (x,y) coordinate values, or geolocation coordinates (latitude, longitude)). Some embodiments calculate an average among all of the ending vertices for each coordinate, and use this as the average location for the junction.
  • After identifying the junction location, the mapping service processing modifies the road segments so that the centerlines all end at the identified location. The second stage 930 shows one example of such a result. In some embodiments, when the road segments are received, the centerline paths may not have vertices at fixed distances. The mapping service processing of some embodiments standardizes the road segment vertices so that each vertex is at a fixed distance (e.g., 10 meters), enabling smoother (less kinked) road polygons. Some embodiments, for a particular road segment, identify a vertex a fixed distance from the end (e.g., 50 meters, 100 meters, etc.) and hold this point fixed, while modifying the other vertices between this point and the end vertex. In some embodiments, the vertices are moved by a lesser amount as they get further away from the endpoint. That is, a vector is calculated for the movement of the end vertex to the identified location, and the other vertices are moved by smaller iterations of this vector.
  • With preprocessing complete, the process combines (at 720) the road segments into aggregate roads. Some embodiments determine when road segments are in fact different portions of the same road, so that the segments can be treated as a single road for the purposes of defining a map (e.g., for generating labels) and for certain aspects of generating polygons for the roads. In some embodiments, the process uses various attribute and geometry data of the segments to determine whether two segments should be combined.
  • Some embodiments traverse the road graph to combine the road segments into aggregate roads. While traversing the graph, entering a junction from a particular road segment, the mapping service processing determines which of the other segments is a best match to be a continuation of the current road segment. Some embodiments score each of the segments and aggregate the roads in a greedy fashion.
  • To compute a score for a particular segment, the mapping service processing evaluates the difference in angle between the incoming road segment and the particular segment, the compatibility of the road segment names, and compares the road attributes. For the angle, the closer the segment is to 180° (i.e., a continuation straight through the junction), the higher the segment will generally score; typically, a road will continue straight or approximately straight through a junction, rather than turning. Some embodiments perform a fuzzy comparison between the road names associated with each segment. That is, the processing compares the string for the incoming road segment with the particular road segment using approximate string matching techniques. In some cases, one or more of the road segments may have multiple names, and the processing performs comparisons of each to find the best match or matches, and uses these best matches in computing the score (e.g., using the comparison of “San Diego Freeway South” to “San Diego Freeway South” rather than to “I-405 South”).
  • In addition, at least some of the road attributes are compared to compute the comparison score in some embodiments. For instance, the mapping service processing of some embodiments compares the road type (i.e., highway, arterial road, minor road, etc.), number of lanes, speed limit, form of way (i.e., single carriageway, dual carriageway, etc.). Once the scores are computed, some embodiments select the segment with the highest score and determine whether it is above a threshold for continuing the road. In addition, some embodiments identify the selected best road segment, and perform a comparison between the selected road segment and each of the other segments. Only if a first segment is the best match for a second segment and the second segment is the best match for the first segment does the processing aggregate the roads. This prevents an incoming road segment that actually ends at a “T” intersection from being joined with one of the road segments that actually continues through the intersection.
  • FIG. 10 illustrates an example of three road segments 1005, 1010, and 1015 that are candidates for aggregation into a road at a junction 1020. As shown, the first segment 1005 has the name “Wilshire Blvd”, a speed limit of 40 mph, and three lanes, and is an arterial road. The second segment 1010 also has the name “Wilshire Blvd” and three lanes, and is also an arterial road, but has a speed limit of 35 mph. The third segment 1015 has the name “Saltair Ave”, a speed limit of 35 mph, and 2 lanes, and is characterized as a minor road. If the initial incoming segment is the third segment 1015, then the segment 1010 would be the higher-scoring road segment of the two possible continuations. However, for the second segment 1010, the third segment 1015 will not be the optimal road continuation, as the first segment 1005 will have a much higher continuation score (the angle, road name, road type, and number of lanes are the same, and the only difference is the 5 mph in speed limit). As such, the optimal result at this junction 1020 is for the road of which the third segment 1015 is a part to terminate, with the first segment 1005 and second segment 1010 linked together as a single road. Other embodiments do not perform the reciprocity test, but instead set a high enough threshold that bad matches are unlikely. Furthermore, while traversing the road graph, some embodiments allow a segment to be moved from one aggregate road to another when a better match occurs later in the traversal (e.g., if road segment 1015 is found to continue on into road segment 1010, but then the junction 1020 is reached again via road segment 1005, the segment 1010 may be moved from the first road to a new road that also contains road segment 1005.
  • FIG. 8 illustrates a road data structure 810 of some embodiments. As shown, the road data structure 810 includes an ordered list of edges (through which the road object contains references to its constituent segments). In addition, the road structure contains functionality to evaluate the road centerline and the sides of the road at any point along the road. In some embodiments, the centerline functionality exists as a function of the road class that refers to the centerline information of the constituent segments (and may also interpolate between any slightly mismatched centerlines). The side of road functionality also exists as a function of the road class, that uses the side of road function from the road segment objects contained by the road object.
  • Returning to FIG. 7, after combining the road segments, the process 700 derives (at 725) additional road description data. In some embodiments, this involves filling in missing data in the road segment information. As some embodiments implement the road segments (and other data) as objects, in some cases the object variables will have null values because the data has not been provided by the map data provider. For instance, speed limit data, road width, number of lanes, or other parameters may be missing. Some embodiments automatically fill in values for at least some of the missing data of a road segment when possible, either using other information from the road segment or information from neighboring road segments. For example, some embodiments might fill in missing speed limit information for a road segment based on the speed limits of the neighboring segments (e.g., if a first segment has a speed limit of 55 mph and a third segment has a speed limit of 35 mph, then the middle segment could be filled in with a 45 mph speed limit).
  • Other embodiments only fill in data necessary for generating the road geometry, such as the number of lanes and road width information. For example, some embodiments may use neighboring road segments within an aggregated road to generate the number of lanes (e.g., if segments on either side of a particular segment have a particular number of lanes, that particular number of lanes may be assigned to the particular segment as well). For the road width, some embodiments use the number of lanes (if it exists) to assign a width to the road (e.g., assume that each lane is 4 meters wide). On the other hand, some embodiments assign road widths based on the road type (i.e., freeways have a first width, major arterials have a second width, etc.). In fact, some embodiments derive the number of lanes from the road type (e.g., freeways always assigned three lanes, etc.), then generate the width based on the number of lanes.
  • In addition, some embodiments fill in missing data for height, or elevation, information. As described above, in some cases the map data specifically indicates that a particular road segment passes over (or under) another road segment, or over (or under) a junction, or that a particular junction passes over (or under) another junction. However, this relative elevation data may be missing in some cases. When a first segment (or junction) and second segment (or junction) have centerline paths that intersect in a flat plane, but for which no junction is defined, then the paths must be at different elevations. When the absolute elevation data is included from the map data provider, this data can be used to ascertain the relative elevation data (i.e., defining a relationship that a first segment with lower absolute elevation passes under a second segment with a higher absolute elevation.
  • When relative elevation data cannot be ascertained for a particular set of road segments that intersect in the plane but do not meet at a junction, some embodiments create a random relative ordering for segments. In other embodiments, a likely relative ordering may be derived from road types of the non-intersecting roads, but may also use attributes of other nearby road segments. FIG. 11 illustrates a situation in which a first road segment 1105 (“I-405N”) is intersected (in a plane) by a second road segment 1110 (“Wilshire Blvd.”) and a third road segment 1115 (“Main St.”). However, in this case the map data does not indicate any junctions between these road segments. The I-405N segment has a height of 1 while the Wilshire segment has a height of 0. However, the Main St. segment has a null height (i.e., this information is not provided). Based on the fact that the I-405N segment travels over the Wilshire Blvd. segment, some embodiments also assume that the I-405N will travel over Main St. As such, the mapping service operations automatically fill in the height of the road segment data structure for Main St. with a value of 0, or will fill in a relative ordering indicating that the segment of Main St. travels under the segment of I-405N.
  • Additionally, the process 700 establishes (at 730) relationships between roads and road segments. In some embodiments, establishing relationships includes identifying semantic data, such as opposite sides of dual carriageway, and defining links between the related roads. In some embodiments, the process identifies roads containing road segments with the same or similar names (e.g., “I-5 N” and “I-5 S”), that are marked as dual carriageways (i.e., in a form of way field), and that are within a threshold distance of each other and a threshold angle of being parallel. FIG. 12 illustrates two road segments 1205 and 1210 that are a distance X apart, run parallel in opposite directions, and are both named “Main St.” Assuming that the distance X is less than the threshold distance for roads with the same name, then these roads will be linked as associated dual carriageways, and turns between the roads can be classified as U-turns rather than separate left turns. Additional semantic data that may be propagated includes assigning names to connector/slip roads (e.g., freeway entrances, freeway interchanges, right turn slip roads, etc.).
  • Lastly, the process 700 generates (at 735) a smoothed version of the roads. In some embodiments, the centerline data may have noise. For instance, a five mile stretch of freeway may in actuality be straight, but the data may have slight back and forth in places. In addition, as the roads are defined as lines between centerline vertices, kinks might appear where the road has a smooth turn in reality. Furthermore, when road segments are joined at junctions, this may create sharp turns that should be smoother in reality. As this sort of noise is unwanted, some embodiments apply a smoothing operation, controlled by road properties, to the roads (e.g., either one road segment at a time, or to aggregate roads) in the road graph. To perform the smoothing, various different operations may be performed by different embodiments. Some embodiments use smoothing operations that move each vertex in the road a distance based on the locations of its neighbor vertices (e.g., Laplacian smoothing).
  • Some embodiments allow more smoothing for faster roads, because of the expectation that these roads (e.g., freeways) will be smoother and less likely to have sharp angles. Some embodiments use the speed limit data to control the smoothing. For example, some embodiments allow different deviations of the centerline from the received vertex data for roads with different speed limits (e.g., allowing up to a 5 meter deviation for speed limit 65 roads, and a 2 meter deviation for 30 mph roads). FIG. 13 illustrates a kinked road 1310 that has a speed limit of 25 mph. The result of applying the smoothing operation to the road is illustrated as modified road 1320. FIG. 14, on the other hand, illustrates a similarly kinked road 1410 with a speed limit of 60 mph. The result of applying a similar smoothing operation to the road is illustrated as modified road 1420. As shown, the modified road 1420 illustrates a greater level of curve smoothing because the speed limit of the road is larger. Some embodiments use other properties to modify the level of smoothing allowed, such as road types (which can serve as a proxy for speed limit).
  • In addition, some embodiments limit smoothing in special cases. For instance, a road might make a 90° turn (e.g., where two roads both end at a junction in a residential neighborhood, and have been joined together). In such a case, rather than smoothing the road too much, some embodiments fix two points close to the junction (one on either side of the 90° turn) and smooth a small elbow between these two points.
  • B. Generating Road Geometry
  • After generating the road graph from road segments and junctions, aggregating roads in the road graph, filling in missing data, smoothing the aggregate roads, etc., the offline processing of the mapping service of some embodiments generates geometry for the roads in the road graph. In some embodiments, the geometry comprises a set of vertices that define the edges of polygons to be rendered by the client mapping application. These geometries are included in vector map tiles that are sent to devices running mapping applications in order for the mapping applications to render the resultant polygons. The mapping service processing initially bases the geometry off of the road segment definitions (i.e., the centerline vertices and width data), but also performs various adjustment operations on the geometry, such as smoothing the polygons to create more realistic rendered roads and intersections, eliminating overlaps, and annotating vertices with data that marks features to draw (e.g., shadows, bridge casings, curbs, sidewalks, tunnels, etc.).
  • FIG. 15 conceptually illustrates a process 1500 of some embodiments for generating the road geometry to be used for generating road polygons on the client mapping application. As with the process 700, various embodiments perform the process 1500 as an offline process that may be performed on a single computing device or distributed across several computing devices.
  • As shown, the process 1500 begins by receiving (at 1505) a road graph for a map region. The road graph, as described above and shown in FIG. 8, is a connected set of road segments and junctions. In some embodiments, the process 700 (or a similar road graph generation process) is run separately for different map regions (e.g., for states, rectangular geographic areas, land masses, etc.).
  • The geometry generation process 1500 generates (at 1510) an initial polygon representation of the road segments in the road graph. Some embodiments expand the piecewise linear centerline representation (which should be reasonably smooth after inserting vertices at a regular distance and then smoothing these vertices, in a process such as process 700 described above) into a polygon that follows the path of the road, having the width specified by its road segment data structure. The resulting polygon is, essentially, a structure with parallel sides that may appear to be curved. However, these polygons will need to be adjusted in many situations in order to generate a more realistic road animation.
  • The polygon adjustment, in some embodiments, includes smoothing the polygons to create more realistic rendered roads and junctions, eliminating overlaps, and annotating vertices with data that marks features to draw (e.g., shadows, bridge casings, curbs, tunnels, etc.). The next several operations in process 1500 describe these adjustment operations in a particular order. However, one of ordinary skill in the art will recognize that the once the initial polygons are grown, these operations may be performed in various different orders.
  • The process 1500 adjusts (at 1515) the geometries at junctions. In general, with the exception of overlaps between two or more geometries, the smoothing is primarily required at the junctions of the road graph. Within a road segment, the smoothing of the vertices described above should prevent any sort of obtrusions or irregularities. Some embodiments traverse the road graph and, at each junction, determine whether any modifications to the geometry are necessary to ensure a smooth, appealing rendered road at the client mapping application (and then make those modifications). These junctions may involve nothing more than a road continuing in a straight line where the speed limit changes (which will not involve any smoothing in some embodiments if the road width stays constant), but may also include freeway merges, roads intersecting at various angles, intersections between large and small roads (of which a freeway merge is one example), lane expansions, etc.
  • The following will describe various types of these junction smoothing examples, along with figures for some of the examples. When a road expands or contracts its number of lanes, some embodiments perform a particular smoothing operation. In some embodiments, the mapping service processing first determines whether a junction includes only two edges, and then that those two edges are connected within a road. If this is the case, and the number of lanes changes, then some embodiments perform one of the following transition smoothing operations to prevent unnatural-looking sharp angles.
  • FIG. 16 illustrates a first operation performed to smooth a lane expansion junction in which one of the sides of the roads stays straight (i.e., is “justified”), over three stages 1610-1630. As shown in the first stage 1610, in this example a first road segment 1605 connects into a second road segment 1615. The first road segment 1605 has data indicating that it has two lanes, while the second road segment 1615 has data indicating that it has three lanes. In some cases, this data is indicated in the road segment data received from the map data provider. When the map data provider includes lane information, in some cases the provider additionally includes lane connectivity data. In some cases, the lanes are numbered (e.g., from left to right), and the connectivity data indicates which lane in a first segment (e.g., segment 1605) continues into which lane in a second segment (e.g., segment 1615). As shown in the first stage 1610, in this case lane 1 of the first segment 1605 continues into lane 1 of the second segment 1615, while lane 2 of the first segment continues into both lanes 2 and 3 of the second segment. This indicates that the lane expansion occurs on the right side of the road (“right” based on the travel direction of the road). This lane connectivity data may be stored with the junction, or with one or both of the segments in various embodiments.
  • The second stage 1620 illustrates the initially-grown segment geometries 1625 and 1635 for the first and second road segments. As can be seen, the second segment geometry 1635 is wider than the first segment geometry 1625, and all of this additional width is at the right side of the road, with the left side of the road justified. When lane connectivity data is provided, some embodiments generate the geometry with the additional lane appearing in the correct location. However, when rendered using this geometry, the asphalt would appear to have a 90 degree angle, with the lane appearing out of nowhere. While occasionally freeway lanes do start in this manner, typically they expand smoothly out of the existing lane.
  • Thus, some embodiments automatically taper the lane expansion, as shown in the third stage 1630. Some embodiments identify a point along the edge of the narrower segment geometry (the geometry with fewer lanes) and taper from this point to the start of the edge of the wider segment. Some embodiments use a fixed distance to identify the point (e.g., 25 meters, 50 meters, etc.). The taper may be a straight line, as shown, or a curve. In addition, some embodiments employ the transition within the wider geometry, or spread the transition across the two geometries.
  • FIG. 17 illustrates the result 1700 of the smoothed lane expansion as rendered by a client mapping application of some embodiments (e.g., on the display of a portable device). For this figure, as well as a number of figures within this section, the result of specific road segments as rendered on a client mapping application are shown. In these figures, various controls and features that would typically be present in the mapping application display (e.g., a user location indicator (or navigation puck), a route line, additional land cover and building features, UI controls, etc.) are not displayed, so as to highlight the various aspects of the road segments. In FIG. 17, the asphalt makes a smooth transition from two to three lanes, and lane markings begin a bit before the lane is fully formed. As will be described below, some embodiments add road casing (e.g., curbs, guardrails, etc.) and lane markings. In different embodiments, the instructions for drawing the road casing may be communicated to the client mapping applications as additional geometries or as annotations to the geometry, with instructions for rendering based on the annotation stored at the client device.
  • FIG. 18 illustrates a second operation performed to smooth a lane expansion junction in which the road expands at both sides, over three stages 1810-1830. As shown in the first stage 1810, in this example a first road segment 1805 connects into a second road segment 1815. In this case, there is no lane connectivity data, but the first road segment 1805 has two lanes while the second road segment 1815 has three lanes. The lane count data may be provided directly from the map provider, or derived from either the provided road width or the road type.
  • The second stage 1820 illustrates the initially-grown segment geometries 1825 and 1835 for the first and second road segments. As can be seen, the second segment geometry 1835 is wider than the first segment geometry 1825, with the additional width split between the two sides of the road. When no lane connectivity data is available, some embodiments use a default lane expansion that splits the difference between the two sides of the road. However, when rendered using this geometry, the asphalt would appear to have a 90 degree angle on either side. While occasionally freeway lanes might start in this manner, typically they expand smoothly out of the existing lane.
  • Thus, some embodiments automatically taper the lane expansion on either side, as shown in the third stage 1830. Some embodiments identify, for each side of the road, a point along the edge of the narrower segment geometry and taper from this point to the start of the edge of the wider segment. Some embodiments use a fixed distance to identify the point (e.g., 25 meters, 50 meters, etc.). The taper may be a straight line, as shown, or a curve. In addition, some embodiments employ the transition within the wider geometry, or spread the transition across the two geometries.
  • FIG. 19 illustrates the result 1900 of the smoothed lane expansion as rendered by a client mapping application (e.g., on the display of a portable device). The asphalt makes a smooth transition from two to three lanes. Some embodiments bend two of the lanes in one direction and add the new lane on the other side in order to keep the lane markings continuous in some embodiments (e.g., choosing a random side for the new lane, or using a default.
  • The above examples are situations in which the junction in question only has two road segments. For junctions with three or more road segments, some embodiments identify special cases, and for other cases step through the list of road segments in the junction and perform corrections on geometries for subsequent pairs of roads. One such special case occurs when a bi-directional single carriageway road splits into a pair of corresponding dual carriageways. This often occurs when a median is introduced into a two-lane road (one lane in either direction). Some embodiments taper the road outwards (from the single carriageway to the dual carriageway) at the outer edges, and identify a merge point for the internal edges of the two dual carriageways. Some embodiments use lane information to determine the merge point (e.g., if one of the dual carriageways is one lane while the other is two lanes), while other embodiments use a default of a point at the center of the single carriageway, at its end.
  • When stepping through the list of road segments at a junction, some embodiments perform different corrections based on the angle between two segments. Some embodiments select a first road segment of the junction, then correct the corner formed by the left side of the segment geometry (as viewed exiting the junction) with the right side of the segment geometry (as viewed exiting the junction) for a second segment directly counterclockwise from the first segment. The second segment is then set as the first segment, and the process repeated for the next corner, until all of the corners have been corrected.
  • The following will describe various corrections performed for various junction angles, along with figures for some of the examples. These figures, though illustrating junctions with several road segments, show the geometries for only the two segment that are conformed to each other in the example.
  • FIG. 20 illustrates a tapering operation performed to smooth a corner between road segment geometries when the angle between the segments is greater than a first threshold angle (e.g., 170°), over three stages 2010-2030. In such a case, some embodiments automatically taper the side of one of the roads to meet the side of the other road. As shown in the first stage 2010, in this example a first road segment 2005 intersects with a second road segment 2015 at a junction, as well as with two additional road segments 2025 and 2035.
  • The second stage 2020 illustrates the initially-grown segment geometries 2040 and 2045 for the two road segments 2005 and 2015. The geometries for the other two road segments are not illustrated in this figure, as the mapping service processing of some embodiments corrects one corner of the junction at a time, and this example illustrates the correction between the segments 2005 and 2015. The mapping service processing of some embodiments would then perform a correction on the corner between segment 2015 and segment 2025, a correction on the corner between segment 2025 and segment 2035, and finally a correction on the corner between segment 2035 and segment 2005. As shown at this second stage 2020, the initial corner between geometry 2040 and geometry 2045 involves a visually jarring (and unrealistic) discontinuity, owing in part to the roads having different widths (although some embodiments perform the same process for roads of the same width).
  • Thus, some embodiments automatically taper the side of the narrower road segment to the side of the wider road segment, as shown by the modified geometry 2040 in the third stage 2030. In this case, because the wider segment is the more counterclockwise of the two road segments, the processing tapers the left side of the narrower segment to the right side of the wider segment (for this and subsequent examples, the “right” and “left” sides of a particular road segment are viewed from the perspective of a vehicle leaving the junction along the particular road segment). When the wider segment is the more clockwise of the two segments, the processing tapers the right side of the narrower segment to the left side of the wider segment. To perform the tapering operation, some embodiments fix a point along the side of the narrower segment geometry and taper from this point to the start of the side of the wider geometry. Some embodiments use a fixed distance to identify the point (e.g., 25 meters, 50 meters, etc.). The taper may be a straight line, as shown, or a curve. This operation is similar to the tapering illustrated in FIG. 16, and may also be performed when only two roads of different widths meet at a junction.
  • FIG. 21 illustrates the result 2100 of the smoothed junction as rendered by a client mapping application of some embodiments (e.g., on the display of a portable device). The asphalt indicates a smooth right turn from the first road segment (shown at the bottom of the display) to the second, wider segment (shown at the top right of the display). In addition, the display includes asphalt (and lane markings, road casing, etc.) for the other two segments that form the intersection. In different embodiments, the instructions for drawing the road casing may be communicated to the client mapping applications as additional geometries or as annotations to the geometry, with instructions for rendering based on the annotation stored at the client device.
  • FIG. 22 illustrates a projection operation performed to smooth a corner between road segment geometries when the angle between the segments is less than a first threshold angle and greater than a second threshold angle (e.g., between 120° and 170°), over three stages 2210-2230. In such a case, some embodiments automatically project the side of one of the roads to meet the side of the other road. As shown in the first stage 2210, in this example a first road segment 2205 intersects with a second road segment 2215 at a junction, as well as with two additional road segments 2225 and 2235.
  • The second stage 2220 illustrates the initially-grown segment geometries 2240 and 2245 for the two road segments 2205 and 2215. The geometries for the other two road segments are not illustrated in this figure, as the mapping service processing of some embodiments corrects one corner of the junction at a time, and this example illustrates the correction between the segments 2205 and 2215. The mapping service processing of some embodiments would then perform a correction on the corner between segment 2215 and segment 2225, a correction on the corner between segment 2225 and segment 2235, and finally a correction on the corner between segment 2235 and segment 2205. As shown at this second stage 2220, the initial corner between geometry 2240 and geometry 2245 involves a visually jarring (and unrealistic) discontinuity, owing in part to the roads having different widths (although some embodiments perform the same process for roads of the same width).
  • Whereas for the angle between the geometries shown in FIG. 20 the mapping service processing of some embodiments tapers the narrower road to the wider road, in this example the mapping service processing projects the side of the wider road onto the narrower road, as shown by the modified geometry 2240 in the third stage 2230. In this case, because the wider segment is the more counterclockwise of the two road segments, the processing projects the right side of the geometry 2245 onto the centerline (or the left side, in some embodiments) of the geometry 2240. When the wider segment is the more clockwise of the two road segments, the processing projects the left side of the wider segment onto the centerline (or right side, in some embodiments) of the narrower segment. Whereas the tapering operation involves changing the angle of the side of one of the segments, the projection simply extends the projected side in some embodiments, as shown in stage 2230.
  • FIG. 23 illustrates the result 2300 of the smoothed junction as rendered by a client mapping application of some embodiments (e.g., on the display of a portable device). The asphalt indicates a smooth right turn from the first road segment (shown at the bottom of the display) to the second, wider segment (shown at the top right of the display). In addition, the display includes asphalt (and lane markings, road casing, etc.) for the other two segments that form the intersection. In different embodiments, the instructions for drawing the road casing may be communicated to the client mapping applications as additional geometries or as annotations to the geometry, with instructions for rendering based on the annotation stored at the client device.
  • FIG. 24 illustrates a clipping operation performed to eliminate excess road for road segment geometries when the angle between the segments is less than a first threshold angle and greater than a second threshold angle (e.g., between 30° and 80°), over three stages 2410-2430.
  • In such a case, some embodiments automatically clip the side of one or both of the roads to avoid overshooting the other road. As shown in the first stage 2410, in this example a first road segment 2405 intersects with a second road segment 2415 at a junction, as well as with an additional road segment 2425.
  • The second stage 2420 illustrates the initially-grown segment geometries 2440 and 2445 for the two road segments 2405 and 2415. The geometry for the other road segment is not illustrated in this figure, as the mapping service processing of some embodiments corrects one corner of the junction at a time, and this example illustrates the correction between segments 2405 and 2415. FIG. 25, described below, illustrates the correction between segments 2415 and 2425. As shown at this second stage 2420, the initial corner between geometry 2440 and 2445 is not problematic, but the right side of the geometry 2445 overshoots the right side of geometry 2440, owing in part to geometry 2440 being narrower than geometry 2445.
  • Thus, the mapping service processing of some embodiments clips the left side of the more clockwise segment back to the centerline of the more counterclockwise of the two segments, and correspondingly clips the right side of the more counterclockwise segment back to the centerline of the more clockwise segment, as shown by the modified geometries 2440 and 2445 in the third stage 2430. In some embodiments, only the side of the wider road segment is clipped, but other embodiments clip both geometries as shown. As illustrated in the third stage 2430, this removes the excess “ear” of road that would otherwise be sticking out of the intersection unrealistically.
  • FIG. 25 illustrates an intersection operation performed to smooth a corner between the road segment geometry 2445 and a road segment geometry 2505 for the road segment 2425, over three stages 2510-2530. Some embodiments perform the intersection operation for angles greater than 180°, due to the gap left between the road segment geometries at such large angles. In such a case, some embodiments identify an intersection between the tangents of the road sides, and extend or clip the road geometries so that the sides end at this intersection point.
  • The second stage 2520 illustrates the segment geometry 2445 as modified in the operation shown in FIG. 24, as well as the initially-grown segment geometry 2505 for the road segment 2425. As shown, this (i) leaves a gap between the two geometries and (2) results in the wider segment 2445 overshooting the segment 2505. The second stage also illustrates a dashed line that represents the intersection of the projection of the left side of the more clockwise geometry 2445 with the projection of the right side of the more counterclockwise geometry 2505.
  • As shown in the third stage 2530, some embodiments either clip or project the sides of the geometries to this intersection point. In the case of the narrower segment 2505, the side is extended to fill in the gap, while in the case of the wider segment 2445, the side is clipped to prevent an overshoot of the geometry 2505.
  • FIG. 26 illustrates the result 2600 of the smoothed junction from the previous two figures as rendered by a client mapping application of some embodiments (e.g., on the display of a portable device). The asphalt indicates smooth turns between each of the subsequent roads, with no missing sections or excess bits of asphalt.
  • FIG. 27 illustrates a tapering operation performed to smooth a corner between road segment geometries in situations that fit characteristics of freeway on-ramps in some embodiments, over three stages 2710-2730. In this example, a first segment 2705 continues straight into a third segment 2725 at a junction, with a second segment 2715 entering the junction at a shallow angle relative to the first segment 2705. This situation fits the profile of a freeway merge in some embodiments: the first and third segments are a connected road, wider than the second segment, and the angle between the first and second segments is less than a threshold angle (e.g., 30°).
  • The second stage 2720 illustrates the initially-grown segment geometries 2735-2745 for the three road segments 2705-2725. The two freeway segment geometries 2735 and 2745 are significantly wider than the on-ramp segment geometry 2740. In addition, the third segment geometry 2745 is wider than the first segment geometry 2745, in order to accommodate the merge lane. However, as a result, the initial geometries leave a gap between the on-ramp geometry 2740 and the third segment geometry 2745.
  • Thus, the mapping service processing of some embodiments taper the outside (left side) of the second geometry 2740 to the right side of the third geometry 2745, as shown in the third stage 2730. In this case, the tapering is shown as a curved roadside, though different embodiments may use other methods (e.g., using a straight line to connect the segments). Some embodiments also use a taper from the left side of the first geometry 2735 to the right side of the third geometry 2745, as in the rendered result shown below.
  • FIG. 28 illustrates the result 2800 of the smoothed freeway merge junction as rendered by a client mapping application of some embodiments (e.g., on the display of a portable device). The asphalt indicates a smooth merge, rather than the choppy display that would be rendered as a result of the initial rectangular geometry. Furthermore, this figure illustrates that some embodiments render different roads differently. For example, some embodiments render freeways a different color (or shade) than other roads, including the freeway on-ramps.
  • In addition to modifying the geometries with tapering, projection, clipping, etc. operations, some embodiments use techniques to create more rounded corners at certain types of junctions. Rather than employing techniques to modify the already-generated road segment geometries in order to create rounded corners, some embodiments generate new geometries that create these round corners. In some embodiments, modifying the already-generated segment geometries would be extremely processing intensive.
  • FIG. 29 illustrates the generation of such additional geometries at a junction in order to create more realistic, rounded corners at the junction over three stages 2910-2930. The first stage 2910 illustrates a junction with four road segments 2905-2935, that intersect at right angles. The second stage 2920 illustrates the initial geometries for these road segments. In this case, all of the road segments have same width, so the geometries all have the same shape and size. Because the angles between the segments are all right angles, there is no need for any of the projection, clipping, or tapering described above.
  • The third stage 2930 illustrates the generation of additional geometries that overlap the road segment geometries and generate the rounded corners for the intersection. Specifically, the additional geometries 2940 (shown as solid lines, while the road segment geometries are represented by dashed lines at this stage) have edges that radiate out from the junction location towards points a fixed distance from the 90° corners formed by the segment geometries. The additional geometries 2940 also have curved lines between these points (or straight lines between enough vertices to approximate a curved line so that the intersection will be rendered with a more realistic, curved appearance.
  • FIG. 30 illustrates the result 3000 of the smoothed intersection as rendered by a client mapping application of some embodiments (e.g., on the display of a portable device). The asphalt does not make jarring 90° turns between the road segments, but instead has a more curved, pleasing appearance. In addition, the intersection includes stop lines and centerline markings, the generation of which is described below.
  • Returning to FIG. 15, the process 1500 also eliminates (at 1520) road overlaps. In some cases, two (or more) initially-grown road geometries will overlap incorrectly. Geometries for road segments that intersect at junctions should overlap, and when two road segments that do not form a junction but cross through the same latitude/longitude coordinates (e.g., a stacked-level road, roads going over/under each other, etc.), their geometries will overlap (as projected onto a flat plane representing the surface of the earth). However, when most other geometries overlap, this is most likely due to incorrect data and should be corrected. Without correction, the rendered map would indicate to a user of the mapping application that two roads intersect when in reality the roads do not.
  • The most common cases for such an overlap is when two corresponding dual carriageways overlap (e.g., Northbound and Southbound or Eastbound and Westbound freeways, opposite sides of arterial roads divided by a median, etc.). In most cases, the geometries for such corresponding dual carriageways should come very close to each other without actually overlapping. However, as the segment geometry is based on the centerline and width data for the segment, if any of this information is slightly inaccurate, then the geometries may not line up correctly. For example, when neither a lane count nor width is provided for a road, some embodiments derive the width based on the road type. However, if the road is actually narrower than usual for its road type, then the road geometry may end up larger than the actual road in the real world. Other situations that may cause such overlap include a freeway and its frontage road, roads that dead-end at a freeway rather than going over or under the freeway, etc.
  • Different embodiments use different techniques to remove these overlaps of road segment geometry. For instance, some embodiments push two roads apart at the location of the overlap, while other embodiments reduce the width of the road at the overlap. In addition, after moving the roads apart, when the roads are corresponding dual carriageways, some embodiments add geometry for a median between the road geometries.
  • FIG. 31 illustrates pushing two roads apart when they overlap, over three stages 3110-3130. The first stage 3110 illustrates a first road segment 3105 and a second road segment 3115, each as a sequence of vertices. As described above, some embodiments use a constant distance between centerline vertices for roads, in order to standardize operations performed using the vertices. When road segment data is received by the mapping service from a data provider, in some cases the vertex data representing the road segment centerlines may be defined at varying distances (e.g., with gaps of 10 meters, 25 meters, 50 meters, etc.). Some embodiments automatically define vertices at a predefined interval (e.g., every 10 meters) upon ingesting road segment data. This ensures that (i) the roads will have a more curved, realistic appearance than if the vertices were spread out, as the mapping service processing of some embodiments defines straight-line edges between the vertices. Furthermore, it makes the smoothing operations described above more successful by providing more points to move in the operation. Furthermore, defining the vertices at regular intervals enables more useful tests for road overlap.
  • The first stage 3110 additionally illustrates the road sides generated for the road geometries for the segments 3105 and 3115. As can be clearly seen, the two generated road geometries overlap for a section. In order to detect such overlaps, some embodiments generate capsules around each of the edges of a road centerline (the lines between subsequent vertices), and test the capsules for overlaps. The first stage 3110 illustrates four such capsules: capsules 3125 and 3135 for the first road segment 3105 and capsules 3140 and 3145 for the second road segment 3115. The capsules, in some embodiments, are defined to encompass the edge between two subsequent vertices, and extend out to the width of the road (using the centerline and width data for the road segment). While shown as ovals (i.e., ellipses) in this example, different embodiments use different shapes for the capsules, such as rectangles or other parallelograms, other ellipsoids, etc.
  • As shown at the first stage, the capsule 3125 for a first edge of the first road segment 3105 overlaps with the capsule 3140 for a first edge of the second road segment 3115. Additionally, the capsule 3135 for a second edge of the first road segment 3105 does not overlap with the capsule 3145 for a second edge of the second road segment 3115. In addition, though not shown in this figure, capsules for the two edges of each road segment in between those with capsules illustrated would most likely also overlap. For simplicity in illustrating the modification of the road segments, these additional overlaps are not illustrated or accounted for in FIG. 31.
  • In some embodiments, when an overlap is detected between capsules of two road segments, the mapping service processing applies a “force” to the vertices encompassed by the capsule, in order to push the road segments apart from each other. Some embodiments use a spring-mass equation to determine this force, with larger overlaps between capsules resulting in a larger force outward. That is, the larger the overlap, the more the mass “compresses” the conceptual spring, resulting in a larger outward force. Some embodiments apply this force to each of the four vertices within the two overlapping capsules, then taper the force off to nearby vertices as well. The second stage 3120 illustrates the application of these forces, with the largest force arrows applied to the two vertices inside each of capsules 3125 and 3140, and smaller force arrows applied to the vertices on either side.
  • In some embodiments, the mapping service processing identifies each set of overlapping capsules, and identifies a force to apply to each vertex as a result of that individual overlap. After identifying the forces on the different vertices, the mapping service processing integrates the forces on each vertex to arrive at a new centerline path for the road segments. The processing then performs the same capsule test to determine whether any overlap between the road segment remains. If there is still overlap, the mapping service processing applies additional force to the vertices and pushes them apart again. The third stage 3130 illustrates that the two road segments 3105 and 3115 have been pushed apart, so that capsules around the edges of the first segment do not overlap at all with capsules around the edges of the second segment. As shown, the road sides for the two road segment geometries are now independent and do not overlap at all.
  • Other embodiments use different mechanisms to move the vertices apart. For instance, even with multiple overlapping capsules, some embodiments move the vertices as soon as the first overlap is detected, then move on to the next set of vertices once the first identified sets have been pushed far enough apart to avoid any overlap. In addition, while the example illustrates that forces are applied to vertices around those that overlap, some embodiments only move the vertices of the edge that actually causes the overlap (i.e., only the vertices within capsule 3125 and 3140). Furthermore, different embodiments may use different equations (i.e., varying from the spring-mass equation) to determine how much to push vertices away from each other, as well as different equations for calculating how far to move the surrounding vertices.
  • Moving the centerline vertices of the road segments is one option employed by some embodiments to handle overlapping road geometries. Some embodiments, on the other hand, reduce the width of the road in the vicinity of the overlap rather than moving the centerline (i.e., reduce the size of the road geometry).
  • FIG. 32 illustrates reducing the widths of two road segments when the road segments overlap, over three stages 3210-3230. The first stage 3210 illustrates a first road segment 3205 and a second road segment 3215, each as a sequence of vertices (similar to the road segments shown in FIG. 31). As described above, some embodiments use a constant distance between centerline vertices for roads, in order to standardize operations performed using the vertices. When road segment data is received by the mapping service from a data provider, in some cases the vertex data representing the road segment centerlines may be defined at varying distances (e.g., with gaps of 10 meters, 25 meters, 50 meters, etc.). Some embodiments automatically define vertices at a predefined interval (e.g., every 10 meters) upon ingesting road segment data.
  • The first stage 3210 additionally illustrates the road sides generated for the road geometries for the segments 3205 and 3215. As can be clearly seen, the two generated road geometries overlap for a section. In order to detect such overlaps, some embodiments generate capsules around each of the edges of a road centerline (the lines between subsequent vertices), and test the capsules for overlaps. The first stage 3210 illustrates two such capsules: capsules 3225 for the first road segment 3205 and capsule 3235 for the second road segment 3215. The capsules, in some embodiments, are defined to encompass the edge between two subsequent vertices, and extend out to the width of the road (using the centerline and width data for the road segment). While shown as ovals (i.e., ellipses) in this example, different embodiments use different shapes for the capsules, such as rectangles or other parallelograms, other ellipsoids, etc. Some embodiments may employ both the solution shown in FIG. 31 and that shown in FIG. 32, and use the same capsules for each solution.
  • As shown at the first stage, the capsule 3225 for an edge of the first road segment 3205 overlaps with the capsule 3235 for an edge of the second road segment 3215. In addition, though not shown in this figure, capsules for the two edges of each road segment below those with the overlapping capsules illustrated would most likely also overlap. For simplicity in illustrating the modification of the road segments, these additional overlaps are not illustrated or accounted for in FIG. 32.
  • In some embodiments, when an overlap is detected between capsules of two road segments, the mapping service processing reduces the width of the road segments at the location of the overlapping capsules. As shown in the second stage 3220, some embodiments move the road sides at the location of the overlap inward towards the centerline by a particular distance. Some embodiments move this portion of the road side for a particular segment a distance proportional to the amount of overlap. The distance may be just enough to reduce the overlap at the location, or this amount plus additional leeway so that there is a gap between the two road segment geometries. In addition, some embodiments only move the road side that causes the overlap inward, while other embodiments symmetrically modify the other side of each road as well (so that the centerline remains in the center of the road).
  • To prevent the rendered roads on a client mapping application from appearing to have a sudden chunk removed from the road, some embodiments select a point along the roadside in either direction (e.g., 100 meters, 500 meters, etc. from the affected vertices) and hold these points fixed. The mapping service processing then tapers the width reduction out from the overlapping section to the fixed points.
  • The third stage 3230 illustrates the road geometries for the segments 3205 and 3215 after the widths of the roads have been reduced. As shown, the road geometries no longer overlap at all (at least in the sections shown in the figure). Some embodiments, after detecting an overlap between any two capsules, perform the process to reduce the width at that location and taper out the width reduction. The processing then retests that pair of edges and continues on to identify whether any overlapping road sections remain. On the other hand, other embodiments first identify all of the overlapping sections, reduce the widths at each such section, and calculate the different tapers required for each of the width reductions.
  • In addition to the geometry corrections performed at 1515 and 1520 to smooth junctions and eliminate road overlaps, the process 1500 also generates (at 1525) road markings to display on the roads. These road markings, in some embodiments, may include lane markings, medians, stop lines and/or crosswalks at intersections, etc.
  • For example, some embodiments automatically add medians between dual carriageways. As described in the previous subsection, some embodiments identify road segments (or aggregate roads) as being corresponding sides of a road (e.g., opposing directions of a freeway or sides of an arterial road separated by a median, etc.) using the road segment data. In some embodiments, this road segment data indicates that a road is a dual carriageway (sometimes referred to as a divided highway, as opposed to a single carriageway that carries traffic in both directions), and other properties (both geometric and attribute data for the road segments) indicate a likelihood that two roads are corresponding dual carriageways.
  • Such dual carriageways often have the two sides separated by various different kinds of medians. For instance, different areas may use concrete raised medians, grass medians, drawn medians (e.g., different combinations of yellow lines), dividers, etc. Some embodiments generate geometries that fill in the gaps between corresponding dual carriageway roads, and then assign these geometries properties so that they are rendered as medians. Some embodiments use the locations of the vertices of the road sides to determine locations for the median vertices, so that the median lines up exactly with the side of the road.
  • Different embodiments render the medians differently. For example, some embodiments use a single median type for all dual carriageways, while other embodiments have different types. Much like roads, land cover, etc., stylesheets stored at the client can define different median styles that are drawn differently. The median geometries from the mapping service are tagged with different styles (e.g., arterial road median, freeway median, etc.) that correspond to differently rendered graphics by the client mapping application.
  • FIGS. 33 and 34 illustrate dual carriageways with two different types of medians. FIG. 33 illustrates two rendered roads 3305 and 3315, that are corresponding dual carriageways. In addition, the application displays a design of yellow lines representing a median 3310 in between the two roads (specifically, a pair of double yellow lines, with diagonal lines connecting them. FIG. 34 illustrates a concrete median 3405 drawn between the two dual carriageways 3305 and 3315.
  • In addition to medians, some embodiments generate geometries for various types of road paint (e.g., lane dividers, stop lines, etc.). In some embodiments, this includes the lane markings shown in the rendered results described above. To generate the lane markings for a road segment, some embodiments use the lane count information stored in the road segment data structure (which may be derived from either the width data or the road type data). In addition, special lanes such as carpool lanes may be indicated in the road segment data and can have geometry generated.
  • In addition, some embodiments recognize junctions at which a driver would likely have to stop at a stop sign or light. The mapping service of some embodiments receives this data from map providers (e.g., as information stored in the junction data). Thus, a particular junction might indicate a 4-way stop, a 2-way stop (picking out particular road segments as having the stop signs), a traffic light, etc. In some embodiments, the mapping service processing derives this information based on the road types at the junction. For instance, when a connector road intersects a major arterial road, some embodiments assume that the connector road has a stop sign with the major arterial road having the clear right of way. When two major arterial roads intersect, the mapping service processing assumes that the intersection will be controlled by a stoplight, and adds stop line markings to all of the road segments at the junction.
  • FIG. 35 illustrates an example of geometries for such a junction 3500. When all of the road segment geometries at the intersection have the same width, and line up at 90° angles, then generating the stop lines is easy (as shown below). However, the four road segments 3505-3520 are not so well aligned. Instead, the segments have different widths, and the segment 3510 intersects the junction at a different (non-right) angle. In such a situation, for each particular road segment, the mapping service processing identifies the line perpendicular to the particular road segment's centerline that is closest to the intersection and touches both sides of the particular road segment's geometry without also intersecting the other road segment geometries. While shown for a more complex junction, some embodiments also use this process to identify the stop line locations in the simpler cases as well.
  • The dashed lines 3525 in FIG. 35 illustrate these lines for the junction 3500. The mapping service processing then generates geometries for the stop lines that end at these identified lines (the dashed lines 3525). For single carriageway road segments (that have two-way travel), the processing only generates the stop line to extend halfway across the road segment. In addition, some embodiments push the stop lines back from the edge of the intersection (the edge being represented by the dashed line in this figure) by a particular distance (e.g., two feet, five feet, etc.).
  • FIG. 36 illustrates the result 3600 of junction 3500 as rendered by a client mapping application of some embodiments (e.g., on the display of a portable device). As shown, a thick white line is drawn halfway across each of the road segments at the location identified by the dashed lines of FIG. 35. The interior (to the intersection) edge of the stop line geometry is drawn at the indicated line, with the stop line extending a ways into the road segment (away from the intersection). Some embodiments push the stop line a fixed distance away from the intersection as well. In addition, lane markings are generated such that they stop at the stop line, or shortly before.
  • Again returning to FIG. 15, the road geometry creation process 1500 next specifies (at 1530) annotation information on the road geometry, then ends. In some embodiments, this annotation information is stored on the polygon vertices (or edges, as the two are essentially interchangeable) that directs the mesh building modules and/or rendering engine of the client mapping application to apply particular characteristics to the rendered output. For example, some embodiments specify different types of road casing (i.e., the objects located at the sides of the road) through the road geometry vertices, instructing the client application to draw curbs, sidewalks, bridge casings (and corresponding shadows), tunnels, stacked roads, etc. In some embodiments, the instructions for drawing these casings are stored on the client device as part of the mapping application. The client mapping application then reads the information stored on a particular vertex and generates the appropriate road casing for the edge that corresponds to the vertex.
  • The following illustrates several examples of different annotations of some embodiments for road vertices to indicate types of casings to be drawn. FIG. 37 illustrates an example of the use of vertex annotation to specify bridge casing for an overpass, where one road travels over another road and the roads do not form a junction. As shown in FIG. 37, the two road geometries 3705 and 3710 intersect in flat space. However, the road segment data specifies that the road segment for which the geometry 3705 is generated has a higher elevation than the road segment for which the geometry 3710 is created (either using absolute elevation data or relative elevation data). In addition, while shown as one segment for each of the two roads, in some embodiments the roads would be defined using several segments (e.g., for the road 3705, a first segment from an elevation of 0 to an elevation of 1, a second segment with an elevation of 1, and a third segment from an elevation of 1 to an elevation of 0.
  • FIG. 37 also illustrates several vertices 3715-3735 used to define the sides of the road geometries 3705 and 3710. Each particular vertex defines a directed edge from the particular vertex to a next vertex in a sequence. Thus, for example, annotation for the vertex 3735 defines how the client mapping application will draw the edge from the vertex 3735 to the vertex 3730, annotation for the vertex 3730 defines how the client mapping application will draw the edge from the vertex 3730 to the vertex 3725, etc. Different vertices along a single road segment may have different annotations, so that portions of a single road segment will be drawn with different features (e.g., different road casings).
  • In this case, the vertex 3715 (as well as the other vertices for road segment geometry 3710) specifies that it is a vertex of a connector road, and to use the default casing. In some embodiments, different types of roads (e.g., connector, arterial, freeway, etc.) may not only be drawn differently (e.g., different color/texture for the asphalt, different widths, etc.) but also may have different casings (e.g., a curb for a connector road). While this shows an actual specification of a default casing, some embodiments have no specific annotation on vertices for the default casing (or any other property for which the vertex provides annotation).
  • Three of the illustrated vertices 3725-3735 specifically indicate bridge casing for their edges of the geometry 3705, while the vertex 3720 indicates a default arterial road casing. Just as different types of roads may have different default casings, different types of roads may also have different bridge casings. That is, the client mapping applications may contain instructions to draw different overpasses for arterial roads, freeways, etc. The vertex 3720, while located at the edge of the overpass area, does not specify bridge casing, but rather, specifies a default road casing for its edge. This is because its edge is directed away from the overpass, towards the next vertex to the left (not shown) for that side of the road geometry 3705.
  • FIG. 38 illustrates the result 3800 of the road segments 3705 and 3710 as rendered by a client mapping application of some embodiments (e.g., on the display of a portable device). In this case, the asphalt for the connector road is rendered using the same color/texture as the asphalt for the arterial road, although some embodiments may render the roads differently. In addition, lighter-colored curbs are drawn along the edges of the two roads for locations for which the vertices specify a default road casing. For the overpass section, however, the client application draws an overpass bridge according to some embodiments. Furthermore, the application renders a shadow onto the asphalt of the connector road to more realistically illustrate the overpass. If a user were to rotate the view of the map for these roads, then a similar bridge casing would be rendered for the other side of the overpass. In addition, while the shadows appear only for the overpass of the connector road, some embodiments also render shadows underneath the arterial road as it moves upwards from the ground to the overpass.
  • FIG. 39 illustrates an example of the use of vertex annotation to specify an edge of a road segment geometry as an interior edge, indicating that no casing should be drawn for the directed edge from the annotated vertex. Some embodiments use such an annotation where roads meet at junctions, in order to prevent the client mapping application from drawing a curb in the middle of the road. As shown in FIG. 39, two road segment geometries 3905 and 3910 meet at a junction. In this case, the road segments are connected as subsequent portions of an aggregate road; however, the same road casing annotation may also be used at junctions representing intersections of more than one road in some embodiments.
  • FIG. 39 also illustrates several vertices 3915-3925 used to define the sides of the road geometry 3905. The other road geometry 3910 is also defined by vertices, including vertices located at the same point as the vertices 3915 and 3920. As in the previous figure, each particular vertex defines a directed edge from the particular vertex to a next vertex in a sequence. Thus, for example, annotation for the vertex 3915 defines how the client mapping application will draw the edge from the vertex 3915 to the vertex 3920, annotation for the vertex 3920 defines how the client mapping application will draw the edge from the vertex 3920 to the vertex 3925, etc.
  • In this case, all of the vertices 3915-3925 (as well as the other vertices for road segment geometry 3910) specify that they are vertices of a connector road. In addition, the vertices 3925 and 3920 specify to use default casing. While this shows an actual specification of a default casing, some embodiments have no specific annotation on vertices for the default casing (or any other property for which the vertex provides annotation). In addition, the vertex 3915 specifically indicates to use interior casing (i.e., that the directed edge associated with the vertex 3915 is an interior edge of the road. In some embodiments, the interior casing annotation directs the client mapping application to not draw any road casing at all for those edges.
  • The vertex 3920, while located at the corner of the road geometry next to the interior edge, specifies the default casing rather than interior casing. This is because its edge is directed towards the vertex 3925. Furthermore, in some embodiments vertices for the road geometry 3910 would be located at the same points as the vertices 3915 and 3920, with the vertex co-located with vertex 3920 specifying the interior casing (assuming the direction of the edges was the same for the geometry 3910 as for 3905.
  • FIG. 40 illustrates the result 4000 of the road segments 3905 and 3910 as rendered by a client mapping application of some embodiments (e.g., on the display of a portable device). In this case, the asphalt for the first road segment blends smoothly into the asphalt for the next road segment, with no visual indication of a transition from one road segment to the next. The application also draws curbs along either side of the road as the default casing. In addition to polygons for the lighter colored curbs, some embodiments also draw details such as the small shadows generated by the curbs, in order to provide a more 3-dimensional feel to the display, at least in some modes of the client mapping application. While the interior (i.e., facing other road segments) edges of roads are specified as such so that curbs and other road casing are not drawn in the middle of a road, some embodiments also use the interior annotation for roads that do not have casing on their exterior edges, such as country roads that lie at the same level as the grass next to the road, with no curb or other casing.
  • FIG. 41 illustrates an example of the use of vertex annotation to specify a tunnel for a road segment, indicating that the tunnel should be drawn over the road segment. Some embodiments use such an annotation to indicate the entrance/exit for a tunnel, as well as middle of the tunnel, so that the client mapping application will draw the tunnel when rendering the road segment. As shown in FIG. 41, two road segment geometries 4105 and 4110 meet at a junction. In this case, the road segments are connected as subsequent portions of an aggregate road; however, the same road casing annotation may also be used at junctions representing intersections of more than one road in some embodiments.
  • FIG. 41 also illustrates several vertices 4115-4130 used to define the sides of the road geometry 4110. The other road geometry 4105 is also defined by vertices, including vertices located at the same point as the vertices 4115 and 4130. These vertices, in some embodiments would be annotated to specify default casing or interior casing, for the different vertices. As in the previous figures, each particular vertex defines a directed edge from the particular vertex to a next vertex in a sequence. Thus, for example, the annotation for the vertex 4115 defines how the client mapping application will draw the edge from the vertex 4115 to the vertex 4120, annotation for the vertex 4125 defines how the client mapping application will draw the edge from the vertex 4125 to the vertex 4130, etc.
  • In this case, all of the vertices 4115-4130 (as well as the vertices for the road segment geometry 4105) specify that they are part of an arterial road. In addition, the vertex 4130 specifies to use tunnel entrance casing, while the vertices 4115-4125 specify to use tunnel casing. The tunnel entrance casing annotation, in some embodiments, specifies that the particular edge (the edge of segment geometry 4110 that crosses the roadway is the entrance to a tunnel and should be drawn as such. The tunnel casing annotation of some embodiments specifies that the edges are the sides of a tunnel, and thus a tunnel should be drawn across the road. at the location of those edges.
  • FIG. 42 illustrates the result 4200 of the road segments 4105 and 4110 as rendered by a client mapping application of some embodiments (e.g., on the display of a portable device). In this case, the first road segment is displayed with asphalt and curb, the default rendering of some embodiments. For the second road segment, however, the application draws the curved tunnel entrance, and then a rounded covering of the road segment. At the other end of the road segment, the application would render a tunnel exit. In addition, the application renders a shadow below the entrance, resulting in the asphalt being darkened at this location.
  • FIG. 43 illustrates an example of the use of vertex annotation to specify a sidewalk for a side of a road segment. This figure illustrates a single road geometry 4305 for a road segment that travels in a straight line. As shown, several vertices 4310-4325 are used to define the sides of the road geometry 4305. Each particular vertex defines a directed edge from the particular vertex to a next vertex in a sequence. Thus, for example, annotation for the vertex 4310 defines how the client mapping application will draw the edge from the vertex 4310 to the vertex 4315, annotation for the vertex 4320 defines how the client mapping application will draw the edge from the vertex 4320 to the vertex 4325, etc. Different vertices along a single road segment may have different annotations, so that portions of a single road segment will be drawn with different features (e.g., different road casings).
  • In this case, the vertices 4310 and 4315 specify that they are vertices of a connector road, and to use the default casing. As explained above, different types of roads may have different default casings (e.g., curb for a connector road or arterial road, guardrail for certain other types of roads, etc.). While this shows an actual specification of a default casing, some embodiments have no specific annotation on vertices for the default casing (or any other property for which the vertex provides annotation).
  • The vertices 4320 and 4325 specifically indicate sidewalk road casing for their edges of the geometry 4305. Just as different types of roads may have different default casings, different types of roads may also have different sidewalks. That is, the client mapping applications may contain instructions to draw different sidewalks for connector roads, arterial roads, etc. (e.g., wider sidewalks for arterial roads).
  • FIG. 44 illustrates the result 4400 of the road segment 4305 as rendered by a client mapping application of some embodiments (e.g., on the display of a portable device). In this case, the asphalt for the arterial road is rendered in the same manner as shown above, and the left side (with the default road casing) simply has a curb drawn. For the right side of the road, however, the application renders a sidewalk in addition to the curb. In addition to polygons for the lighter colored curbs, some embodiments also draw details such as the small shadows generated by the curbs, in order to provide a more 3-dimensional feel to the display, at least in some modes of the client mapping application.
  • The above examples illustrated different types of annotations that can be applied to the road segment geometries. In some embodiments, multiple types of road casings may be applied to a single edge by annotating the edge's vertex with several types of annotation. In the above example of FIG. 43, the sidewalk annotation implied that the client application should render both a curb and a sidewalk.
  • FIG. 45 illustrates an example of the use of several annotations for a single vertex of some embodiments. Specifically, FIG. 45 illustrates an example of using vertex annotation to specify an overpass that includes a sidewalk on one side of the bridge. The geometries 4505 and 4510 are similar to the geometries 3705 and 3710 of FIG. 37, with the latter, a connector road, passing underneath the former, an arterial road. In fact, the difference from FIG. 37 is that the vertices 4515-4525 include annotations that specify both a bridge casing and a sidewalk casing.
  • FIG. 46 illustrates the result 4600 of the road segments 4505 and 4510 as rendered by a client mapping application of some embodiments (e.g., on the display of a portable device). Like FIG. 45, the asphalt for the connector road is rendered using the same color/texture as the asphalt for the arterial road and the application draws the lighter-colored curbs along the edges of the two roads. For the overpass section, the client application renders not only the overpass and its shadow, but a sidewalk atop the overpass on the side of the road annotated with the sidewalk. In this case, the other side of the road segment 3705 is not annotated to specify a sidewalk, so the application does not render one.
  • In the previous examples, the mapping service processing simply specified a casing type for the vertices. In some embodiments, the mapping service can also specify various different variables for different types of casings, that modifies how the casings are rendered. For instance, the height for bridge casings may be specified in the annotation data (i.e., based on the road segment elevation information). In addition, the sidewalk width, curb height, guardrail height, tunnel thickness, curb color, etc. may be varied in different embodiments.
  • FIG. 47 illustrates an example of using the vertex annotation data to vary a property of the road casing for a road geometry 4705. Specifically, the road geometry 4705 includes two vertices 4710 and 4715 on one side and two vertices 4720 and 4725 on the other side. The two vertices 4710 and 4715 specify for the client application to render a sidewalk casing, and include a width of 1 meter for that sidewalk. On the other side of the road, the two vertices 4720 and 4725 also specify for the client application to render a sidewalk casing, this time with a width of 1.5 meters.
  • FIG. 48 illustrates the result 4800 of the road segment 4705 as rendered by a client mapping application of some embodiments (e.g., on the display of a portable device). The rendering is similar to that shown in FIG. 44. However, the rendered road now has sidewalks on both sides, and the sidewalks are of a different width (as specified in the annotation data).
  • The above examples illustrate the use of vertex annotation data to specify road casing data for some embodiments. However, as other map objects (e.g., buildings, land cover polygons, etc.) are described in map tiles using vertices in some embodiments, these other objects may also contain vertex annotations in their descriptions. For instance, building details can be specified using such annotation (e.g., different color faces, different types of moulding, etc.), as can aspects of the land cover (e.g., how to draw different borders of the land cover polygons).
  • After specifying the annotation information, the road geometry creation process ends. As mentioned above, in some embodiments the specific order of the operations to create the road geometry may be different. Furthermore, some embodiments may use parallel processing to perform some or all of the road geometry operations to several road segments (or sets of road segments) at once.
  • C. Server Side Generation of Intersection Data
  • Having described the server operations that lead directly to the road geometries (e.g., defining aggregate roads and the creation of road geometry), the generation of intersection data using the junction data referred to above will now be discussed. When requesting a route, the client mapping application in some embodiments receives data about each of the intersections that the route traverses, that indicates the different branches of the intersection and notes through which branches the route enters and exits the intersection. In some embodiments, this intersection information is stored by a mapping service that the mapping application accesses in order to retrieve map data as well as route and navigation information.
  • As mentioned above, the mapping service of some embodiments receives data specifying each junction of road segments. In some embodiments, the mapping service automatically generates additional data for each of these junctions stored in the map data, and in some embodiments converts the junction data into intersection data. This junction information simplifies each received junction (or a set of related junctions that are viewed in the real world as a single intersection) into a set of branches leaving the junction at different angles. When a user requests a route through a mapping application operating on a device, the device sends the request to the mapping service, which generates a route from a starting location to an ending location. The mapping service also generates turn-by-turn navigation instructions for the route in some embodiments, using the intersection data. The mapping service identifies the intersections at which maneuvers are made, and modifies the intersection data to be specific to the maneuver made during the route. This data is then sent to the user device on which the client mapping application runs. The following subsections first introduce the creation of navigation data for a route, then discuss the precalculation of intersection data by the mapping service (so that the data is available for use in generating navigation data), and then finally describe specific types of modifications made to the intersection data for a requested route.
  • 1. Navigation Data Creation
  • FIG. 49 conceptually illustrates an operation performed by a mapping service of some embodiments to generate a route for a requesting device and provide the route, with navigation instructions, to the requesting device. FIG. 49 illustrates this operation over six stages 4910-4960, in which the mapping service receives a request for the route, generates the route, generates intersection data for the route, and provides the route to the device, which uses the information to display navigation instructions.
  • As shown, each stage of FIG. 49 illustrates a device 4905 and a mapping service 4900. The device 4905 may be a handheld device in some embodiments (e.g., a smart phone, tablet device, etc.), or may be a dedicated navigation device (e.g., a navigation system built into an automobile, a portable navigation device, etc.). In addition, in some embodiments, the device 4905 may be a non-portable device such as a desktop computer or other non-portable computing device.
  • The mapping service 4900 is a service to which the device 4905 connects (e.g., via a wired connection, wireless connection such as a cell network, Wi-Fi, etc.) in order to request and receive map data, route data, turn-by-turn navigation data, as well as additional information (e.g., information about places located on the map, etc.). As shown, the mapping service 4900 stores map data 4915 and intersection data 4925, and includes a map generator 4935 and route generator 4945, among other modules (not shown).
  • The map data 4915 provides data from which viewable map regions and routes can be generated. This map data, in some embodiments, includes latitude and longitude data, name data, as well as descriptive data about roads and other pathways (e.g., walkways, ferry routes, bike paths, etc.), natural features (e.g., rivers, lakes, mountain ranges, etc.), places of interest (e.g., buildings, businesses, parks, etc.), and other map items. In some embodiments, for example, a pathway is defined as a series of latitude/longitude vertices, a name, and descriptive data. This descriptive data may include a form of way (i.e., whether the pathway is a single carriageway or a part of a dual carriageway, whether the pathway is a one-way path), the class of road to which the path belongs (e.g., motorway, local road, private road, bicycle path, etc.), as well as other information). In some embodiments, this map data is compiled by an outside source (i.e., a map provider) and provided to the mapping service, while in other embodiments the mapping service provides its own map data. The map data may also be a hybrid of outsider-provided and internally-generated data. In addition, the map data may include geometry data for various map constructs, such as roads, land cover, etc.
  • The intersection data 4925 provides pretabulated data for the intersections of road paths in the map data. In some embodiments, as described below, the mapping service automatedly calculates intersection data for road pathway intersections using the map data. This intersection data 4925 may be stored by denoting an intersection type (e.g., point, roundabout) and a series of branches coming in and out of the intersection at different angles. While the map data 4915 and the intersection data 4925 are shown as separate storages, these may both be stored on the same physical storage or on separate physical storages, and the intersection data 4925 may in fact be part of the map data 4915. In addition, one or both of the map and intersection data might be distributed across several physical storages (e.g., a series of disks for storing the map data).
  • The map generator 4935 of some embodiments generates map information (e.g., map tiles) to transmit to the requestor device. The requestor device requests a map for a particular region (e.g., using latitude/longitude information), and the map generator 4935 creates (or uses pre-generated) map tiles for the region, then sends data for these tiles (e.g., as encoded vector and/or image data) to the device.
  • The route generator 4945 calculates optimal routes between two or more points in response to user requests. In some embodiments, the route generator 4945 calculates the routes based on the map data, using optimization algorithms. The routes may be defined as a series of intersections, a series of road pathways, or in other manners. In addition, when a user requests a route, the route generator 4945 provides intersection data for use by the device in turn-by-turn navigation. In some embodiments, the intersection analyzer 4955 retrieves intersection data 4925, and modifies this data for navigation of the route, as described below.
  • As shown, at stage 4910, the device 4905 sends a request for a route to the mapping service 4900. In some embodiments, the user enters a starting address (or place) and an ending address (or place), potentially including additional midpoint locations (e.g., starting at A, going to B, then going to C from B). The device then transmits location information to the mapping service. In some embodiments, the device translates the locations into latitude and longitude data, while in other embodiments this conversion is performed by the mapping service.
  • At stage 4920, the route generator 4945 accesses the map data 4915 in order to generate one or more routes for the series of locations. In some embodiments, the route generator 4945 uses an optimization algorithm to find the best (and second best, third best, etc.) route that connects the series of locations.
  • At stage 4930, the intersection analyzer 4955 identifies maneuvers along the route for which navigation directions need to be generated and retrieves intersection information for these maneuvers. Some embodiments generate turn-by-turn navigation directions to provide to the device along with the route. To generate these directions, the mapping service 4900 identifies each time the route changes pathways, at which point the user following the directions will have to perform a maneuver (e.g., right turn, slight left turn, U-turn, merge, etc.). In some embodiments, each of these pathway changes corresponds to a pretabulated intersection stored in the intersection data 4925. The intersection analyzer 4955 retrieves this intersection data. In some embodiments, each intersection is stored as a series of branches coming out of the intersection at various angles (e.g., based off of North=0°). In some embodiments, in addition to the intersection data, the route generator creates routing directions, that generally describe the maneuver to be performed. Examples of such descriptions include “turn left”, “highway off ramp”, “U-turn”, etc. In other embodiments, this description is derived by the client mapping application based on the received intersection data.
  • Next, at stage 4940, the intersection analyzer 4955 generates intersection information designed for the route. In some embodiments, this entails modifying the angles to set the direction of travel into the junction to 0° (i.e., setting the branch on which the route enters the junction to 180°). This effectively rotates the intersection description by the difference between due North and the route's incoming direction of travel. In addition, the intersection analyzer 4955 tags one of the branches as the exit branch. Some embodiments tag an entrance branch as well, while other embodiments rely on the device to identify the 180° branch as the entrance branch.
  • Stage 4950 illustrates that the mapping service 4900 then transmits (e.g., via the same network that the device used to transmit the route request) the route data (i.e., route data and intersection data for navigation) to the device 4905. As shown at stage 4960, the device 4905 then uses the intersection and route data generated by the mapping service to display navigation instructions for the user of the device. In some embodiments, the navigation instructions include a display of the intersection along with a stylized arrow showing the maneuver (in this case, a right turn) through the intersection.
  • While the mapping service 4900 is displayed as including a map generator module and a route generator module, one of ordinary skill in the art will recognize that the mapping service may include additional modules, or different breakdowns of modules. The mapping service may consist of a single computing device (e.g., a server) storing all of the functionality and data, or the functionality may be distributed between multiple servers (e.g., one process on a first server and a second process on a second server, numerous servers that perform the same operation in parallel for different users, or other configurations of computing devices that perform the functionality described herein).
  • FIG. 50 conceptually illustrates a process 5000 performed by the mapping service of some embodiments in order to generate and transmit route and intersection data to a user. As shown, the process 5000 begins by receiving (at 5005) a request for a route between two locations on a map. In some embodiments, when the user requests a series of more than two locations, each segment is treated as a separate route (i.e., from point A to point B is a first route, then point B to point C is a second route).
  • The process then generates (at 5010) at least one route between the locations using map data. In some embodiments, the process uses an optimization algorithm to identify the best (or two best, three best, etc.) routes between the two locations. These routes may be described as a series of vertices along pathways, a series of intersections between pathways, or with another description.
  • With the routes generated for the start and end locations, process 5000 selects (at 5015) one of the generated routes in order to create turn-by-turn instructions for the route. The process then identifies (at 5020) maneuvers to make along the route. In some embodiments, the mapping service identifies each time the route changes pathways, at which point the user following the directions will have to perform a maneuver (e.g., right turn, slight left turn, U-turn, merge, etc.).
  • Next, the process retrieves (at 5025) intersections for each of the maneuvers. In some embodiments, each of these pathway changes corresponds to a pretabulated intersection stored by the mapping service. The generation of these intersections is described in detail below. In some embodiments, each intersection is stored as a series of branches coming out of the intersection at various angles (e.g., based off of North=0°). In addition, the intersection data stores the type of intersection in some embodiments (e.g., point, roundabout, traffic square, etc.).
  • The process then modifies (at 5030) the intersection information for each of the maneuvers. In some embodiments, this entails modifying the angles to set the direction of travel into the junction to 0° (i.e., setting the branch on which the route enters the junction to 180°). This effectively rotates the intersection description by the difference between due North and the route's incoming direction of travel. In addition, some embodiments tag one of the branches as the exit branch. Some embodiments tag an entrance branch as well, while other embodiments rely on the device to identify the 180° branch as the entrance branch.
  • The process 5000 next determines (at 5035) whether additional routes remain for which to generate maneuver/intersection information. When additional routes remain, the process returns to 5015 to select the next route. Different variations of routes from a start location to an end location may overlap in part, in which case some embodiments reuse the already-generated set of intersections for the overlapping portions.
  • Once intersections are generated for all of the routes, the process transmits (at 5040) the route and intersection information to the requestor (e.g., a requesting device). As mentioned, the requesting device uses this information in some embodiments in order to generate turn-by-turn navigation, including stylized junction/maneuver arrows.
  • 2. Precalculation of Intersection Data
  • As mentioned above, some embodiments precalculate intersection data from the stored map data (e.g., road segment and junction data). The mapping service then stores this intersection data for use in generating turn-by-turn navigation instructions. The following section describes several processes used to generate this intersection data, in which the mapping service receives vendor-provided junctions, identifies whether any sets of the received junctions should be consolidated into a single intersection, identifies pairs of road segments that should be joined together within an intersection, and generates angles for the intersection. Within this section, the term junction will be generally used to refer to vendor-provided information at which two path segments intersect, while the term intersection will refer to data generated from the junctions that represents where two or more roads meet in the real world. Thus, multiple junctions might be consolidated into one intersection, and junctions between two road segments that are actually just a continuation of a single road might not be considered intersections at all, in some embodiments.
  • The following represents pseudocode of some embodiments for generating intersection data for point intersections:
      • Identify all internal segments;
      • Identify all internal turn channels and mark them as internal segments;
      • For each internal segment:
        • Gather all contiguous internal segments;
        • Mark the gathered internal segments as processed;
        • Build an intersection from this collection of internal segments;
  • In addition to other data (e.g., locations of parks, waterways, businesses, etc.), the map data stores information about pathways (i.e., roads, walkways, bike paths, etc.). Each pathway, in some embodiments, is received from a map provider as a series of segments (e.g., road segments). For a given segment, in some embodiments the stored data includes start and end junctions for the segment, geometry data that defines the course taken by the path between the start and end junctions, a path characterization (or “form of way”), a direction of travel (which may, in some embodiments, involve a one-way flag), one or more names for the path (e.g., “I-405 S”, “San Diego Freeway”, etc.), a class that indicates the level of importance of the path, and a netclass (a connected graph of paths to which the path belongs). In some embodiments, the geometry information comprises a series of latitude/longitude vertices through which the path travels. The form of way attribute, in some embodiments, includes the following characterizations: single carriageway, dual carriageway, motorway, slip road, connector, walkway, stairs. Some embodiments may include additional characterizations.
  • FIG. 51 conceptually illustrates a process 5100 of some embodiments for determining path segments between sets of junctions that should be treated together as a single intersection. As shown, the process 5100 begins by receiving (at 5105) a junction between at least two path segments (e.g., road segments). In some embodiments, the mapping service receives (e.g., as precalculated data from a map vendor) a set of road segments and a set of junctions. Each road segment follows a path between two such junctions, and each junction references at least two road segments that enter and/or exit the junction. On the other hand, in some embodiments, the junctions are not received from the map data vendors and the mapping service traverses the path data to identify intersections between paths and analyzes these intersections in order to pretabulate the junctions.
  • The process then determines (at 5110) whether any of the path segments at the received junction are dual carriageways. As mentioned, a dual carriageway is a path characterization used in some forms of map data. Many roads that are divided (e.g., by a median, a double-yellow line, etc.) are received (and drawn) as two separate path segments, one for each direction. Each of the path segments is then marked with a direction of travel and as one-half of a dual carriageway. Because a user will typically think of an intersection of two roads that are both divided by medians as a single intersection (rather than four separate intersections), the junction generation process attempts to unify these four received junctions into a single intersection to present to a user for navigation purposes.
  • When none of the path segments are marked as dual carriageways, the process calculates (at 5115) the intersection branches using only the path segments specified in the received junction (i.e., the intersection will include only the one received junction). In some embodiments, the calculation of junction branches entails calculating the angle at which each of the segments specified for the junction leaves the junction location. The process then ends. FIG. 52 illustrates an example of such a junction 5200, also illustrating that there is no requirement that the path segments meet at right angles or that the paths continue in a straight line through the junction.
  • When at least one path segment specified for the received junction is a dual carriageway, the process determines (at 5120) whether there exists a cross-traffic turn off of a dual carriageway at the junction. A cross-traffic turn is a turn off of the dual carriageway in a direction that will cross through the matching half of the dual carriageway (i.e., the other direction of the road), assuming it exists. In the United States, a left turn is a cross-traffic turn. While the examples shown in this document involve right-handed driving (i.e., driving on the right side of the road), one of ordinary skill will recognize that the examples are equally applicable to left-handed driving areas (e.g., England) as well. FIG. 53 illustrates an intersection 5300 that includes two dual carriageway paths 5305 and 5306 and a one-way road 5310. At the junction 5315, there is no cross-traffic turn off of a dual carriageway, because the only options are a right turn off of the dual carriageway path 5305 or a left turn off of the one-way street 5310. When no such turn exists, the process 5100 stores (at 5125) the received junction while recognizing that it may still be part of a larger intersection, in order to determine whether to include the received junction with other received junctions (e.g., the junction 5320 between the one-way road 5310 and the dual carriageway path 5306) in a larger intersection. For instance, in the intersection 5300, the process will want to join the received junction 5320 with the received junction 5315 into a single larger intersection. The process then ends.
  • When a cross-traffic turn off of a dual carriageway exists at the junction (for instance, at junction 5320), the process moves (at 5130) in the direction of the cross-traffic turn until the next dual carriageway path is reached. In some embodiments, because the path segments start and stop at junctions, the next dual carriageway path will be reached at a different received junction (though not necessarily the next junction, if a road such as a left turn lane is received as a separate path segment). For instance, from intersection 5320, the process would traverse the path 5310 away from the junction 5320 until reaching the next dual carriageway, at junction 5315.
  • The process 5100 then determines (at 5135) whether the dual carriageway path reached at 5130 has a direction of travel in the opposite direction of the originating dual carriageway path. This, essentially, is a quick determinant of whether the second dual carriageway could be the matching path for the first dual carriageway (i.e., whether they are likely to be two sides of the same road). In most cases, this next dual carriageway will be the matching path, due to the nature of how roads are typically built.
  • In the case when the second dual carriageway is not in the opposite direction of the originating path, the process proceeds to 5125 to store the newly reached junction for later use in determining whether to include it with any other received junctions. For example, if the left turn off of path 5306 reached another dual carriageway with a downward direction of travel, then path 5306 could be assumed to not have a match in the data (as far as the junctions are concerned, at least), but the newly identified path might itself have a match.
  • On the other hand, if the two dual carriageways have opposite directions of travel, the process identifies and stores (at 5140) the segment traversed by the cross-traffic turn. In the example of FIG. 53, the segment from junction 5320 to junction 5315 would be stored. This segment will be used as part of additional junction consolidation processes in some embodiments. The process then ends.
  • The above process 5100, when applied to all the junctions within a map region, will generate a set of segments between dual carriageways. Some embodiments use these segments to link together received junctions and identify additional received junctions to include in a single intersection definition. The following represents pseudocode of some embodiments for identifying all such “internal” segments for a complex intersection:
      • For each segment that is a dual carriageway;
        • For each connection with cross-traffic turn where a path can be assembled to other side of intersection;
          • Mark all segments on the path to other side as internal segments;
  • This pseudocode includes a determination as to whether a path can be assembled to the other side of an intersection from a segment. The following includes pseudocode of some embodiments for such a determination:
      • Add first segment to path;
      • Get connections from last segment on path;
      • Iterate through each connection to either find a connection to other side or find connection that is best continuation;
        • If connection is other side, note success and end;
        • If no connection is other side and no connection is the best continuation, note failure and end;
        • Otherwise:
          • Add segment to end of path;
          • If path is too far, note failure and end;
          • If too many crossings, note failure and end;
          • Otherwise return to get connections for added segment and iterate through connections;
  • FIG. 54 conceptually illustrates a process 5400 for linking together several junctions into a single intersection and identifying the branches of the intersection. The process 5400 begins by receiving (at 5405) a set of intersecting segments between dual carriageways. These segments may be identified using a process such as that shown in FIG. 51, in some embodiments. The mapping service then groups together sets of such segments that intersect each other (i.e., at received junctions). FIG. 55 illustrates a commonly existing intersection 5500, between a dual carriageway with paths 5505 and 5506 and a dual carriageway with paths 5510 and 5511. The set of intersecting segments are shown in this figure as thicker lines.
  • The process then identifies (at 5410) all junctions and path segments that connect directly to the set of intersecting segments at junctions. That is, the set of intersecting paths intersect at junctions, but these junctions may contain additional path segments. For instance, in the example intersection 5500, the eight dual carriageway path segments that leave the intersection all intersect with the internal (thicker) path segments at the four junctions. Thus, the four junctions and eight external path segments are all included in the intersection.
  • FIG. 56, on the other hand, illustrates an intersection 5600 in which left-turn channels are defined as separate path segments. In this case, because the left-turn channels intersect the internal segments at junctions received in the initial map data, these channels are identified by the process 5400. The left-turn channels may be characterized in the map data as slip roads or single carriageways, in most cases.
  • The following represents pseudocode of some embodiments for identifying all turn channels to treat as “internal” to an intersection:
      • For each segment that is a dual carriageway;
        • For each connection with cross-traffic turn where a path can be assembled to internal segments;
          • Mark all segments on the path to the internal segments as internal segments themselves;
  • This pseudocode includes a determination as to whether a path can be assembled to the internal segments from a segment (e.g., a turn channel). The following includes pseudocode of some embodiments for such a determination:
      • Add first segment to path;
      • Get connections from last segment on path (i.e., segments connected to last segment at junction);
      • Iterate through each connection to either find either an internal segment or find connection that is best continuation;
        • If connection is an internal segment, note success and end;
        • If no connection is internal segment and no connection is the best continuation, note failure and end;
        • Otherwise:
          • Add segment to end of path;
          • If path is too far, note failure and end;
          • If too many crossings, note failure and end;
          • Otherwise return to get connections for added segment and iterate through connections;
  • Next, the process 5400 defines (at 5415) a new intersection as including all of the identified junctions and path segments, including those that directly intersect the initial set of path segments. In some embodiments, in the case illustrated in FIG. 56, the junctions where the left-turn channels leave their originating dual carriageway segments would be included as well as the left-turn channels that intersect the initial segments. In this situation, some embodiments identify the other junction (i.e., the start junction) for the slip road or single carriageway path segment, which will be where the path segment intersects with one of the dual carriageway path segments before entering the intersection. When the single carriageway path segment stays internal to a (presumed) pair of dual carriageway paths for a threshold distance (e.g., 1 km), some embodiments assume the path segment is a part of the road defined by the dual carriageway paths, and eliminate the junction from consideration.
  • When processing a slip road or other connector outside of the dual carriageways (e.g., the slip road 5705 shown in the intersection 5700 of FIG. 57), some embodiments do not treat the slip road as a path into the dual carriageway intersection. Instead, some embodiments identify the path characterization as a slip road and attempt to form a closed loop including the start and end junctions of the slip road. When this closed loop shares a common junction with the newly defined intersection (as will typically be the case), the slip road may be associated with the intersection but not treated as an internal path of this intersection. On the other hand, when the newly defined dual carriageway intersection has grown due to the presence of, e.g., left-turn channels, such that the slip road junctions are encompassed by the intersection now including the intersecting single carriageways (as for the slip road 5805 in the intersection 5800 of FIG. 58), some embodiments treat the slip road as internal to the newly defined intersection. In the description of the intersection, these left turn channels, slip roads, etc., will typically be eliminated, as a user generally will not want complex instructions, but will instead want an instruction of “make a right turn onto San Vicente Blvd” or something similar.
  • With the set of segments and junctions that form the intersection defined, the process needs to merge dual carriageways into single junction branches. The process 5400 next defines (at 5420) the set of all paths entering the intersection, and defines (at 5425) the set of all paths exiting the intersection. For a dual carriageway, which is a one-way path (half of a two-way road), the path will typically have an exit side and an entrance side. For purposes of merging, some embodiments treat each segment (the segment exiting the intersection and the segment entering the intersection) as separate paths. Single carriageways that are not internal to dual carriageways (e.g., the additional two-way path 5905 in the intersection 5900 of FIG. 59) will typically be treated as separate branches and are not part of the merging analysis in some embodiments.
  • Next, the process determines (at 5430) whether the set of entrance paths includes any unpaired dual carriageway paths. When no such paths remain in the set (or none existed in the first place), the process stores (at 5435) any unpaired dual carriageway left in the set of exit paths as separate branches of the junction. In general, this will happen in the case of mislabeled map data (the road is actually a one-way street) or merging criteria that are too strict (leaving a pair of entrance and exit paths unmerged).
  • When an unpaired entrance path exists, the process selects (at 5440) one of the entrance paths. The process then determines (at 5445) whether a potential match exists in the exit set. A potential match, in some embodiments, is a dual carriageway found by traversing the previously identified segment to the left (to the right, in the case of left-handed driving regions), or traversing the intersection in a clockwise fashion.
  • When no potential match exists (e.g., the next identified dual carriageway in the traversal is also an entrance path, or the exit set is empty), the process stores (at 5450) the entrance path as a separate branch of the intersection and then returns to 5430 to find the next unpaired entrance path. On the other hand, when a potential match exists, some embodiments determine (at 5455) whether the potential pair satisfies a set of dual carriageway match criteria. These are criteria, in some embodiments, to determine whether a pair of dual carriageways are actually the two sides of the same road. Some embodiments determine whether the two paths (1) are within a threshold distance (e.g., 25 m, 50 m, etc.) where the paths enter/exit the intersection, and (2) whether the angles at which the paths hit their junctions within the intersection is within a threshold range of each other (e.g., 5°, 10°, etc.). To calculate the angle, some embodiments use the vertex closest to the edge of the intersection (or the location of the junction at which the path segment intersects the other segments within the intersection) and a vertex located a particular predefined distance (e.g., 50 m) away. The process then calculates the angle off of North for the line between the two vertices.
  • In some embodiments, the mapping service additionally looks at the names of the paths to determine whether these match. When the names match, such embodiments may relax the geometry criteria for a matching pair (i.e., allow a greater distance between the paths or a greater difference in angles between the paths). Matching names might be, e.g., “CA-1 South” and “CA-1 North”, or if both paths include “Wilshire Blvd.” as one of their names. Some embodiments may also look at the road class data for confidence in matching dual carriageways.
  • If the two paths match, the process merges (at 5460) the paths into a single branch of the newly defined intersection. As indicated above, intersections are stored as a set of branches at different angles. For a merged path, some embodiments store the angle as the average of the angles of the two paths that make up the branch. FIG. 60 illustrates the reduction of an eight-path intersection 6000 into four branches, in which the angle of the right branch 6010 is at half the offset from horizontal as the right exit path 6005, because the right entrance path is on the horizontal. As shown conceptually, directions (entrance/exit) are not stored for intersection branches in some embodiments. The mapping service generates the routes using map data, which includes the intersections as well as directions of travel for the roads, so a route will not travel the wrong way on a branch of the intersection.
  • On the other hand, when the paths do not match, the process stores (at 5465) each of the paths as separate branches of the intersection. FIG. 61 illustrates the reduction of a different eight-path intersection 6100 into five branches. In this case, the dual carriageway paths 6105 and 6106 on the right side do not merge and are therefore treated as separate branches 6110 and 6111 of the reduced intersection. In this example, the angle at which each of these branches leaves the intersection is the angle that is stored for the branch (with no averaging). The process 5400 then returns to 5430 to determine whether any entrance paths remain. As stated, once the entrance path set is empty, the process proceeds to 5435, and subsequently ends.
  • The following represents pseudocode of some embodiments for generating the data for an intersection once the internal segments have been identified for the intersection (e.g., operations performed by some or all of process 5400):
      • Gather all external segments that touch internal segments for an intersection;
      • Identify external segments that are surrounded by internal segments in the intersection and mark them as internal;
      • Group together pairs of incoming and outgoing segments that represent same road;
      • Compute an outgoing angle for each pair and for each unpaired road;
      • Construct a template Intersection Pattern with one branch for each angle;
      • If pattern exists for previously generated intersection, use existing pattern to save space (refer intersection to existing pattern);
      • Else if pattern does not exist, create and store new entry for pattern;
  • As indicated, some embodiments store each intersection as a data structure. This data structure indicates the branches of the intersection and the angles at which the branches enter and/or exit the junction. FIG. 62 conceptually illustrates an example of such a data structure 6200 of some embodiments for a point type intersection. As shown, the intersection includes an intersection ID (which, in some embodiments is a unique identifier), a map data association, and a set of branches with angles and types. The map data association, in some embodiments, associates the intersection data structure with an actual location within the map. In some embodiments, this is simply a latitude/longitude point, but may also consist of other data in other embodiments (e.g., a list of the path segments or aggregate paths that meet at the intersection). Each branch includes a type and an angle. The type, in some embodiments, is an intersection type. Some embodiments define two intersection types: point and roundabout. However, other embodiments may include additional intersection types, such as traffic squares. Some embodiments store the intersection type as a property of the intersection rather than separately for each branch, but other embodiments recognize the possibility of an intersection partially being a roundabout but partially being a point intersection. The data structure 6200 includes four branches, at the cardinal directions of 0° (North), 90° (East), 180° (South), and −90° (West). In some embodiments, the intersection data structure also includes references to any junctions (i.e., data received from the map data provider) and path segments that are contained within the defined intersection. For a typical intersection of two dual carriageways, four junctions are referred to by such a data structure.
  • FIG. 63 illustrates a data structure 6300 of some embodiments for a roundabout intersection. Some embodiments provide specialized processing for roundabout intersection. The following represents pseudocode of some embodiments for generating intersection data for roundabout intersections:
      • Identify all roundabout segments;
      • For each roundabout segment:
        • Gather all contiguous roundabout segments;
        • Mark the gathered roundabout segments as processed;
        • Build a roundabout intersection from this collection of roundabout segments;
  • In some cases, the map data identifies a roundabout (e.g., as a form of way or through another indicator). This allows the mapping service intersection calculator to begin its specialized automated roundabout processing. Specifically, when performing roundabout processing, the mapping service attempts to identify pairs of flare connectors (i.e., the portions of a road that flare into and out of a roundabout). In some embodiments, the intersection calculator traverses the roundabout (e.g., in a counterclockwise fashion for right-handed driving) looking for an exit path that is followed, within a particular distance (e.g., angular distance), by an entrance path. The process then determines whether to combine these paths, looking at factors similar to those for merging dual carriageways at point intersections. For instance, the factors used might include whether the names are similar, whether the distance between the exit/entrance paths is small enough, and potentially other factors. As a result of this processing, when a random road intersects the roundabout in between what otherwise appears to be an entrance/exit combination, some embodiments treat this as three separate branches.
  • In order to calculate the angles of the branches, some embodiments determine where the branch intersects the roundabout, rather than the angle of approach of the road. For entrance/exit combinations, the process takes the average of the two paths. FIG. 64 conceptually illustrates the reduction of a roundabout intersection 6400 to intersection data. The top path, despite approaching at approximately a 30° angle off of North, is designated as a 0° branch—the user is primarily interested in the distance around the traffic circle for the intersections, rather than the angle at which they enter and exit. The other three branches are also designated cardinal directions, because their flares average out to these directions. The data structure 6300 shows the data structure for the roundabout junction 6400. Other embodiments, however, use the angle at which the paths enter or exit the roundabout, rather than the distance around the roundabout at which the paths intersect it.
  • The following represents pseudocode of some embodiments for generating the data for a roundabout intersection once the roundabout segments have been identified for the intersection:
      • For set of roundabout segments that form a simple loop:
        • Gather all non-roundabout segments that touch the loop, ordered by the direction of travel around the loop;
        • Group together pairs of consecutive roundabout exit/entry segments that represent same road;
        • Assign an angle to each pair and each unpaired segment;
        • Subtract the smallest angle from all angles (so smallest angle=0);
        • Construct a template intersection pattern with one branch for each angle;
        • If pattern exists for previously generated intersection, use existing pattern to save space (refer intersection to existing pattern);
        • Else if pattern does not exist, create and store new entry for pattern;
  • As indicated in the above examples of pseudocode, some embodiments perform additional compression when storing the intersections. The real world contains millions (or hundreds of millions) of individual intersections, but many of these intersections have the same configuration (especially when very small angular variations are tolerated). Thus, rather than storing separate data for each of the hundreds of millions of intersections, some embodiments utilize compression in storing the intersections. As each intersection is processed, some embodiments store a template pattern for that intersection. When additional intersections with the template pattern are identified, such embodiments store a reference to that pattern (while still creating a separate data structure, as the location information is different for two intersections that follow the same pattern).
  • 3. Modification of Junction Data for Navigation
  • The above section described the generation of complex intersection data, typically done as an offline process prior to route generation. However, at the time of route generation, some embodiments modify the intersection data for transmission to the user. The mapping service providing the route data modifies the angles to make them relative to the direction of entry and marks one of the branches as an exit branch.
  • FIG. 65 conceptually illustrates a process 6500 of some embodiments for modifying intersection data in order to provide navigation information for a route. As shown, the process begins by receiving (at 6505) a route for which to generate intersection information. As mentioned above, some embodiments generate one or more routes for each set of starting and ending locations requested by a user device. Each of these routes consists of a series of maneuvers at various path intersections (i.e., at road intersections).
  • As shown, with the route identified, the process 6500 selects (at 6510) the next intersection along the route. Some embodiments begin with the first intersection (i.e., the first maneuver a user following the route will make), starting from the start point of the route. Many routes involve long stretches along a particular road, going straight through numerous intersections (possibly including junctions of two road segments that are part of the same road and at which no other roads intersect). In some embodiments, the navigation instructions do not include information about the intersections at which no turning maneuver is made. Accordingly, the next intersection is actually the next intersection along the route at which a maneuver will be made.
  • The process then retrieves (at 6515) precalculated intersection data as a set of branches with associated angles. As described above, some embodiments store a data structure for each intersection, which lists the branches of the intersection along with angles for each branch. FIGS. 62 and 63 illustrate examples of such data structures, for both a point intersection and a roundabout intersection.
  • After retrieving the data structure for the selected intersection, the mapping service rotates the intersection definition to normalize the definition to the direction at which the route enters the intersection. Accordingly, the process 6500 identifies (at 6520) the entry branch of the intersection and sets the entry branch to a predetermined angle. Some embodiments set the direction of movement into the intersection as 0°, and therefore set the entry branch of the intersection to 180°.
  • The process then rotates the other branches of the intersection. As shown, the process selects (at 6525) a next branch of the intersection. In some embodiments, the branches and angles are stored in an array, list, or similar data structure, and the process traverses this data structure. The process sets (at 6530) the angle of the selected branch based on an angular distance from the entry branch. For example, if the entry branch was stored as 0° (i.e., pointing North), then a branch stored as 95° will be shifted 180° to −85°. In addition, the process determines (at 6535) whether the selected branch is the exit branch of the junction (i.e., the branch at which the route exits the intersection). In order for the turn-by-turn navigation instructions at the client mapping/navigation application to properly display the maneuvers, the device needs to know along which branch of the intersection the route exits. Thus, when the selected branch is the exit branch, the process 6500 marks (at 6540) the selected branch as such. The process then determines (at 6545) whether any additional branches of the intersection remain to be converted for the route. When additional branches remain, the process returns to 6525 to select the next branch of the junction. When all branches have been processed for the current intersection, the process 6500 determines (at 6560) whether additional intersections remain along the route that need to be modified. When additional intersections remain, the process returns to 6510 to select the next intersection. When the last intersection is modified, the process ends.
  • FIG. 66 illustrates a conceptual drawing of a route taken through an intersection 6600, a data structure 6605 for the intersection, and the modification of the data structure to create a new data structure 6610 for turn-by-turn navigation instructions. As shown, the route enters from the right side (the 90° branch) and exits the intersection at the bottom (the −162° branch). In the modified data structure, the entry branch has been rotated to 180°, causing a 90° rotation of the other branches. The branch at 18° rotates to 108°, the branch at −65° rotates to 25°, and the branch at −162° rotates to −72°. In addition to the rotation angles, the data structure 6610 has the last branch marked as the exit for the navigation. Some embodiments include a binary exit field, with the exit branch marked with a ‘1’ and all other branches marked with a ‘0’.
  • D. Generation of Land Cover Geometry
  • In addition to generating road geometry for map tiles, some embodiments also generate land cover geometry. Much like road segment data is received from various sources, so may data describing land cover (e.g., as a series of vertices that indicate the boundary of a particular land cover body). The land cover may include bodies of water (e.g., rivers, oceans, lakes, swimming pools, etc.), administrative bodies (e.g., boundaries of states, countries, cities, parks, etc.), area designations (e.g., rural/urban/suburban, desert/mountains/forest, etc.), or other data describing the land between roads. Initially, some embodiments use these coordinates to grow geometries for the land cover items.
  • After growing geometries for the land cover, some embodiments use various operations to resolve boundaries between the geometries. For example, when combining data from different sources, the location data indicating object boundaries may not align perfectly and therefore there may be either gaps between the object geometries or overlap of the geometries. Some embodiments use different operations for resolving boundaries between different geometries, depending on the types of objects. In addition, the land cover geometry processing uses the road segment data to fill in the land cover geometry and ensure that gaps are not left between the land cover and the roads. Some embodiments grow the land cover geometries outside of their marked boundaries towards the roads, stopping the geometries at road centerline locations. While this creates an overlap between the land cover geometry and road geometry, in some embodiments the client mapping applications include instructions to render road geometry on top of land cover geometry. The following subsections describe some of these different methods for resolving discrepancies or mismatches between various land cover boundaries.
  • 1. Conflating Land Cover to Roads
  • FIG. 67 conceptually illustrates a process 6700 that some embodiments of the invention perform for conflating land cover polygons to road polygons. In some embodiments the process of conflating land cover polygons is performed in order to resolve data mismatches that occur from receiving land cover polygon data and road polygon data from different data sources. The process of conflating land covers will be described with reference to FIG. 68, which illustrates one example for conflating land covers to road polygons in three stages 6801-6803.
  • As shown in FIG. 67, process 6700 receives (at 6705) a road polygon. The process 6700 then receives (at 6710) at least two land cover polygons. In some embodiments the road polygon and the land cover polygons are received from two different data sources, while in other embodiments they are received from the same data source. Stage 6801 in FIG. 68 illustrates an example of two such land cover polygons 6810 and 6820. In this example, different land cover types are illustrated by each land cover polygon. For instance, land cover 6820 can be a lake and land cover 6810 can be a park. However, in other embodiments land cover polygons 6810 and 6820 could be of the same type. Furthermore, the process may receive more than two land cover polygons, which are not illustrated for simplicity. First stage 6801 also illustrates an empty space in between the two land cover polygons. Since land covers represent all areas except roads, the empty space is assumed to represent the location of where a road normally runs. However, due to irregularity of the space between the two land covers 6810 and 6820, if a road is drawn between the two land cover polygon, there would be irregular empty space between the road and the land covers that are not visually appealing when the map is rendered on a user device. Process 6700, therefore, conflates the land covers to the road as described below.
  • Process 6700 draws (at 6715) the road polygon in the empty space between the two land cover polygons as illustrated by road polygon 6830 in stage 6801 of FIG. 68. In some embodiments this road polygon represents the road that is located between the two land cover polygons. In some embodiments a road may not fit cleanly in the center of the empty space. Portions of the road, or the entire road may overlap one or both polygons. For simplicity, process 6700 is described under the assumption that the road is located in the space between the land cover polygons.
  • Next, process 6700 grows (at 6720) the land cover polygons up to the road polygon. For instance, as shown in stage 6802 in FIG. 68, the process expands the left side of land cover polygon 6810 until the polygon reaches the right side of road polygon 6830. The process also expands the right side of polygon 6820 until it reaches the left side of road polygon 6830. In some embodiments when the road polygon does not lie entirely in the center space between the land cover polygons, the, process alternatively grows the land cover polygons to the center of the gap. In other embodiments, the land cover polygons grow past the road geometry, covering portions or all of the road geometry.
  • In order to perform this expansion of step 6720, the process, in some embodiments, rasterizes the polygons prior to expansion. By rasterizing the polygons, the process generates pixel data for the pixels within each land cover polygon. The conflation process uses this pixel data to fill in neighboring pixels with similar data. For instance, if an empty pixel is neighboring a pixel of a land cover polygon that is of a type representing a paved area, the empty pixel also becomes of a type representing the same paved area. The process grows the empty pixels in this manner until they reach road polygon 6830, which acts as a barrier to end the polygon expansion process.
  • Although FIG. 68 illustrates an example where only one road polygon is drawn, other embodiments include multiple road polygons representing more than one road between the two land cover polygons. In such instances, empty space may remain between two roads because the land cover polygons are not expanded into the space between the two roads (i.e., the roads act as barriers for polygon expansions).
  • When empty space remains between the two roads, process 6700 marks (at 6725) the empty space between the roads as filler. In some embodiments the marked fillers are interpreted and rendered according to different instructions on a client application. For instance, in some embodiments, the user device renders these empty spaces as road dividers. In other embodiments, the user device renders these empty spaces as green space, asphalt, etc.
  • After marking any empty space that may exist between two roads, some embodiments convert the newly grown pixels into vectors to reduce the number vertices from the land cover polygons and union of the grown pixels with the original received polygons from step 6710 of process 6700. The process then draws (at 6730) the road over the road polygon. The drawn road may also overlap the polygons next to the road polygon, in some embodiments. Third stage 6803 of FIG. 68 illustrates operation 6730 of process 6700 where the process draws a road 6840 over the road polygon between the two polygons 6820 and 6810. In this example road 6840 covers the road polygon and overlaps portions of polygons 6810 and 6820.
  • Next, the process optionally performs (at 6735) polygon optimization on certain land cover polygon types to reduce the number of vertices in the land cover polygon. In some embodiments this process involves removing certain land cover polygons of a particular type and drawing land cover polygons on a separate layer. For instance, this optimization technique could be performed on small bodies of water such as swimming pools (or ponds) that generate a large number of vertices within the polygons corresponding to the pool and the area around it. For instance, four swimming pool surrounded by a paved area are represented as four polygons to represent the pools themselves. In addition, the paved area is represented as a polygon with four holes in it. In some embodiments, the polygons corresponding to the swimming pools and their corresponding holes are removed and placed in a separate layer. The paved area is drawn and the pools are drawn over it. In this way, the number of points related to the pools is reduced.
  • 2. Conflating Boundaries Based on Reliability or Quality of Source Data
  • FIG. 69 conceptually illustrates a process 6900 that conflates boundaries between adjacent polygons received from two different sources in some embodiments. Process 6900 is performed in some embodiments to resolve mismatched boundary coordinates received from different sources where one data source is considered more reliable than the other. The process of conflating boundary coordinates will be described with reference to FIG. 70 and FIG. 71.
  • FIG. 70 illustrates two stages 7001 and 7002 of some embodiments of the invention that resolve identified gaps 7010, 7040, and 7060 by conflating boundary coordinates between adjacent polygons 7020 and 7030. FIG. 71 illustrates two stages 7101 and 7102 in some embodiments of the invention that conflate the boundary coordinates of polygons 7120 and 7130 around identified overlaps 7110 and 7140.
  • As shown in FIG. 69, the process 6900 receives (at 6905) two polygons for two different land cover types that are adjacent to each other. For instance, the two land cover types may be representative of oceans and parks. The process may also receive several other land cover types representative of other map features. Next, the process identifies (at 6910) any gaps and overlaps between the boundaries of the two polygons.
  • As shown in stage 7001 in FIG. 70, there are gaps 7010, 7040, and 7060 between polygons 7020 and 7030. As shown in FIG. 71, there are overlap areas 7110 and 7140 between polygons 7120 and 7130. Although illustrated as separate figures for simplicity, some embodiments of the invention may conflate the polygon boundary coordinates around both gaps and overlaps occurring between the same two polygon during the conflation process.
  • Referring back to FIG. 69, after identifying the gaps and overlaps between the polygon boundaries, process 6900 determines (at 6915) which polygon has boundary coordinates that came from a more reliable source, thus having more reliable boundary coordinates. For instance if polygon 7120 represents ocean and polygon 7130 represents a park and the vendor or the source that provides ocean polygons is considered a more reliable or a better quality source, the process resolves the overlaps (at 6920) in favor of the more reliable data. In some embodiments, the process resolves the overlaps in favor of data that represents a particular type of polygon. For instance in the above ocean/park example, the process may determine that ocean polygons are more reliable than park polygons and resolve the overlaps in favor of the more reliable ocean polygon data. Other embodiments resolve the overlaps in favor of polygons of a greater or lesser size. For instance, some embodiments resolve the overlaps in favor of the polygon with the greatest perimeter length or the largest surface area, while other embodiments resolve the overlaps in favor of the polygon with the shortest perimeter length or smallest surface area. As shown in stage 7102 of FIG. 71, the overlap areas 7110 and 7140 are removed by matching the boundaries of the less reliable polygon 7120 to align with the boundaries of the more reliable polygon 7130. In other words, the coordinates of the more reliable polygon 7130 are used to determine the boundary between the two regions.
  • In order to resolve gaps, for the polygon with less reliable boundary coordinates (or lower quality data), the process calculates (at 6925) a threshold value based on the shape of the polygon. In some embodiments the shape of the polygon is based on the area of the polygon divided by the perimeter of the polygon, multiplied by a scaled factor. When more than a predetermined number of boundary points on the polygon with less reliable coordinates are closer to the more reliable polygon than the threshold value, the process (at 6930) uses the boundary coordinates of the more reliable polygon and extends the less reliable region to join the more reliable region. Once the distance between the two polygon is more than the threshold, the two polygons are left separated. For instance, if polygon 7030 in FIG. 70 is from a more reliable source (or has better data quality), the gaps 7010 and 7060 (which in this example are less than the calculated threshold) are closed by extending the less reliable region 7020 boundaries to the boundaries of region 7030. In other words, the boundary coordinates of region 7030 is used for both regions in the areas of gaps 7010 and 7060. On the other hand, the distance between the two region in a portion of gap 7040 in this example is more than the calculated threshold. Gap 7040 is, therefore, only partially closed.
  • In these examples, gaps and overlaps are conflated in favor of the more reliable boundary data. However, other embodiments may conflate boundary coordinates around gaps and overlaps in other ways including conflation in favor of the polygons or boundary data with the most detail.
  • 3. Conflating Region Boundaries Based on Analysis of Border Data
  • FIG. 72 conceptually illustrates a process 7200 that is performed by some embodiments of the invention for resolving border conflicts between regions. The regions can be any land cover regions such as bodies of water, parks, building, etc. The regions can also be administrative regions such as states, cities, counties, international countries, etc. The process extracts the borders in order to resolve mismatches when two sets of data are given for a common border. Such mismatches may occur, for example, when regional border data for a common boundary is obtained from different sources. Process 7200 attempts to resolve the mismatch in favor of a single border.
  • As shown in FIG. 72, process 7200 receives (at 7205) polygons corresponding to different regions. The process then identifies (at 7210) an overlap between the regions. The process resolves the overlap by including (at 7215) the overlapping area in the region with the border that preserves the most border data points. In some embodiments step 7215 involves subtracting a first polygon from a second polygon or vice versa. Some embodiments resolve the overlap based on which of the aforementioned operations has more border data points, to preserve more border details.
  • Next, process 7200 determines (at 7220) if all overlapping areas have been examined. If not, the process returns to step 7210 to identify another overlapping area between different regions.
  • After all overlapping areas have been examined, process 7200 continues to step 7225 to identify a gap between adjacent regions. Some embodiments of the invention obtain a list of gaps between adjacent borders by taking the union of all regions and subtracting all regions where overlaps have already been examined.
  • Once the process identifies a gap between adjacent regions, process 7200 determines (at 7230) if the gap is between only two regions. If yes, the process uses (at 7235) the border of the region that preserves the most number of points along the boundary. Otherwise, the gap is between three or more regions. In that case the process uses (at 7240) the border of the region that has the longest border. However, in some embodiments, if the gap is between 4 or more states, the process may flag the gap for analysis by a human. The process then determines (at 7245) if all gaps have been examined. If no, the process returns to step 7225 to identify another gap. If yes, then the process ends.
  • FIG. 73 illustrates an example of resolving a border conflict between two adjacent regions 7350 and 7360 by performing process 7200. Although only two regions are illustrated by FIG. 73 for simplicity, process 7200 could be performed on a mismatched border between several regions. As illustrated, regions 7350 and 7360 share a common border 7390. However border conflicts exist between the two regions. First stage 7301 of FIG. 73 illustrates a blown out portion 7340 of the border 7390 between regions 7350 and 7360. The blown out portion 7340 illustrates examples of border conflicts such as an overlap 7310 and a gap 7330 that could be resolved by performing process 7200.
  • Second stage 7302 of FIG. 73 illustrates a blown out portion of how a border 7370 might look after process 7200 is performed on border 7390. Referring back to FIG. 72, process 7200 would first identify (at 7210) overlap 7310 and resolve the conflict by including (at 7215) the portion of the region that preserves the most border data points. In the example illustrated by FIG. 73, process 7200 determined that the border 7395 around region 7360 preserves more border data points and included that border as shown in stage 7302. Process 7200 then identifies (at 7225) that gap 7330 has to be resolved. The process attempts to remove the gap 7330 between regions 7350 and 7360 also by using (at 7235) the border that preserves more border data points. In the example illustrated by FIG. 73, process 7200 determined that for this portion of the border, the border 7397 around region 7350 preserved more border data points and included that border as shown in stage 7302. In some embodiments, some or all of the operations defined in processes 67, 69, and 72 are performed by one or more software modules.
  • E. Tile Generation
  • One of the last operations performed by the set of servers that generate the map tiles is the tile cut operation, which generates the map tiles and encodes the geometric and vector data in these tiles. In some embodiments, the set of servers defines a map in terms of a tile tree with multiple levels that correspond to multiple zoom levels for viewing the map. For instance, the tile tree data structure in some embodiments is a quadtree with twenty one levels that correspond to twenty one zoom levels for viewing the map. In the quadtree, each node is a map tile, and each non-leaf node has four child tile nodes.
  • The tile cut operation has several novelties. One novelty is the fast mechanism that it uses to associate each geometry that was generated for a map to one or more tiles in the tile quadtree. This fast mechanism in some embodiments uses distributed computing to quickly associate the large number of geometries in the map with the large number of map tiles. The task of determining whether each geometry should be associated with a tile is treated as a task independent of other similar tasks, each of which can be assigned to different computing resource in a distributed computing environment.
  • For instance, one computing resource can determine whether one geometry intersects one tile. If it does, then for each tile's children, a separate intersection operation is performed in order to determine whether the geometry intersects the child tile. A separate computing resource can perform each distinct intersection operation independently of the other computing resources. This process can be viewed as “throwing” a geometry down a tile quad tree, identifying each tile node that the geometry intersects, and then sending an intersected portion of the geometry to each child node of each intersected node to determine whether the child node intersects the geometry. The geometries that are identified for each tile node are then used in the tile cut process to generate the tile.
  • Another novelty relates to the fast mechanism that it uses to re-encode road vector data in the map tiles to remove unnecessary data. Again, the tile cut operation uses distributed computing to distribute this task of re-encoding the vector data. Each distributed task involves initially recording the road data (which may be overlapping) of each tile on the same canvas in order to merge overlapping road geometries. The task then involves re-vector encoding this data to generate vector data that is not duplicative.
  • This tile cut operation of some embodiments is further described in the U.S. Provisional Patent Application 61/657,872, entitled “Scalable and Efficient Cutting of Map Tiles,” filed Jun. 10, 2012; the concurrently filed U.S. patent application Ser. No. ______, entitled “Scalable Processing for Associating Geometries with Map Tiles”, having Attorney Docket No. APLE.P0414; and the concurrently filed U.S. patent application Ser. No. ______, entitled “Scalable and Efficient Cutting of Map Tiles”, having Attorney Docket No. APLE.P0425. The provisional application 61/657,872 and the above-mentioned concurrently filed non-provisional applications are incorporated herein by reference.
  • III. Client Side Generation of 3D Presentations
  • The mapping application of some embodiments use a variety of novel techniques to present a 3D presentation of a map while the map is being browsed or while the map is providing a navigation presentation. For instance, as mentioned above, the mapping application renders the 3D presentation from the vantage point of a virtual camera, and uses various methods for moving the virtual camera (i.e., moving the perspective rendering position) automatically in certain situations to achieve a desired 3D presentation. One such example occurs when the mapping application of some embodiments moves the position of the virtual camera from a perspective rendering position behind a current position of a moving device to a top-down view of the current position when the device is about to make a turn along a route. Another example is the zoom in/out animations that are provided, which show objects in the scene growing and shrinking with the zoom in operation and the zoom out operation.
  • Also, in some embodiments, the mapping application provides two different types of 3D presentations—an immersive 3D presentation and a non-immersive 3D presentation. The immersive presentation in some embodiments not only displays more geometries but also displays more details for the geometries that are displayed in the non-immersive presentation. The mapping application also provides smooth transitions between the non-immersive and immersive presentations.
  • To achieve such smooth transitions and generate other novel effects, the mapping application of some embodiments uses a novel image processing pipeline. This pipeline performs a variety of pre-load operations to download, retrieve and/or decompress map tiles that may be needed for a navigation presentation, to prepare its rendering pipeline for its rendering operations, and to prepare a duplicate pipeline to smoothly transition between the immersive and non-immersive 3D presentations.
  • Subsection A below describes the automatic movement of the virtual camera used to render the 3D presentation. Subsection B then describes further the immersive and non-immersive 3D presentations of the mapping application. Subsection C next describes the image processing pipeline of the mapping application, and its associated meshing building pipeline, virtual camera, and rendering engine.
  • A. Automated Virtual Camera Movement
  • As described above, the virtual camera is a conceptualization of the position in the 3D map that mapping application renders to generate a 3D map view. The following provides descriptions of several different examples of the automated movement of such a virtual camera.
  • 1. Virtual Camera Movement During Route Navigation
  • FIG. 74 conceptually illustrates an example of a virtual camera 7400 automatedly moving around a region of a 3D map 7435 based on a route navigation. FIG. 74 illustrates the movement of the virtual camera 7400 around the region of the 3D map 7435 at three different stages 7405-7415. In some embodiments, the mapping application performs the process 7500 described below by reference to FIG. 75 to render the 3D map views described in this figure. As shown in this figure, the region of the 3D map 7435 includes a road that runs over a bridge.
  • The first stage 7405 illustrates the virtual camera 7400 at a particular location and position in the 3D map 7435. In some embodiments, the point at which the virtual camera 7400 is focusing (i.e., the point at which a line projecting out of the front of the virtual camera intersects the road) in the 3D map 7435 is referred to as a point of focus. In some embodiments, the mapping application uses a point along the route that is a defined distance (e.g., 5 feet, 10 feet, 25 feet, 50 feet, etc.) ahead of the user's location (represented by a circle with a triangle on top in this example) as the virtual camera 7400's point of focus. The mapping application of some embodiments uses different distances ahead of the user's location along the route based on the user's traveling speed (e.g., longer distances when the user is traveling at faster speeds and shorter distances when the user is traveling at slower speeds).
  • In the first stage 7405, the virtual camera 7400's point of focus is a point along the ramp up the bridge that is a defined distance ahead of the user's location. An example rendered image of the 3D map 7435 from the virtual camera 7400's point of view at this stage 7405 is illustrated in the 3D map view 7420. The 3D map views 7420, 7425, and 7430 illustrated in this figure, as well as those shown in other figures within this section, do not include various UI controls and features (e.g., road signs, navigation signs, floating controls, etc.) so as to highlight the rendered map images.
  • The second stage 7410 shows the virtual camera 7400 at a different location and position in the 3D map 7435. In this example, the virtual camera 7400 has moved up because the virtual camera 7400's point of focus is elevated due to the height of the bridge. In addition, the virtual camera 7400 has moved towards the right to follow along the route navigation. From the first stage 7405 to the second stage 7410, the mapping application automatically moved the virtual camera 7400, rendered images of the 3D map from the virtual camera 7400's point of view along the path, and displayed the images on the device. An example rendered image of the 3D map 7435 from the virtual camera 7400's point of view at this stage 7410 is illustrated in the 3D map view 7425.
  • The third stage 7415 illustrates the virtual camera 7400 at another different location and position of the 3D map 7435. For this example, the virtual camera 7400 has moved down because the virtual camera 7400's point of focus is on the road and no longer on the bridge. In addition, the virtual camera 7400 has moved towards the right to follow along the route navigation. From the second stage 7410 to the third stage 7415, the mapping application automatically moved the virtual camera 7400, rendered images of the 3D map from the virtual camera 7400's point of view along the path, and displayed the images on the device. An example rendered image of the 3D map 7435 from the virtual camera 7400's point of view at this stage 7415 is illustrated in the 3D map view 7430.
  • In some embodiments, the mapping application detects a threshold amount of change in elevation, or a threshold rate of change in elevation, of the point of focus along the route. The mapping application of some such embodiments adds a delay to the positioning of the virtual camera's adjustment of the tracking in response to the position of the focus point along the route when the mapping application detects that the user's location along the route has decreased in elevation and one or both of the thresholds have been passed. In some embodiments, the mapping application maintains the height of the virtual camera (e.g., the position of the virtual camera long a z-axis) for a defined amount of time when the mapping application detects the decrease in the elevation of the user's location along the route. Adding a delay and maintaining height for a defined amount of time are techniques that each prevents the virtual camera from approaching the road too closely or, in some cases, colliding into the road. This way, the mapping application provides the user a better view of the map while traversing undulating roads.
  • FIG. 75 conceptually illustrates a process of some embodiments for animating map views during a route navigation. The mapping application of some embodiments performs the process 7500 at defined intervals (e.g., 0.5 seconds, 1 second, 3 seconds, 5 seconds, etc.). In some embodiments, the mapping application repeatedly performs the process 7500 while the mapping application operates in the route navigation mode.
  • The process 7500 begins by identifying (at 7510) a set of attributes for determining the virtual camera's position at the end of a time period. In some embodiment, the end of the time period is the time at which the mapping application receives the current location of the user and the beginning of the time period is the time at which the mapping application receives the previous location of the user. In some embodiments, the set of attributes includes data that is used to derive the position and orientation of the virtual camera.
  • In different embodiments, the process 7500 uses different sets of attributes. The following describes some or all attributes used by the process 7500 of some embodiments. For instance, the process 7500 of some embodiments uses the location of a point of reference (i.e., the user's location). The process 7500 of some embodiments uses the location of the point of focus of the virtual camera, which is used to determine which direction the virtual camera should face in some embodiments.
  • In instances where the user is off-route from the route navigation, the point of focus is a fixed distance ahead of the user along the user's direction of travel (if that can be determined) or a fixed distance north of the user when the user's direction of travel cannot be determined. In instances where the user is on-route with respect to the route navigation, the point of focus is a fixed distance ahead of the user along the route to allow the virtual camera to subtly peek around turns before the user actually turns.
  • Some embodiments limit the angle between (1) a vector defined from the point of reference and the point of focus and (2) a vector pointing towards the user's travel direction, to a defined maximum angle amount. For example, if the route turns a corner shortly ahead, the point of focus will be a point around the corner from the current location of the device. As turning the virtual camera to face that actual point could cause the virtual camera to directly face a building, the amount that the virtual camera turns to peek around the corner is limited so that the view of the direction of travel is partially shown at all times.
  • Another virtual camera position indicator that the process 7500 of some embodiments uses is a location of point of interest (e.g., the location of an upcoming intersection). In some embodiments, the process 7500 determines the virtual camera view style and uses this indicator to derive the position and orientation of the virtual camera. Examples of virtual camera view styles includes top-down centered, top-down forward, and rooftop. A top-down centered view style in some embodiments is where the virtual camera looks straight down on the user's location such that the user's location is positioned at the center of the screen. In some embodiments, a top-down forward view style is where the virtual camera looks straight down on the user's location such that the user's location is positioned towards the bottom of the display. A rooftop” view style in some embodiments is where the virtual camera is positioned behind the user's location and is pitched so that it is looking forward along the vector from the user's location to the point of focus. If the user is off-route from the route navigation or the user's direction of travel cannot be determined (e.g., when the user is parked), the virtual camera is set to a top-down centered view style. Otherwise, the view style is determined by whether the user has requested a 2D or 3D navigation mode. If the user has requested a 2D navigation mode, the view style is set to a top-down forward view style. If the user has requested a 3D navigation mode, the view style is set to a rooftop view style.
  • In some embodiments, the process 7500 determines the virtual camera's focus style and uses it to determine the position and orientation of the virtual camera. Examples of virtual camera focus styles include a cruise focus style and a hard focus style. In some embodiments, a cruise focus style is where the virtual camera is set to a preset height and pitch angle. A hard focus style in some embodiments is where the virtual camera is set to a height (e.g., in the top-down centered or top-down forward view styles) and/or pitch (e.g., in the rooftop view style) so that a given point-of-interest is displayed on screen (e.g., the virtual camera focuses in on the point-of-interest as the user approaches it).
  • Next, the process 7500 determines (at 7520) the position and orientation of the virtual camera based on the identified attributes. After determining the position and orientation of the virtual camera, the process 7500 identifies (at 7530) the locations of a set of reference points at the end of the time period based on the virtual camera's position and orientation. Examples of reference points include the position of the camera, the intersection between the virtual camera's forward vector and the ground, a defined point along the virtual camera's right vector, etc.
  • The process 7500 then identifies (at 7540) the locations of a corresponding set of previous reference points. In some embodiments, the mapping application maintains a history of the locations of the set of reference points, which are determined in the same manner as those identified by the process 7500 at 7520, that the process 7500 accesses.
  • Finally, the process 7500 renders (at 7550) an animated map view for the time period based on the sets of reference points identified at 7530 and 7540. To render the animated map view, the process 7500 of some embodiments uses cubic polynomials associated with each reference point. The process 7500 animates the map view by (1) traversing each of the virtual camera's reference point along its associated cubic polynomial during the animation while (2) rendering the virtual camera's view of the map.
  • Before rendering the animated map view, the process 7500 of some embodiments updates the cubic polynomial associated with a particular reference point when the reference point has changed with respect to its corresponding previous reference point. In some embodiments, the process 7500 updates the cubic polynomial with a cubic polynomial determined based on the location of a reference point, the location of the corresponding previous reference point, and two tangents based on the reference point and its corresponding previous reference point. In some embodiments, the process 7500 uses a scaled version of a vector that ends at the location of the reference point and starts from the location of the corresponding previous reference point, as one of the tangents. For the other tangent, the process 7500 of some embodiments uses another scaled vector that is determined in a similar manner as the first scaled vector except the vector ends at the location of the previous reference point and the location of its corresponding previous reference point. The process 7500 fits a cubic polynomial using these two tangents, the location of the reference point, and the location of the corresponding previous reference point and uses the fitted cubic polynomial as the reference point's current cubic polynomial.
  • 2. Virtual Camera Movement Around Intersections
  • FIG. 76 conceptually illustrates an example of a virtual camera 7600 automatedly maneuvering a turn in a 3D map 7650 during on a route navigation. FIG. 76 illustrates the movement of the virtual camera 7600 in the 3D map 7650 at three different stages 7605-7615. In some embodiments, the mapping application performs the process 7700 described below by reference to FIG. 77 to maneuver a turn. As shown, the region of the 3D map 7650 includes a road that abuts another road and a building on the right side of the T-junction.
  • The first stage 7605 illustrates the virtual camera 7600 at a particular location and position in the 3D map 7650. In some embodiments, the point at which the virtual camera 7600 is focusing (i.e., the point at which a line projecting out of the front of the virtual camera intersects the road) in the 3D map 7650 is referred to as a point of focus. In some embodiments, the mapping application uses a point along the route that is a defined distance (e.g., 5 feet, 10 feet, 25 feet, 50 feet, etc.) ahead of the user's location (represented by a circle with a triangle on top in this example) as the virtual camera 7600's point of focus. The mapping application of some embodiments uses different distances ahead of the user's location along the route based on the user's traveling speed (e.g., longer distances when the user is traveling at faster speeds and shorter distances when the user is traveling at slower speeds). For this example, the virtual camera 7600's point of focus is a point along the route ahead of the user's location.
  • In the first stage 7605 the virtual camera 7600's point of focus is a point ahead of the user's location on the road that the user is traveling along. The first stage 7605 also illustrates a corresponding top-down view 7620 of the virtual camera 7600 and the 3D map 7650. As shown, the point of focus in this example is indicated by a black circle located ahead of the user on the road that the user is traveling along. An example rendered image of the 3D map 7650 from the virtual camera 7600's point of view at this stage 7605 is illustrated in the 3D map view 7635. The 3D map view 7635 also shows the virtual camera's point of focus.
  • The second stage 7610 shows the virtual camera 7600 at a different location and position in the 3D map 7650. As shown in the second stage 7610, the virtual camera 7600 has moved to the right towards the intersection along the route navigation. To maintain focus on the point of focus, the virtual camera 7600 has also moved up (e.g., up along the z-axis) in order to provide a better view of the point of focus during the right turn in case it might be obstructed. For instance, when there are buildings near or at the intersection, the point of focus might be occluded by the buildings thereby preventing a view head of the corner of the turn.
  • In addition, the virtual camera 7600 at this stage has tilted downwards (e.g., decreased pitch) in order to maintain aim at the point of focus. The top-down view 7625 at the second stage 7610 shows that the virtual camera 7600 has rotated slightly to the right of the intersection (e.g., about the z-axis) because the point of focus is just to the right of the intersection. Thus, from the first stage 7605 to the second stage 7610, the mapping application has automatically moved the virtual camera 7600 forward along the route navigation (e.g., along the x-axis, y, axis-, or a combination of both x and y axes, etc.) towards the intersection, moved the virtual camera 7600 higher (e.g., up along the z-axis), and rotated (e.g., about the z-axis) the virtual camera 7600 towards the right of the intersection while maintaining focus on the focus point ahead of the user's location. An example rendered image of the 3D map 7650 from the virtual camera 7600's point of view at the second stage 7610 is illustrated in the 3D map view 7640.
  • The third stage 7615 shows the virtual camera 7600 at another different location and position in the 3D map 7650. Here, the virtual camera 7600 has moved to the right and is at the intersection along the route navigation. To maintain focus on the point of focus, the virtual camera 7600 has also moved up (e.g., up along the z-axis) and over the intersection in order to provide a better view of the point of focus while the user is making the right turn for the same or similar reasons mentioned above (e.g., obstruction or occlusion of the virtual camera 7600's view of the point of focus).
  • In the third stage 7615, the virtual camera 7600 has also tilted farther downwards (e.g., decreased pitch) to maintain the focus on the point of focus. The top-down view 7630 in the third stage 7615 shows that the virtual camera 7600 has rotated to the right (e.g., about the z-axis) since the point of focus is now past to the right turn of the intersection. As such, from the second stage 7610 to the third stage 7615, the mapping application has automatically moved the virtual camera 7600 forward along the route navigation (e.g., along the x-axis, y, axis-, or a combination of both x and y axes, etc.) to the intersection, moved the virtual camera 7600 higher (e.g., up along the z-axis), and rotated (e.g., about the z-axis) the virtual camera 7600 towards the right of the intersection while maintaining focus on the point of focus ahead of the user's location. An example rendered image of the 3D map 7650 from the virtual camera 7600's point of view at the third stage 7615 is illustrated in the 3D map view 7645.
  • FIG. 76 illustrates a point of focus in the top-down views of a 3D map and the rendered 3D map views of the 3D map for purposes of explanation and clarity. In some embodiments, the mapping application does not actually render the point of focus in the 3D map views and the 3D map does not contain an actual point that represents the focus point.
  • FIG. 77 conceptually illustrates a process 7700 of some embodiments for animating a map view during a turn of a route navigation. In some embodiments, the mapping application iteratively performs the process 7700 when the mapping application is traversing a route navigation. The mapping application of some embodiments performs the process 7700 at defined intervals (e.g., 0.5 seconds, 1 second, 3 seconds, etc.) while the mapping application is traversing a route navigation.
  • The process 7700 begins by identifying (at 7710) an upcoming intersection. In some embodiments, the process 7700 uses map data to identify the upcoming intersection along the route navigation.
  • Next, the process 7700 determines (at 7720) whether the navigation route has a turn at the upcoming intersection. The process 7700 of some embodiments determines that a navigation route has a turn at the upcoming intersection when the process 7700 identifies a threshold change in direction near or at the intersection or determines a change in street name on along the route navigation at the intersection. Additional and/or other techniques are possible.
  • When the process 7700 determines that there is not a turn at the next intersection, the process 7700 ends. Otherwise, process 7700 determines (at 7730) whether the turn angle is within a threshold angle (e.g. whether the curve deviated from being straight by more than some number of degrees). The threshold angle is defined differently for different embodiments. In some embodiments, the threshold angle is defined as a value under 45 degrees, a value between 45 and 90 degrees, larger than 90 degrees, etc.
  • If the process 7700 determines that the turn angle is within the threshold angle then the process 7700 ends. Otherwise, the process 7700 displays (at 7740) the map view in a top-down viewing mode. In some embodiments, a top-down mode is a viewing mode in which the virtual camera is above or “on top of” the scene and pointing either mostly or entirely downwards. In some embodiments the top-down viewing mode is referred to as a hard focus mode. The top-down viewing mode in some embodiments is a 2D mode. In some instances, the mapping application was already displaying the map view in the top-down mode. In such instances, the process 7700 continues in the viewing mode through the turn along the route navigation.
  • Next, the process 7700 determines (at 7750) whether the turn has been completed. The process 7700 determines that the turn has been completed when the user's location is a defined distance past the intersection. In some embodiments, process 7700 determines that the turn has been completed when the virtual camera's position has rotated an angle amount of the turn angle or a threshold angle range within the angle of the turn. When the process 7700 determines that that turn has not been completed, the process 7700 returns to 7750 to continue checking whether the turn has been completed.
  • When the process 7700 determines that that turn has been completed, the process 7700 displays (at 7760) the map view in the original viewing mode. That is, the process 7700 displays the map view in the viewing mode that the mapping application was displaying the map view before the turn was approached. The process 7700 then ends.
  • Although the process 7700 was described as using a top-down mode, in some embodiments otherwise similar or identical processes use a non-top-down mode that makes the turn at the corner easier to see than whatever mode the map had been displayed in before the approach to the corner.
  • 3. Virtual Camera Movement when Panning
  • FIG. 78 conceptually illustrates an example of a virtual camera 7800 panning around a 3D map 7835 during a route navigation. FIG. 78 illustrates the movement of the virtual camera 7800 around the region of the 3D map 7835 at three different stages 7805-7815. The mapping application of some embodiments performs the process 7900 described below by reference to FIG. 79 to pan the virtual camera 7800. As shown in this figure, the region of the 3D map 7835 includes a road and several building along the side of the road.
  • The first stage 7805 illustrates a top-down view of the virtual camera 7800 at a particular location and position in the 3D map 7835. In some embodiments, the point at which the virtual camera 7800 is focusing (i.e., the point at which a line projecting out of the front of the virtual camera intersects the road) in the 3D map 7835 is referred to as a point of focus. In some embodiments, the mapping application uses a point along the route that is a defined distance (e.g., 5 feet, 10 feet, 25 feet, 50 feet, etc.) ahead of the user's location (represented by a circle with a triangle on top in this example) as the virtual camera 7800's point of focus. The mapping application of some embodiments uses different distances ahead of the user's location along the route based on the user's traveling speed (e.g., longer distances when the user is traveling at faster speeds and shorter distances when the user is traveling at slower speeds).
  • In the first stage 7805, the virtual camera 7800's point of focus is a point along road a defined distance ahead of the user's location, as indicated by a circle in the 3D map 7835. An example rendered image of the 3D map 7835 from the virtual camera 7800's point of view at the first stage 7805 is illustrated in the 3D map view 7820.
  • The second stage 7810 shows a top-down view of the virtual camera 7800 at a different location and position in the 3D map 7835. As shown, the virtual camera 7800 has rotated towards the right (e.g., about the z-axis). In this example, the mapping application of some embodiments automatically rotated the virtual camera 7800 towards the right in response to a gesture input (e.g., a swipe left gesture) received through a touchscreen. An example rendered image of the 3D map 7835 from the virtual camera 7800's point of view at this stage 7810 is illustrated in the 3D map view 7825.
  • The third stage 7815 illustrates a top-down view of the virtual camera 7800 at another different location and position of the 3D map 7835. For this example, the mapping application has automatically rotated the virtual camera 7800 back towards the left after a defined amount of time (e.g., 0.5 seconds, 1 second, 2 seconds, 3 seconds, etc.). In some embodiments, the mapping application rotates the virtual camera 7800 back after a defined amount of distance traveled (e.g., 10 yards, 25 yards, half a mile, etc.) An example rendered image of the 3D map 7835 from the virtual camera 7800's point of view at the third stage 7815 is illustrated in the 3D map view 7830.
  • FIG. 79 conceptually illustrates a process 7900 of some embodiments for panning to the side of a map view based on gesture input. In some embodiments, the mapping application performs the process 7900 when the mapping application is in a route navigation mode and the mapping application receives a gesture through a touchscreen of a device on which the mapping application is executing.
  • The process 7900 begins by receiving (at 7910) a gesture for panning to the side. In some embodiments, a gesture for panning to the side includes a touch gesture received through a touchscreen (e.g., swiping the touchscreen to a side with a finger). Alternatively, or conjunctively, the gesture for panning to the side in some embodiments includes a multi-touch gesture (e.g., swiping the touchscreen to a side with multiple fingers).
  • Next, the process 7900 identifies (at 7920) a panning component of the panning gesture. The process 7900 of some embodiments identifies the horizontal component of the panning gesture as the panning component. In other embodiments, the process 7900 identifies a vector defined from a location at the initial touch of the gesture (e.g., the location at which a finger touches the screen) to the location at the end of the gesture (e.g., the location at which the finger no longer touches the touchscreen).
  • In some embodiments, the process 7900 limits the panning component of the panning gesture. For example, if the process 7900 determines (at 7930) that the panning component exceeds a threshold amount (e.g., the magnitude amount of the panning component exceeds the threshold amount), the process 7900 limits (at 7940) the panning component (e.g., reducing the magnitude of the panning component) to within a defined limit.
  • Based on the panning component, the process 7900 then pans (at 7950) a virtual camera that is being used to render 3D map views of the route along the route navigation. The process 7900 of some embodiments pans the virtual camera in a similar manner of panning the virtual camera described above by reference to FIG. 78. That is, the process 7900 rotates the virtual camera about the z-axis to pan the virtual camera.
  • Next, the process 7900 determines (at 7960) whether a defined amount of time (e.g., 0.5 seconds, 1 second, 2 second, 5 seconds, etc.) has elapsed. When the process 7900 determines that that the defined amount of time has not elapsed, the process 7900 returns to 7960 to continue checking for the amount of time to elapse. When the process 7900 determines that that the defined amount of time has elapsed, the process 7900 proceeds to 7970.
  • Finally, the process 7900 pans (at 7970) the virtual camera back to its original position. In some embodiments, the process 7900 pans the virtual camera in a similar manner of panning the virtual camera described above by reference to FIG. 78. In other words, the process 7900 rotates the virtual camera about the z-axis to pan the virtual camera.
  • 4. Virtual Camera Movement During Perspective Adjustments
  • Besides (or instead of) having the navigation application control the camera (e.g., turning from 3D to 2D when going around corners) some embodiments also allow the user to adjust the level of the camera. Some embodiments allow the user to make a command gesture with two fingers to adjust the distance (height) and angle of the camera. Some embodiments even allow multiple types of gestures to control the camera.
  • FIG. 80 conceptually illustrates a perspective adjustment feature provided by a mapping application of some embodiments. Specifically, FIG. 80 illustrates a virtual camera 8000 at three different stages 8005-8015 that show the adjustment of the virtual camera 8000's position in response to a perspective adjustment. As shown, FIG. 80 illustrates a location in a 3D map 8035 that includes four objects, which are two buildings and two intersecting roads.
  • The first stage 8005 shows the virtual camera 8000 at a first perspective position pointing downwards towards the 3D map 8035 at a first angle (e.g., 45 degrees) with respect to the horizon. In this position, the camera 8000 is pointing to a location that may be a stationary position of the device or of a location being explored, or a moving position in front of a moving location of the device in a case where the map is used for navigation. In some embodiments, the default position of the camera 8000 is to be at a particular orientation with respect to the current location, but this orientation can be modified when the user rotates the map. Rendering a 3D map view based on the virtual camera 8000's position results in the 3D map view 8025.
  • The second stage 8010 shows the virtual camera 8000 at a different second perspective position pointing at a lower perspective towards the 3D map 8035 at a smaller second angle (e.g., 30 degrees) with respect to the horizon. The stage 8010 also shows that a user has provided input to adjust the perspective of the view of the 3D map 8035 by touching two fingers on the screen and dragging the two fingers in an upward direction (e.g., a swipe gesture). The scene flattening out is accomplished by the virtual camera 8000 lowering and decreasing the viewing angle with respect to the horizon. Rendering a 3D map view using the virtual camera 8000 positioned at this angle results in a 3D map view 8030 in which the buildings and the roads are taller than their illustration in the first map view 8025. As indicated by the dashed-line version of the virtual camera 8000, the virtual camera 8000 moved farther downwards along arc 8050 while tilting (e.g., pitching) farther up.
  • The third stage 8015 shows the virtual camera 8000 at a different third perspective position pointing at a higher perspective towards a location (e.g., the virtual camera 8000's point of focus) on the 3D map 8035 at larger third angle (e.g., 80°) with respect to the horizon. The stage 8015 also shows that the user has provided input to adjust the perspective of the view of the 3D map 8035 by touching two fingers on the screen and dragging the two fingers in a downward direction (e.g., a swipe gesture). The scene dropping is accomplished by the virtual camera 8000 rising and increasing its angle with respect to the horizon. As shown at this stage 8015, in some embodiments, the mapping application flattens the buildings (e.g., reduces the z-axis component of the polygons to the ground level) in the 3D map 8035 when the virtual camera 8000 is positioned in a top-down or near top-down position so that 3D map views rendered using the virtual camera 8000 appear 2D. Rendering a 3D map view using the virtual camera 8000 positioned at the angle in the third stage 8015 results in a 3D map view 8040 in which the buildings appear smaller, flatter and the roads appear smaller than their illustration in the second map view 8030. As shown by the dashed-line version of the virtual camera 8000, the virtual camera 8000 moved farther upwards along arc 8050 while tilting (e.g., pitching) farther down.
  • In some embodiments, the virtual camera 8000 can be made to move in this manner when the mapping application receives input for adjusting the perspective for viewing the 3D map 8035. In some of these embodiments, the mapping application switches to a top-down mode (where the rendering position faces straight down) that produces 2D map views when the zoom level reaches a particular zoom out level.
  • FIG. 80 shows a virtual camera moving along a particular path along an arc. The mapping application of different embodiments moves the virtual camera along different paths when adjusting the perspective of the virtual camera. For instance, in some embodiments, the mapping application uses a particular arc similar to the arc shown in FIG. 80 except the particular arc is farther away and up (e.g., zooms out) as the virtual camera moves upwards along the arc and closer (e.g., zooms in) and down as the virtual camera moves downwards along the arc. In some embodiments, the mapping application uses a path for the virtual camera that flattens out horizontal as the virtual camera moves upwards along the arc. Other paths on which the virtual camera moves are possible in other embodiments.
  • While moving along one of the arcs, the virtual camera rotates to maintain a desired location on the map at the focal point of the camera. The desired location in some cases is a stationary location of the device or a stationary location that the user is browsing on the map. In other cases, the desired location is a moving location in front of the moving location of the device as the user is moving with the device.
  • FIG. 81 conceptually illustrates a process 8100 of some embodiments for adjusting the position of a virtual camera that is used for rendering a map view in response to a perspective adjustment. In some embodiments, the mapping application described above and below by reference to FIGS. 1-108 performs the process 8100 when the mapping application is in a map viewing mode (e.g., a location browsing mode, a navigation mode, etc.) and the mapping application receives a gesture through a touchscreen of a device on which the mapping application is executing.
  • The process 8100 begins by receiving (at 8110) a gesture for adjusting the perspective of a map view. In some embodiments, a gesture for adjusting the perspective of the map view includes a multi-touch gesture received through a touchscreen (e.g., simultaneously touching the touchscreen with multiple fingers), such as the ones described above by reference to FIG. 80. In this example, the process 8100 receives a two-touch swipe gesture.
  • Next, the process 8100 determines (at 8120) whether an angle based on touch points is within a threshold angle. In some embodiments, the angle is defined by (1) a first vector from the location of one of the touch points towards the location of the other touch point and (2) a second vector from the location of the one touch point towards a horizontal direction. The horizontal direction of some embodiments is based on the orientation of the device, while the horizontal direction of other embodiments is based on the orientation of the device's display.
  • When the process 8100 determines that the angle is within the threshold angle, the process 8100 ends. Otherwise, the process 8100 identifies (at 8130) a translation component of the received gesture. In some embodiments, the process 8100 identifies the translation component of the gesture by identifying an amount of vertical translation of the gesture's touch points.
  • The process 8100 then adjusts (at 8140) the perspective of the map view based on the identified translation. As explained above by reference to FIGS. 3-5 and 74-80, a virtual camera is used in some embodiments to render a map view. The process 8100 of some embodiments adjusts the perspective of the map view by adjusting the position and orientation of the virtual camera. In some embodiment, a downwards vertical translation causes the virtual camera's position to increase in height and decrease in pitch (e.g., point farther down) while maintaining the virtual camera's point of focus (e.g., the point at which the virtual camera's forward vector intersects the ground). Stated differently, the camera moves along an arc and rotates more downward as the camera moves upwards along on the arc.
  • Different embodiments use different coordinate spaces for a map. For example, the map of some embodiments uses a Mercator unit coordinate space. In such embodiments, the process 8100 adjusts the virtual camera's position with respect to the map in order to adjust the perspective of the map view. As another example, in some embodiments, the map uses a World Geodetic System (e.g., WGS 84) as the map's coordinate space. The process 8100 in such embodiments adjusts the map with respect to the virtual camera's position in order to adjust the perspective of the map view.
  • In some embodiment, an upwards vertical translation causes the virtual camera's position to decrease in height and increase in pitch (e.g., point farther up) while maintaining the virtual camera's point of focus (e.g., the point at which the virtual camera's forward vector intersects the ground). That is, the camera moves along an arc and rotates more upward as the camera moves downwards along on the arc. In different embodiments, the vertical translation causes different adjustments to the virtual camera's position. For instance, a downwards vertical translation may cause the virtual camera's position to decrease in height and to increase in pitch while maintaining the virtual camera's point of focus and an upwards vertical translation may cause the virtual camera's position to increase in height and decrease in pitch while maintaining the virtual camera's point of focus.
  • Finally, the process 8100 renders (at 8150) a map view for display based on the adjusted perspective of the map view. The process 8100 then ends.
  • As described above, the process illustrated in FIG. 81 shows an adjustment to a perspective of a map view based on gesture input. The process of some embodiments limits the range of movement of the virtual camera. When gesture input causes the virtual camera's position to exceed a defined range, the process of some embodiments modifies the virtual camera's position be within the defined range. In some such embodiments, the process renders the map view of virtual camera's position, even if the virtual camera's position exceeds the defined range, during the gesture input (e.g., fingers used for touch points are still touching the touchscreen). The process renders the map view of the virtual camera's position that is modified within the defined range when the gesture input is completed (e.g., fingers used for touch points are no longer touching the touchscreen). In some embodiments, when the gesture input is completed, the process displays an animation that “snaps” from the map view of virtual camera's position that exceeds the defined range to the map view of the virtual camera's position that is modified within the defined range. In some embodiments, such an animation and the limit feature may be referred to as an offset rubberbanding feature or effect.
  • As shown in FIG. 80, different virtual camera positions render different perspectives of a map view. Specifically, FIG. 80 shows the map view transitioning from a 3D map view to a 2D map view. At the different stages of the transition, the buildings appear to fall into the ground. Similarly, during a transition of the map view from the 2D view in the third stage 8015 to the 3D map view in the first stage 8005, the building would appear to rise out from the ground. In some embodiments, the mapping application scales the vertices of the building along the z-axis in order to cause the building to appear to rise and fall when the map view transitions between 2D-like map views and different perspectives of 3D map views. The following is an example of an equation used by the mapping application of some embodiments to scale a vertex along the z-axis:

  • new_scaled_vertex.z=scaled_vertex.z*u_scale
  • where scaled_vertex.z is the z component of a vertex, u_scale is a scale factor that determines an amount to scale, and new_scaled_vertex.z is the new scaled value of the z component of the vertex. In addition, when zooming in/out of the 3D map or moving around the 3D map, some embodiments interpolate the alpha values used to blend buildings in and out and interpolate scale values used to adjust the height of buildings.
  • As explained above, FIG. 80 shows several example perspective adjustment operations and the corresponding movement of a virtual camera in a 3D map that is used to render 3D map views of the 3D map. One of ordinary skill in the art will understand that any number of different perspective adjustments are possible. In addition, the mapping application of some embodiments performs perspective adjustment operations in response to additional and/or different types of input. For example, in some embodiments, dragging the two fingers down may decrease the perspective position of the virtual camera and dragging the two fingers up may increase the perspective position of the virtual camera.
  • While FIG. 80 illustrates a virtual camera moving along an arc in order to change the perspective position of the virtual camera, the mapping application of some embodiments moves the virtual camera along different arcs at different zoom levels (e.g., distances from a 3D map). FIG. 82 conceptually illustrates a virtual camera 8210 that is moveable along three different arcs 8215-8225 at three different zoom levels. As shown, FIG. 82 illustrates a location in a 3D map 8205 that includes two buildings and two roads that form a T-junction.
  • At zoom level 18, the lowest zoom level in this example, the virtual camera 8210 is movable along the arc 8215 for different perspective positions of the virtual camera 8210 pointing towards the 3D map 8205. In other words, the mapping application of some embodiments at this zoom level allows a user to adjust the perspective for viewing the 3D map 8205 within the range (e.g., an angular range of 20 degrees) that the virtual camera 8210 is moveable along the arc 8215.
  • When the virtual camera 8210 transitions from zoom level 19 (e.g., zooms out), the mapping application limits the range of perspective positions of the virtual camera 8200 to the range along the arc 8215. In some embodiments, the mapping application positions the virtual camera 8210 along at a position along the arc 8215 that corresponds to the position that the virtual camera 8210 was at along the arc 8220 at zoom level 19 before transitioning to zoom level 18. If the position of the virtual camera 8210 at the zoom level 19 exceeds the range of the arc 8215 (e.g., a position along the lower perspective end of the arc 8220) when transitioning from zoom level 19 to zoom level 18, the mapping application in some embodiments positions the virtual camera at the closest position possible. In other embodiments, the mapping application gradually moves the virtual camera 8210 towards the closest corresponding position on the arc 8215 while in a transition region between zoom levels 18 and 19 when transitioning from zoom level 19 to zoom level 18 to provide a smooth transition of the virtual camera 8210's movement from zoom level 19 to zoom level 18.
  • At the next zoom level 19, the virtual camera 8210 is movable along the arc 8220 for different perspective positions of the virtual camera 8210 pointing towards the 3D map 8205. As shown, in some embodiments, the mapping application at this zoom level allows the user to adjust the perspective for viewing the 3D map 8205 within the range (e.g., an angular range of 45 degrees) that the virtual camera 8210 is moveable along the arc 8220. Thus, the mapping application allows the virtual camera 8210 to move along a greater range at zoom level 19 compared to zoom level 18.
  • When the virtual camera 8210 transitions from zoom level 18 or zoom level 20 (e.g., zooms in or out), the mapping application restricts the range of perspective positions of the virtual camera 8200 to the range along the arc 8220. The mapping application of some embodiments positions the virtual camera 8210 along at a position along the arc 8220 that corresponds to the position that the virtual camera 8210 was at along the arc 8215 or 8225 at zoom level 18 or 20, respectively, before transitioning to zoom level 19. If the position of the virtual camera 8210 at the zoom level 20 exceeds the range of the arc 8220 (e.g., a position along the lower perspective end of the arc 8225) when transitioning from zoom level 20 to zoom level 19, in some embodiments, the mapping application positions the virtual camera at the closest position possible. The mapping application of other embodiments gradually moves the virtual camera 8210 towards the closest corresponding position on the arc 8220 while in a transition region between zoom levels 19 and 20 when transitioning from zoom level 20 to zoom level 19 to provide a smooth transition of the virtual camera 8210's movement from zoom level 20 to zoom level 19.
  • At the zoom level 20, the highest zoom level for this example, the virtual camera 8210 is movable along the arc 8225 for different perspective positions of the virtual camera 8210 pointing towards the 3D map 8205. That is, the mapping application in some embodiments at this zoom level allows the user to adjust the perspective for viewing the 3D map 8205 within the range (e.g., an angular range of 85 degrees) that the virtual camera 8210 is moveable along the arc 8225. Thus, the mapping application allows the virtual camera 8210 to move along a greater range at zoom level 20 than zoom levels 18 and 19. When the virtual camera 8210 transitions from zoom level 19 (e.g., zooms in), the mapping application limits the range of perspective positions of the virtual camera 8200 to the range along the arc 8225.
  • The above-described FIG. 82 shows an example of a virtual camera that is moveable along different arcs at different zoom levels that allow different ranges of perspective positions for the virtual camera. One of ordinary skill in the art will realize that the mapping application of different embodiments uses any number of different arcs with number ranges of perspective positions for the virtual camera at different zoom levels.
  • FIG. 83 conceptually illustrates a process 8300 of some embodiments for determining an arc along which a virtual camera is movable. In some embodiments, the mapping application described above and below by reference to FIGS. 1-108 in this application performs the process 8300 when a zoom level is adjusted (e.g., zoom in or zoom out) in a 3D viewing mode (e.g., a 3D navigation mode, a 3D map browsing mode, etc.).
  • The process 8300 starts by determining (at 8310) whether the current zoom level is adjusted to a new zoom level. In some embodiments, the process 8300 determines that the current zoom level is adjusted to a new zoom level when the process 8300 receives input to adjust the zoom level of a view of a 3D map (e.g., the types of input described below by reference to FIG. 85). When the process 8300 determines that the current zoom level is not adjusted, the process 8300 returns to 8310 to continue checking for an adjustment to a new zoom level.
  • When the process 8300 determines that an adjustment to a new zoom level is received, the process 8300 identifies (at 8320) an arc for the new zoom level. As described above, the mapping application of some embodiments uses different arcs at different zoom levels. As such, the process 8300 identifies the arc that is defined for the new zoom level.
  • Next, the process 8300 determines (at 8330) whether the arc for the new zoom level has a position that corresponds to the position of the virtual camera along the previous arc of the previous zoom level. The process 8300 of some embodiments determines that the arc for the new zoom level has a corresponding position when the position of the virtual camera along the previous arc is within the angular range of the arc for the new zoom level. Referring to FIG. 82 as an example, if the zoom level is transitioning from zoom level 19 to zoom level 18, the process 8300 determines that the arc 8215 for zoom level 18 has a corresponding position when the position of the virtual camera along the arc 8220 for zoom level 19 is within approximately the top third of the arc 8220.
  • Upon determining that the arc for the new zoom level has a corresponding position, the process 8300 identifies (at 8340) the corresponding position along the arc for the new zoom level as new position for the virtual camera. Otherwise, the process 8300 identifies (at 8350) the position along the arc for the new zoom level that is closest to the position of the virtual camera along the previous arc of the previous zoom level as the new position for the virtual camera. Referring to FIG. 82 for an example, if the position of the virtual camera is at the lower perspective end of the arc 8220, as shown in FIG. 82, when transitioning from zoom level 19 to zoom level 18, the process 8300 identifies the position of the virtual camera shown in FIG. 82 along the arc 8215 for zoom level 18 as the new position for the virtual camera.
  • Finally, the process 8300 positions (at 8360) the virtual camera at the identified new position along the arc for the new zoom level. The process 8300 then ends.
  • While FIGS. 82 and 83 describe a virtual camera that is moveable along different arcs at different zoom levels, some embodiments use a particular arc for a range of different zoom levels (e.g., an arc for zoom levels 10-13, an arc for zoom levels 14-16, etc.). In some embodiments, different ranges of zoom levels are defined to include the same or a different number of zoom levels.
  • As discussed above, in some embodiments, the mapping application uses a particular arc along which a virtual camera is movable within a particular defined angular range along the arc when the virtual camera is positioned at a particular zoom level. The mapping applications of some embodiments uses the following technique for moving the virtual camera along an arc.
  • FIG. 84 conceptually illustrates a feature provided by the mapping application of some embodiments for maintaining the position of a virtual camera within a defined range along an arc. In particular, FIG. 84 illustrates the virtual camera 8400 at three different stages 8405-8415 that show the virtual camera 8400's position maintained within a defined range of arc 8450. As shown in FIG. 84, a location in a 3D map 8435 includes two buildings and two roads forming a T-junction.
  • The first stage 8405 shows the virtual camera 8400 at a particular position along the arc 8450. As shown, the arc 8450 represents a defined range (e.g., angular range) within which the virtual camera 8400 is movable. The first stage 8405 also shows three positions 8455-8465 along the arc 8450 (e.g., perspective view angles). In this example, the mapping application moves the virtual camera 8400 along the arc 8450 between the high perspective end of the arc 8450 (e.g., the position along the arc 8450 when the virtual camera 8400 is most tilted downwards) and the position 8455 in a manner similar to that described above by reference to FIG. 80. Rendering a 3D map view of based on the virtual camera 8400's position in the first stage 8405 results in 3D map view 8425.
  • When the virtual camera 8400 passes the position 8455 while moving towards the low perspective end of the arc 8450, the mapping application reduces the speed (e.g., decelerates) that the virtual camera 8400 moves towards the low perspective end of the arc 8450 regardless of the input provided by a user. In some embodiments, the mapping application reduces the speed of the virtual camera 8400 at a constant rate while, in some embodiments, the mapping application reduces the speed of the virtual camera 8400 at an exponential rate. Additional and/or different methods for decreasing the speed of the virtual camera 8400 are used in some embodiments.
  • The second stage 8410 shows that the virtual camera 8400 has moved to a position along the arc 8450 at or near the low perspective end of the arc 8450. As shown, a user is providing input to adjust the perspective of the view of the 3D map 8435 by touching two fingers on the screen and dragging the two fingers in an upward direction (e.g., a swipe gesture). In response to the input, the mapping application moved the virtual camera 8400 toward the low perspective end of the arc 8450 while tilting the virtual camera 8450 upwards. When the virtual camera reaches the position 8465 along the arc 8450, the mapping application prevents the virtual camera 8400 from moving lower beyond the position 8465 while the user is continues to provide input to decrease the perspective of the view of the 3D map 8435 (e.g., the user continues to drag the two fingers upwards on the touchscreen).
  • In some embodiments, when the user stops to provide input to decrease the perspective of the view of the 3D map 8435 (e.g., the user lifts the two fingers off the touchscreen), the mapping application “bounces” or “snaps” the position of the virtual camera 8400 from the position 8465 up to the position 8460 along the arc 8450. As the mapping application is generating or rendering 3D map views of the 3D map 8435 based on the view of the virtual camera 8400 during the bounce or snap motion, the generated 3D map views provide a bounce animation that displays the 3D map view briefly bounce or snap down in order to indicate to the user that the perspective of the map view cannot be decreased any farther. Rendering a 3D map view using the virtual camera 8400 positioned at this angle results in a 3D map view 8430 in which the buildings and the roads are taller compared to the map view 8425.
  • The third stage 8415 shows the virtual camera 8400 after the mapping application bounced or snapped the position of the virtual camera 8400 to the position 8460 in response to the user ceasing to provide input. Different embodiments use different techniques for implementing the bounce or snap of the virtual camera 8400. For instance, the mapping application of some embodiments starts quickly accelerating the virtual camera 8400 along the arc 8450 for a defined distance or until the virtual camera 8400 reaches a defined speed. Then the mapping application decelerates the virtual camera 8400 for the remaining distance to the position 8460 along the arc 8450. Other ways to implement the bounce or snap effect are used in some embodiments. Rendering a 3D map view using the virtual camera 8400 positioned at the position 8460 along the arc 8450 in the third stage 8415 results in a 3D map view 8440 in which the buildings appear a little smaller and flatter and the roads appear a little smaller compared to the map view 8430.
  • As described above, FIG. 84 illustrates a technique for preventing a virtual camera from moving beyond the low perspective end of an arc. Alternatively or in conjunction with preventing the virtual camera from moving beyond the low perspective end of the arc, the mapping application of some embodiments utilizes a similar technique for preventing the virtual camera from moving beyond the high perspective end of the arc. In addition, FIG. 84 shows an example of a position along an arc at which to slow down a virtual camera, a position along the arc to prevent the virtual camera from moving past, and a position along the arc to which the virtual camera snaps or bounces back. Different embodiments define the positions any number of different ways. For instance, in some embodiments, the position along the arc at which to slow down the virtual camera is the same or near the position along the arc to which the virtual camera snaps or bounces back.
  • 5. Virtual Camera Movement During Zooming
  • Alternatively, or in conjunction with the perspective adjustment feature, the mapping application of some embodiments allows the user to zoom in and out of a view of a 3D map (e.g., by providing gesture input with two fingers). FIG. 85 illustrates a zoom adjustment feature provided by the mapping application of some embodiments. In particular, FIG. 85 illustrates a virtual camera 8512 at three different stages 8501-8503 that show the movement of the virtual camera 8512 in response to zooming adjustments. As shown, FIG. 85 shows a location in a 3D map 8510 contains two buildings and a two roads forming a T-junction.
  • In the first stage 8501, the shows a 3D map 8510 with a virtual camera 8512 at a particular position pointing towards the 3D map 8510. In this position, the camera 8512 is pointing to a location that may be a stationary position of the device or of a location being explored, or a moving position in front of a moving location of the device in a case where the map is used for navigation. Rendering a 3D map view of based on the virtual camera 8512's position results in the 3D map view 8514.
  • The second stage 8502 shows the virtual camera 8512 at a different zoom level position pointing towards the 3D map 8510. The stage 8502 shows that a user has provided input to increase the zoom level of the view of the 3D map 8510 by touching two fingers near each other on the screen of the device and moving the fingertips apart while the fingers are touching the screen (e.g., a spread gesture).
  • The zoom-in adjustment is accomplished by the virtual camera 8512 moving closer to the 3D map 8510 along a line 8550. In some embodiments, the line 8550 that the mapping application uses to move the virtual camera 8512 along is a line formed by the front of the virtual camera 8512 and the virtual camera 8512's point of focus. The mapping application of some embodiments moves the virtual camera 8512 along a line formed by the front of the virtual camera 8512 and a location in the 3D map 8510 based on the user's input to zoom into the view of the 3D map 8510.
  • Rendering a 3D map view using the virtual camera 8512 at this position results in a 3D map view 8524 in which the buildings and the roads appear closer than the position shown in the 3D map view 8514. As indicated by the dashed-line version of the virtual camera 8512, the virtual camera 8512 moved closer towards the 3D map 8510 along the line 8550.
  • The third stage 8503 shows the virtual camera 8512 at a different zoom level position pointing towards the 3D map 8510. In this stage 8503, the user has provided input to decrease the zoom level of the 3D map 8510 by touching two fingers far apart on the screen of the device and moving the fingertips closer together while the fingers are touching the screen (e.g., a pinch gesture).
  • The zoom-out adjustment is accomplished by moving the virtual camera 8512 moving farther away from the 3D map 8510 along a line 8555. In some embodiments, the line 8555 that the mapping application uses to move the virtual camera 8512 along is a line formed by the front of the virtual camera 8512 and the virtual camera 8512's point of focus. The mapping application of some embodiments moves the virtual camera 8512 along a line formed by the front of the virtual camera 8512 and a location in the 3D map 8510 based on the user's input to zoom into the view of the 3D map 8510.
  • Rendering a 3D map view using the virtual camera 8512 at this position results in a 3D map view 8534 in which the buildings and the roads appear farther than the position illustrated in the 3D map view 8524. As shown by the dashed-line version of the virtual camera 8512, the virtual camera 8512 moved farther from the 3D map 8510 along the line 8555.
  • As described above, FIG. 85 illustrates several example zoom adjustment operations and the corresponding movement of a virtual camera in a 3D map that is used to render 3D map views of the 3D map. One of ordinary skill in the art will realize that any number of different zoom adjustments are possible. Additionally, the mapping application of some embodiments performs zoom adjustment operations in response to additional and/or different types of input (e.g., tapping the screen, double-tap the screen, etc.).
  • FIG. 86 conceptually illustrates a process 8600 of some embodiments adjusting the position of a virtual camera that is used for rendering a map view in response to a zoom level adjustment. In some embodiments, the mapping application described above and below by reference to FIGS. 1-108 performs the process 8600 when the mapping application is in a map viewing mode (e.g., a location browsing mode, a navigation mode, etc.) and the mapping application receives a gesture through a touchscreen of a device on which the mapping application is executing.
  • The process 8600 starts by receiving (at 8610) a gesture for adjusting the zoom level of a map view. In some embodiments, a gesture for adjusting the zoom level of the map view includes a multi-touch gesture received through a touchscreen (e.g., simultaneously touching the touchscreen with multiple fingers), such as the ones described above by reference to FIG. 85. In this example, the process 8600 receives a two-touch pinch or spread gesture.
  • Next, the process 8600 determines (at 8620) a zoom location based on the received gesture. The zoom location in some embodiments is a location in the map to which the zoom level is adjusted towards (e.g., for zoom in adjustments) or from which the zoom level is adjusted away (e.g., for zoom out adjustments). In some embodiments, the process 8600 determines the zoom location by (1) identifying the locations of the initial two touch points of the gesture and (2) identifying the midpoint along a line formed by the locations of the two touch points as the zoom location. The process 8600 of some embodiments uses additional and/or different techniques for determining the zoom location. For instance, the process 8600 uses the center of the map view as the zoom location in some embodiments.
  • The process 8600 then determines (at 8630) a zoom amount based on the received gesture. The process 8600 of some embodiments determines the zoom amount based on a length difference between (1) a first line formed by the locations of the initial two touch points of the gesture (e.g., the locations at which the user touches a touchscreen with two fingers) and (2) a second line formed by the locations of the ending two touch points of the gesture (e.g., the locations at which the user lifts the two fingers off the touchscreen). In some embodiments, the process 8600 determines a positive zoom amount (e.g., a zoom-in adjustment) when the length of the second line is greater than the length of the first line whereas the process 8600 determines a negative zoom amount (e.g., a zoom-out adjustment) when the length of the second line is less than the length of the first line. The process 8600 of some embodiments determines that the zoom amount is zero (e.g., no zoom adjustment) when the difference between the length of the second line and the length of the first line is equal or within a threshold length amount. In some embodiments, the process 8600 employs additional and/or different techniques for determining the zoom amount.
  • Next, the process 8600 adjusts (at 8640) the zoom level of the map view based on the identified zoom location and zoom amount. As explained above by reference to FIGS. 3-5 and 74-80, a virtual camera is used in some embodiments to render a map view. The process 8600 of some embodiments adjusts the zoom level of the map view by moving the position of the virtual camera (1) along a line formed by the front of the virtual camera and the zoom location and (2) by an amount based on the zoom amount.
  • Finally, the process 8600 renders (at 8650) a map view for display based on the adjusted zoom level of the map view. The process 8600 then ends.
  • 6. Virtual Camera Movement During Rotation
  • FIG. 87 conceptually illustrates a rotation operation of a 3D map view according to some embodiments of the invention. Specifically, FIG. 87 illustrates the rotation operation at two different stages 8705 and 8710. In some embodiments, the mapping application performs the process 9000 described below by reference to FIG. 90 to perform the rotation operation.
  • The first stage 8705 shows a 3D map view 8715 of a diagonal intersection of two roads and three buildings near the intersection. As shown, the three buildings are located at the top and sides of the diagonal intersection in the 3D map view 8715. The first stage 8705 also shows that a user is performing a gesture to rotate the 3D map view 8715. As shown, the user has touched two locations near the center of the 3D map view 8715 on the touchscreen using two fingers and has rotated the two locations in a clockwise direction.
  • The second stage 8710 illustrates the corresponding movement of a virtual camera 8700 around a 3D map 8725, which is used to render the 3D map view 8715, in response to the rotation gesture illustrated in the first stage 8705. In this example, the rotate gesture was received near or at the intersection of the two roads. As shown, the mapping application has moved the virtual camera 8700 from the left side of the 3D map 8725 towards the bottom of the 3D map 8725 by rotating the virtual camera 8700 about a z-axis located at or near the center of the rotation gesture. A 3D map view 8720 shows an example rendering of the 3D map 8725 after the rotation of the virtual camera 8700. As shown, the 3D map view is now rotated such that the three buildings and the roads are rotated in a clockwise direction in response to the clockwise rotate gesture shown in the first stage 8705.
  • While FIG. 87 shows a rotate gesture performed near or at the center of the 3D map view, rotate gestures may be performed at any location in the displayed 3D map view. In some embodiments, the mapping application rotates the 3D map based entirely or in part on the location of the rotate gesture. For instance, if a rotate gesture is performed in the upper right corner of the 3D map view, the mapping application of some embodiments rotates the virtual camera about a z-axis located at or near the location in the 3D map that corresponds to the location of the rotate gesture.
  • In some embodiments, the mapping application provides a position indicator feature that when activated repositions the 3D map view at the user's location (e.g., the location of the device in the 3D map). The mapping application of some such embodiments performs a rotation of the 3D map view differently when it is performed subsequent to an activation of the position indicator feature.
  • FIG. 88 conceptually illustrates a rotation operation of a 3D map view after an activation of such a position indicator feature according to some embodiments of the invention. In particular, FIG. 88 illustrates the rotation operation at two different stages 8805 and 8810.
  • The first stage 8805 shows a 3D map view 8815 of a diagonal intersection of two roads and three buildings near the intersection. As shown, the three buildings are located at the top and sides of the diagonal intersection in the 3D map view 8815. The first stage 8805 shows the 3D map view after a user has activated the position indicator feature that caused the mapping application to reposition the 3D map view at the user's location, which is represented by a circle in this example. In addition, the first stage 8805 shows that the user is performing a gesture to rotate the 3D map view 8815 in the upper portion of the 3D map view 8815. As shown, the user has touched two locations in the upper portion of the 3D map view 8815 on the touchscreen using two fingers and has rotated the two locations in a clockwise direction.
  • The second stage 8810 illustrates the corresponding movement of a virtual camera 8800 around a 3D map 8825, which is used to render the 3D map view 8815, in response to the rotation gesture illustrated in the first stage 8805. In this example, the rotate gesture was received in the upper portion of the 3D map view 8815 behind the middle building after the position indicator feature was activated.
  • In some embodiments, the mapping application rotates the 3D map about the user's location when the mapping application receives a rotate gesture after the position indicator feature is activated. The mapping application of some embodiments performs the rotate operation illustrated in FIG. 88 only when the mapping application receives a rotate gesture after the position indicator feature has been activated and the mapping application has not received any intervening non-rotate gestures. In some embodiments, the mapping application performs the rotate operation illustrated in FIG. 88 for a defined amount of a time after the position indicator feature is activated and then reverts to the rotate operation illustrated in FIG. 87.
  • As shown in the second stage 8810, the mapping application has moved the virtual camera 8800 from the left side of the 3D map 8825 towards the bottom of the 3D map 8825 by rotating the virtual camera 8800 about a z-axis located at or near the user's location, which is indicated by a black dot, at the intersection of the two roads. A 3D map view 8820 shows an example rendering of the 3D map 8825 after the rotation of the virtual camera 8800. As shown, the 3D map view is now rotated such that the three buildings and the roads are rotated in a clockwise direction about the user's location in response to the clockwise rotate gesture shown in the first stage 8805.
  • The above-described FIGS. 87 and 88 illustrate rotating a 3D map while in viewing a 3D map in a 3D perspective view. In some embodiments, the mapping application also allows a user to rotate the 3D map while viewing the 3D map in a 2D perspective view. FIG. 89 conceptually illustrates a rotation operation of a 3D map view from a 2D perspective view of the 3D map according to some embodiments of the invention. In particular, FIG. 89 illustrates at three different stages 8905-8915 the rotation operation along with an inertia effect for the rotation operation. In some embodiments, the mapping application performs the process 9000 described below by reference to FIG. 90 to perform the rotation operation.
  • The first stage 8905 shows a 3D map view 8920 of a 3D map. As shown, the 3D map view 8920 includes several streets running in a parallel or perpendicular direction. The first stage 8905 also shows that a user is providing input to rotate the 3D map view 8920. Specifically, the user is performing a gesture to rotate the 3D map view 8920 by touching two fingers at two locations on the touchscreen and rotating the two fingers in a clockwise direction, as indicated by two arrows.
  • The second stage 8910 shows the 3D map immediately after the user has completed the input to rotate the 3D map. For this example, the user completed the input by lifting the two fingers off the touchscreen of the device. In addition, the second stage 8910 shows a 3D map view 8925 of the 3D map rendered by the mapping application. As shown, the mapping application has rotated the 3D map in a clockwise direction from the 3D map view 8920 to the 3D map view 8925. The streets shown in the first stage 8905 have rotated approximately 45 degrees in the clockwise direction.
  • The mapping application of different embodiments utilize different methods to implement an inertia effect for a rotation operation. For instance, in some embodiments, the mapping application determines an angular velocity of the user's input at or near the instance at which the user lifts the fingers from the touchscreen based on one of the fingers or an average of both of the fingers. The mapping application uses the angular velocity to determine an angle amount for the inertia effect and determines the manner at which the virtual camera used to view the 3D map decelerates (e.g., constant, exponential, logarithmic, etc.) the angular velocity to rotate the determined angle amount. In some embodiments, the mapping application renders and displays an animation of the inertia effect (e.g., a decelerating rotation of the 3D map from the 3D map view 8925 that rotates the 3D map the determined angle amount). The mapping application of some embodiments does not implement the inertia effect. Rather, the inertia effect is implemented by a framework of an operating system on which the mapping application operates.
  • The third stage 8915 illustrates the 3D map after the mapping application has rendered and displayed the animation of the inertia effect. As shown, a 3D map view 8930 of the 3D map rendered by the mapping application is displayed. In the third stage 8915, the mapping application has rotated the 3D map farther clockwise after the user completed the input in the second stage 8910. As shown, a 3D map view 8930 in the third stage 8915 shows the streets rotated farther clockwise from the streets shown in the 3D map view 8925.
  • FIG. 90 conceptually illustrates a process 9000 of some embodiments for rotating a map view based on gesture input. In some embodiments, the mapping application performs the process 9000 when the mapping application is in a map viewing mode (e.g., a location browsing mode, a navigation mode, a 2D viewing mode, a 3D viewing mode, etc.) and the mapping application receives a gesture through a touchscreen of a device on which the mapping application is executing.
  • The process 9000 starts by receiving (at 9010) a gesture for rotating the map view. In some embodiments, a gesture for rotating the map view includes a multi-touch gesture received through a touchscreen (e.g., simultaneously touching the touchscreen with multiple fingers). In this example, the process 9000 receives a two-touch rotate gesture.
  • Next, the process 9000 identifies (at 9020) a rotation component of the received gesture. The process 9000 of some embodiments identifies the rotation component of the gesture by identifying an amount of rotation of the gesture's touch points. For instance, in some such embodiments, the process 9000 identifies the amount of rotation of the gesture's touch points by (1) determining a first vector from the initial location of one touch point to the initial location of the other touch point, (2) determining a second vector from a second location of the one touch point to a second location of the other touch point, and (3) determining a rotation direction based on the initial locations of the touch points and the second locations of the touch points.
  • The process 9000 then determines (at 9030) whether the amount of rotation is within a threshold amount. When the process 9000 determines that the amount of rotation is not within the threshold amount, the process 9000 ends. Otherwise, the process 9000 determines (at 9040) an axis of rotation based on the gesture. In some embodiments, the process 9000 determines the axis of rotation by (1) identifying a point along a vector from the initial location of one touch point to the initial location of the other touch point and (2) determining a point on map view that corresponds to the point along the vector (e.g., the point on the map that coincides with the point along the vector). The process 9000 uses the determined point on the map view as the location of an axis (e.g., a z-axis) about which the map view is rotated.
  • Next, the process 9000 then adjusts (at 9050) the map view based on the axis of rotation and the amount of rotation. In some embodiments, the process 9000 adjusts the map view by rotating the map view about the determined axis of rotation by the determined amount of rotation in the determined rotation direction. Different embodiments use different coordinate spaces for a map. For example, the map of some embodiments uses a Mercator unit coordinate space. In such embodiments, the process 9000 adjusts the virtual camera's position with respect to the map in order to adjust the map view. As another example, in some embodiments, the map uses a World Geodetic System (e.g., WGS 84) as the map's coordinate space. The process 9000 in such embodiments adjusts the map with respect to the virtual camera's position in order to adjust the map view.
  • Finally, the process 9000 renders (at 9060) the adjusted map view for display on the device. In some embodiments, the rendered map view is an image that represents the adjusted map view. Then the process 9000 ends.
  • The FIGS. 87-90 described above show various examples of rotate operations performed on a 3D map. In some embodiments, the 3D map is rotatable at a defined range and/or set of zoom levels. For example, in some embodiments, the mapping application allows the 3D map to be rotated at a defined number of the highest zoom levels (e.g., zoom levels 10-20) and prevents the 3D map from being rotated at the remaining lower zoom levels (e.g., zoom levels 1-10). In some such embodiments, the mapping application does not generate instructions to rotate the 3D map when the mapping application receives input to rotate the 3D map at a zoom level that is defined to not allow rotation operations. In other such embodiments, the mapping application generates instructions to rotate the 3D map when the mapping application receives input to rotate the 3D map at a zoom level that is defined to not allow rotation operations, but the mapping application simply ignores the instructions. One of ordinary skill in the art will realize that the zoom levels at which rotate operations are allowed to be performed on a 3D map may be defined any number of different ways in different embodiments.
  • B. Immersive and Non-Immersive Viewing Modes
  • Many of the figures described above and below illustrate a mapping application that provides a turn-by-turn navigation feature. In some embodiments, the mapping application provides several viewing modes for such a navigation feature. For instance, the mapping application of some embodiments provides an immersive viewing mode and a non-immersive viewing mode. In some embodiments, these two viewing modes are for viewing different 3D maps of the same geographical region. That is, one 3D map that is viewable using the immersive viewing mode and another 3D map that is viewable using the non-immersive viewing mode are 3D maps of the same geographic region. However, the immersive and non-immersive viewing modes of some embodiments are not limited to the turn-by-turn navigation feature. For instance, both the immersive and non-immersive viewing modes may be available in a map browsing mode (i.e., when not using navigation). Furthermore, some embodiments utilize the immersive viewing mode for the turn-by-turn navigation mode and the non-immersive viewing mode for the map browsing mode.
  • In some embodiments, the non-immersive and immersive viewing modes are viewing modes for viewing different 3D maps that have different constructs and/or geometries. For instance, the non-immersive viewing mode of some embodiments is for viewing a 3D map that is described by building tiles and road tiles. In some embodiments, a building tile contains polygon data (e.g., a polygon of the footprint of building and a height value of the building) for each of the buildings located in the region of the 3D map that the building tile represents. A road tile, in some embodiments, stores information about the various roads and land that are located in the region of the 3D map that the road tile represents. In some embodiments, the roads are defined by road vectors that represent the center of roads (e.g., centerlines) and the land is defined by polygon data.
  • The immersive viewing mode of some embodiments is for viewing a 3D map that is described by building tiles and navigation tiles. In some embodiments, the same building tiles that are used for the non-immersive viewing mode are used for the immersive viewing mode while, in some embodiments, building tiles used for the immersive viewing mode are different (e.g., the immersive building tiles include higher resolution polygon data for the buildings).
  • In some embodiments, a navigation tile includes polygon data for roads and polygon data for the land. By using polygon data to define roads, the navigation tiles can be defined more richly. For example, the roads appear 3D and/or appear as asphalt, curbs may be defined along the sides of streets, shadows can be specified for overpasses and bridges, etc. However, the navigation tiles require more information to describe the roads compared to road tiles, in some embodiments.
  • In some embodiments, stylesheet data, which is described in more detail below, is used to specify the appearance of constructs in the 3D map (e.g., buildings, streets, highways, land cover, foliage, labels, shadows, road curbs, etc.). For example, stylesheet data may specify the textures to apply to the different constructs, the color of the textures that are applied to the constructs, etc. In some embodiments, the stylesheet data is used to specify the textures for roads in order for the roads to appear like asphalt.
  • As mentioned above, both viewing modes use the same building tiles to render buildings for the viewing mode in some embodiments. The stylesheet data in some embodiments defines different styles (e.g., different textures, colors, levels of details etc.) for the buildings in the different viewing modes. For instance, in some embodiments, buildings in the non-immersive viewing mode are styled as gray and the outlines of city blocks have sharp corners. The same buildings in the immersive viewing mode of some embodiments are styled as light gray or white and the outlines of city blocks have rounded corners. Additional and/or different constructs may be styled differently for the different viewing modes in some embodiments. For instance, some embodiments specify different textures for the same buildings in different viewing modes.
  • In addition, style sheet data may specify different styles for the same or similar elements in the 3D map at different zoom levels. For instance, some embodiments specify simple textures for buildings at low zoom levels because the buildings are farther away and details may be difficult to notice or not noticeable at all. For higher zoom levels, some embodiments specify more detailed styling for buildings, such as defined shapes of building rooftops (as opposed to flat rooftops for all buildings).
  • In addition, the non-immersive and immersive viewing modes may be defined for viewing 3D maps at different ranges of zoom levels. For example, the non-immersive viewing mode of some embodiments is defined for viewing a 3D map at zoom levels 0-14 while the immersive viewing mode of some embodiments is defined for viewing the 3D map at zoom levels 15-21. The viewing modes may be defined to view any number of different zoom levels in different embodiments. In some instances, the range of zoom levels of the immersive viewing mode are defined as higher zoom levels than, lower zoom levels than, the same zoom levels as, or zoom levels that overlap with the zoom levels defined for the non-immersive viewing mode. For example, in some embodiments, the non-immersive viewing mode is defined for viewing at all zoom levels (e.g., zoom levels 0-21) while the immersive viewing mode is defined for a subset of high zoom levels (e.g., zoom levels 15-21).
  • A zoom level, in some embodiments, is a defined range of distances from the 3D map. For instance, a first zoom level may be defined as 6-10 distance units (e.g., feet, yards, meters, etc.) from the 3D map along the z-axis, a second zoom level may be defined as 11-15 distance units from the 3D map along the z-axis, a third zoom level may be defined as 16-20 distance units from the 3D map along the z-axis, etc. One of ordinary skill will recognize that zoom levels may be defined to include any number of different ranges of distances using any number of different distance units. In some embodiments, a zoom level is a defined range of distances from a 2D map, (e.g., a 2D version of the 3D map).
  • In some embodiments, a map service provider (e.g., a map server) generates and provides different sets of 3D map tiles of the 3D map for different zoom levels. For instance, the map service provider generates a set of 3D map tiles for a zoom level 0, a set of 3D map tiles for a zoom level 1, a set of 3D map tiles for a zoom level 2, etc. (e.g., for the non-immersive viewing mode). In some embodiments, the map service provider generates only one set of 3D map tiles of the 3D map (e.g., for the immersive viewing mode). The mapping application of some such embodiments renders 3D map views of the 3D map at different zoom levels by modifying (e.g., scaling up and/or down) the data in the 3D map tiles (e.g., vertices, polygons, etc.).
  • In some embodiments, the different sets of 3D map tiles that the map service provider generates for the different zoom levels have different levels of detail. For instance, the set of 3D map tiles generated for the highest zoom level include high resolution 3D constructs (e.g., the 3D constructs include more vertices) to more accurately represent the constructs. The set of 3D map tiles generated for the lowest zoom levels include low resolution 3D constructs (e.g., the 3D constructs tiles include fewer vertices) because the 3D will be rendered from a far distance. Any additional detail included in higher resolution 3D map tiles is not noticeable at such far distances.
  • Constructs and/or geometries of non-immersive and immersive viewing modes of some embodiments are separately defined in different sets of 3D map tiles. The different sets of 3D map tiles are generated by a map service provider based on 3D maps that the map service provider generates or imports from a 3D map data provider(s). The different 3D map tiles are used by the mapping application of some embodiments to render 3D map views for the different viewing modes of the 3D map. In some instances, the map service provider generates multiple sets of 3D map tiles for the same viewing mode. For instance, in some embodiments, the map service provider generates a set of 3D building tiles and a set of 3D road tiles for a non-immersive viewing mode. For an immersive viewing mode, the mapping service provider of some embodiments generates a set of 3D building tiles (and/or the same set of 3D building tiles for the non-immersive viewing mode) and a set of 3D navigation tiles.
  • FIG. 91 conceptually illustrates an example of a mapping application 9100 that renders 3D map views for different zoom levels of different viewing modes. As shown in this example, the non-immersive viewing mode is defined for viewing a 3D map at zoom levels 1 to N−1 while the immersive viewing mode is defined for viewing the 3D map at zoom levels N to N+M. In some embodiments, the application 9100 implements a portion or all of the mapping application described above and below by reference to FIGS. 1-108. As shown, FIG. 91 includes the mapping application 9100, a map service provider 9110, sets of 3D map tiles 9120, and sets of 3D map views 9130.
  • As mentioned above, a map service provider (e.g., a map server) generates and provides in some embodiments different sets of 3D map tiles of a 3D map for different zoom levels. As illustrated, the map service provider 9110 generates and provides a set of 3D map tiles 9120 for each of the zoom levels 1-N. In some embodiments, the map service provider 9110 is implemented by the map service described below in more detail by reference to FIG. 108. The mapping application 9100 generates 3D map views 9130 based on 3D map tiles received from the map service provider 9110.
  • The mapping application 9100 of some embodiments generates 3D map views at a particular zoom level based on 3D map tiles defined for the particular zoom level. For instance, as shown in FIG. 91, the mapping application 9100 uses the set of 3D map tiles 9120 defined for zoom level 1 to generate for the non-immersive viewing mode the set of 3D map views 9130 at zoom level 1. Similarly, the mapping application 9100 generates for the non-immersive and immersive viewing modes a set of 3D map views 9130 at other zoom levels from the set of 3D map tiles 9130 defined for the corresponding zoom level.
  • In some embodiments, the mapping application 9100 generates 3D map views for several zoom levels based on 3D map tiles defined for a single zoom level. As shown in this example, the mapping application 9100 uses the set of 3D map tiles 9120 defined for zoom level N to generate for the immersive viewing mode sets of 3D map tiles 9120 at zoom levels N to N+M. The mapping application 9100 of some embodiments generates 3D map views at N+1 to N+M zoom levels by modifying (e.g., scaling up and/or down) the data of the 3D map tiles (e.g., 3D constructs) defined for zoom level N.
  • As illustrated in FIG. 91, the mapping application 9100 generates 3D map views for a non-immersive viewing mode at a particular zoom level based on 3D map tiles defined for the particular zoom level whereas the mapping application 9100 generates 3D map views for an immersive viewing mode at a particular zoom level based on 3D map tiles defined for the particular zoom level. While FIG. 91 illustrates a mapping application that generates for an immersive viewing mode 3D map views at multiple different zoom levels based on a set of 3D map tiles for a particular zoom level, in some embodiments, the mapping application generates additional zoom levels for a non-immersive viewing mode.
  • In addition, FIG. 91 shows sets of 3D map tiles 9120 stored on a single storage of the map service provider 9110. In some embodiments, different sets of 3D map tiles 9120 are stored in different storages. For example, some 3D map tiles 9120 for the non-immersive viewing mode (some 3D map tiles 9120 from each of the zoom levels 1 to N−1 in this example) may be stored in a first storage (e.g., a 3D road tile storage) and some 3D map tiles 9120 for the immersive viewing mode (e.g., some 3D map tiles 9120 from zoom level N) are stored in a second storage (e.g., a 3D navigation tile storage). In some embodiments, some 3D map tiles (e.g., some 3D map tiles from each of the zoom levels 1 to N) are stored in yet another storage (e.g., a 3D building tile storage).
  • FIG. 92 illustrates the movement of the virtual camera 9200 around the region of a 3D map 9235 at three different stages 9205-9215. In particular, the 3D map 9235 is an example 3D map defined to be viewed by an immersive viewing mode of some embodiments. As noted above, in some embodiments, the map service provider from which the mapping application retrieves tiles only provides one set of 3D map tiles of the 3D map 9235 at a particular zoom level (e.g., zoom level 15). To render higher level zoom levels (e.g., zoom levels 16-21) based on these 3D map tiles, the mapping application of some such embodiments renders 3D map views at different zoom levels by modifying (e.g., scaling up and/or down) the data in the 3D map tiles (e.g., vertices, polygons, etc.). As shown, the region of the 3D map 9235 includes two building and a road that abuts another road.
  • The first stage 9205 illustrates the virtual camera 9200 at a particular location and position in the 3D map 9235. In some embodiments, the point at which the virtual camera 9200 is focusing (i.e., the point at which a line projecting out of the front of the virtual camera intersects the road) in the 3D map 9235 is referred to as a point of focus. In the first stage 9205, the virtual camera 9200's point of focus is near the intersection formed by the two roads. An example rendered image of the 3D map 9235 from the virtual camera 9200's point of view at this stage 9205 is illustrated in the 3D map view 9220. As shown, the 3D map view 9220 of the 3D map 9235 includes detailed constructs like trees, lane markers, asphalt (represented by a graying of the roads in this example).
  • The second stage 9210 shows the virtual camera 9200 at a different location and position in the 3D map 9235. As shown in the second stage 9210, the mapping application has moved the virtual camera 9200 down and towards the left of the 3D map 9235. For this example, the mapping application has moved the virtual camera 9200 in response to input (e.g., a gestural input such as pinch gesture or a double tap gesture) for zooming in on the 3D map 9235. From the first stage 9205 to the second stage 9210, the mapping application automatically moved the virtual camera 9200 in the manner described in order to zoom in on the 3D map 9235. An example rendered image of the 3D map 9235 from the virtual camera 9200's point of view at the second stage 9210 is illustrated in the 3D map view 9225. The 3D map view 9225 shows the buildings and trees larger and taller and the roads and lane markers are wider than that shown in the first stage 9205.
  • The third stage 9215 illustrates the virtual camera 9200 at another different location and position of the 3D map 9235. At this stage 9215, the mapping application has moved the virtual camera 9200 farther down and towards the left of the 3D map 9235 from the position of the virtual camera 9200 shown in the second stage 9210. Continuing with the example above, the mapping application has moved the virtual camera 9200 in response to input (e.g., a gestural input such as pinch gesture or a double tap gesture) for zooming in on the 3D map 9235. Between the second stage 9210 to the third stage 9215, the mapping application automatically moved the virtual camera 9200 in the manner described in order to zoom in on the 3D map 9235. An example rendered image of the 3D map 9235 from the virtual camera 9200's point of view at this stage 9215 is illustrated in the 3D map view 9230. As shown in the 3D map view 9230, the buildings and trees are larger and taller and the roads and lane markers are wider than that shown in the second stage 9210.
  • FIG. 93 illustrates the movement of the virtual camera 9300 around the region of a 3D map 9335 and a 3D map 9340 at three different stages 9305-9315. Specifically, the 3D map 9335 is similar to the 3D map 9235 described above by reference to FIG. 92. The 3D map 9340 in this example is a 3D map of the same geographical region as the 3D map 9335, but is defined to be viewed by a non-immersive viewing mode of some embodiments. As such, the region of the 3D map 9340 similarly includes two building and a road that abuts another road.
  • The first stage 9305 illustrates the virtual camera 9300 at a particular location and position in the 3D map 9335. In some embodiments, the point at which the virtual camera 9300 is focusing (i.e., the point at which a line projecting out of the front of the virtual camera intersects the road) in the 3D map 9335 is referred to as a point of focus. In the first stage 9305, the virtual camera 9300's point of focus is near the intersection formed by the two roads. An example rendered image of the 3D map 9335 from the virtual camera 9300's point of view at this stage 9305 is illustrated in the 3D map view 9320. As shown, the 3D map view 9320 of the 3D map 9335 includes detailed constructs like trees, lane markers, asphalt (represented by a graying of the roads in this example).
  • The second stage 9310 shows the virtual camera 9300 at a different location and position in the 3D map 9335. As shown in the second stage 9310, the mapping application has moved the virtual camera 9300 up and towards the right of the 3D map 9335. For this example, the mapping application has moved the virtual camera 9300 in response to input (e.g., a gestural input such as spread gesture or a two-touch tap gesture) for zooming out from the 3D map 9335. From the first stage 9305 to the second stage 9310, the mapping application automatically moved the virtual camera 9300 in the manner described in order to zoom out from the 3D map 9335. An example rendered image of the 3D map 9335 from the virtual camera 9300's point of view at the second stage 9310 is illustrated in the 3D map view 9325. The 3D map view 9325 shows the buildings and trees smaller and shorter and the roads and lane markers are narrower than that shown in the first stage 9305.
  • The third stage 9315 illustrates the virtual camera 9300 at another different location and position of the 3D map 9235. At this stage 9215, the mapping application has switched from the immersive viewing mode to the non-immersive viewing mode. In some embodiments, a particular zoom level is defined as the transition point between the immersive viewing mode and the non-immersive viewing mode. For instance, the mapping application of some embodiments uses the immersive viewing mode for viewing the region of the 3D map at zoom levels 15-21 and uses the non-immersive viewing mode for viewing the region of the 3D map at zoom levels 0-14. Thus, when the mapping application receives input to zoom from zoom level 15 to zoom level 14, the mapping application automatically switches from the immersive viewing mode to the non-immersive viewing mode. Similarly, when the mapping application receives input to zoom from zoom level 14 to zoom level 15, the mapping application automatically switches from the non-immersive viewing mode to the immersive viewing mode. Different embodiments may define the zoom level at which to switch between the two zoom levels differently.
  • In addition, some embodiments do not switch between immersive and non-immersive viewing modes based on the zoom level. For instance, different embodiments use the immersive viewing mode for turn-by-turn navigation and the non-immersive viewing mode for map browsing, or include a UI control that allows the user to switch between a non-immersive viewing mode and an immersive viewing mode.
  • FIG. 94 conceptually illustrates an example of a mapping application 9400 that renders 3D map views for different zoom levels of different viewing modes. As shown in this example, the non-immersive viewing mode is defined for viewing a 3D map at zoom levels 1 to X, while the immersive viewing mode is defined for viewing the 3D map at zoom levels X-K to X. Thus, the application may display a map at zoom levels X-K to X in either immersive or non-immersive mode. As shown, FIG. 94 includes the mapping application 9400 and map service provider 9410, the functionality of which is similar to that described above by reference to FIG. 91 (i.e., the map service provider 9410 generates and provides map tiles 9420, and the mapping application renders map views 9430 by using these tiles).
  • In this case, as in FIG. 91, the map service provider 9410 generates and provides a different set of 3D map tiles 9420 for each non-immersive zoom level, while only generating and providing a single set of 3D map tiles 9420 for the immersive viewing mode. The mapping application 9400 generates the map views for zoom levels X-K to X using the zoom level X-K map tiles. In some embodiments, the mapping application generates map views using the non-immersive 3D map tiles when in map browsing, route display, route inspection, and auto-stepping modes, and generates map views using the immersive 3D map tiles when in turn-by-turn navigation mode. These modes are described in greater detail by reference to FIGS. 105A-105B below.
  • In the above example of FIG. 93, the mapping application receives input to zoom out from a zoom level defined for the immersive viewing mode to another zoom level defined for the non-immersive viewing mode. As such, the mapping application performed a preload operation to prepare rendering 3D map views of the 3D map 9340, which is defined for the non-immersive viewing mode. Examples of a preloading operations is described below by reference to the FIGS. 97, 95, and 102.
  • After the preloading operation, the mapping application has moved the virtual camera 9300 from the position shown in the second stage 9310 to a relative position farther up and towards the right of the 3D map 9335. Continuing with the example above, the mapping application has moved the virtual camera 9300 in response to input (e.g., a gestural input such as pinch gesture or a double tap gesture) for zooming in on the 3D map 9335. Between the second stage 9310 to the third stage 9315, the mapping application automatically preloaded the 3D map 9340 and moved the virtual camera 9300 in the manner described in order to zoom out from on the 3D map 9335. An example rendered image of the 3D map 9335 from the virtual camera 9300's point of view at this stage 9315 is illustrated in the 3D map view 9330. As shown, the 3D map view 9330 contains the same buildings and roads, but does not contain any of the constructs and/or details shown in the 3D map views 9320 and 9325 since the mapping application is now rendering 3D map views from the 3D map 9340, which is for the less detailed non-immersive viewing mode.
  • As shown in FIGS. 92 and 93, the immersive viewing mode and the non-immersive viewing mode provide different levels of detail of a region of a 3D map based on the zoom level at which the region is viewed. In some embodiments, the mapping application renders different textures for buildings at different zoom levels. For instance, the mapping application of some embodiments renders more detailed textures (e.g., colors, patterns, etc.) for buildings in the immersive viewing mode and renders simpler textures (e.g., solid colors, etc.) for the same buildings in the non-immersive viewing mode. In some embodiments, the mapping application renders different textures for the same buildings at different zoom levels in the immersive viewing mode. Additionally, or conjunctively with rendering different textures for buildings based on different zoom levels, the mapping application of some embodiments renders different textures for buildings based on other factors (e.g., time of day, geographical region, season of the year, holidays, etc.) as well.
  • FIG. 95 conceptually illustrates a processing pipeline 9500 of the mapping application of some embodiments for rendering 3D map views 9560 based on different 3D map tiles 9540-9550. As shown, the processing pipeline 9500 includes a map rendering engine 9510, a virtual camera module 9520, a mesh builder 9530, a tile processor 9570, three different storages 9540-9550 of 3D map tiles, and a stylesheet storage 9555. In some embodiments, the navigation tiles storage 9540 stores 3D map tiles (also referred to as navigation tiles) for the immersive viewing mode, and the road tiles (also referred to as road tiles) storage 9545 store 3D map tiles for the non-immersive viewing mode. The building tiles storage 9550 of some embodiments stores 3D map tiles (also referring to as building tiles) for use in both immersive and non-immersive viewing modes. The stylesheets storage 9555 stores definitions for rendering textures for 3D map views 9560 and other styling information for rendering the 3D map views 9560.
  • The virtual camera 9520 identifies a location and orientation (e.g., perspective position, zoom level, etc.) from which to view a 3D map. The virtual camera 9520 sends the field of view of the 3D map (also referred to as a viewing frustum) to the tile processor 9570 for processing.
  • The tile processor 9570 receives field of views of 3D maps from the virtual camera 9520. In some embodiments, the tile processor 9570 performs any necessary culling (e.g., removing surface area too far away, removing objects that will be entirely behind other objects, etc.) to the 3D map view before sending the mesh builder 9530 “empty” virtual 3D map tiles, in some embodiments. The tile processor 9570 of some embodiments receives “built” virtual 3D map tiles from the mesh builder 9530 and sends them to the map rendering engine 9510 for rendering. In some embodiments, the tile processor 9570 is implemented by the controller and tile provider(s) described below by reference to FIGS. 98 and 102.
  • In some embodiments, the mesh builder 9530 prepares virtual 3D map tiles for tile processor 9570. The mesh builder 9530 requests 3D map tiles (e.g., decompressed 3D map tiles) from the 3D map tile storages 9540-9550 based on the viewing mode that is to be rendered for field of view of the 3D map. For instance, when the viewing mode is an immersive viewing mode, the mesh builder 9530 of some embodiments requests navigation map tiles from the storage 9540 and building tiles from the storage 9550. In some embodiments, the mesh builder 9530 requests road tiles from the storage 9545 and building tiles from the storage 9550.
  • Once the mesh builder 9530 receives the map tiles, the mesh builder 9530 builds a polygon mesh using vector data stored in the tiles. The mesh builder 9530 also provides texture information based on the styling information retrieved from the stylesheet storage 9555. In some embodiments, the mesh builder 9530 builds the polygon mesh on a tile-by-tile basis and sends the virtual 3D map tiles, which, in some embodiments, are a polygon mesh version of the virtual 3D map tiles received the mesh builder 9530 received from by the tile processor 9570.
  • The map rendering engine 9510 is responsible for generating a drawing (e.g., a 3D map view of a 3D map) to output to a display device based on the field of view received from the virtual camera 9520. Additional details of the mesh builder 9530, the virtual camera 9520, the tile processor 9570, and the map rendering engine 9510 are described below in further detail by reference to FIGS. 98 and 102.
  • An example operation of the processing pipeline 9500 will now be described. The virtual camera 9520 identifies a location and orientation from which the virtual camera 9520 views a 3D map. The virtual camera 9520 sends to the tile processor 9570 a field of view of the 3D map based on the identified location and orientation.
  • When the tile processor 9570 receives the field of view, the tile processor 9570 of some embodiments culls the field of view. The tile processor 9570 then sends virtual map tiles to the mesh builder 9530 for processing.
  • When the mapping application generates 3D map views in an immersive viewing mode, the mesh builder 9530 retrieves navigation tiles from the navigation tiles storage 9540 and building tiles from the building tiles storage 9550. However, when the mapping application generates 3D map views in a non-immersive viewing mode, the mesh builder 9530 instead retrieves road tiles from the road tiles storage 9545 and building tiles from the building tiles storage 9550. That is, different sets of 3D map tiles are used by the processing pipeline 9500 for rendering 3D map views in these different viewing modes.
  • In some embodiments, 3D map tiles are cached for a period of time in the storage 9540. Thus, in some such embodiments, if 3D map tiles are not available in the storage 9540, the desired 3D map tiles are retrieved from a map service.
  • Once the mesh builder 9530 has all the appropriate 3D map tiles, the mesh builder 9530 builds a polygon mesh based on vector data in the 3D map tiles. The mesh builder 9530 then sends virtual map tile versions of the 3D map tiles to the tile processor 9570.
  • When the tile processor 9570 receives the virtual map tiles from the mesh builder 9530, the tile processor 9570 sends them to the map rendering engine 9510 for rendering. The map rendering engine 9510 receives the virtual map tiles from the tile processor 9570 and renders a 3D map view 9560 based on the virtual map tiles.
  • The description of several figures above and below (e.g., FIGS. 95, 98, and 102) discusses processing pipelines for rendering 3D map views of a 3D map. In some embodiments, the processing pipeline generates and stores a data structure for rendering a map view. FIG. 96 conceptually illustrates a data structure 9600 used by the processing pipeline of some embodiments.
  • As shown, the data structure 9600 includes a virtual camera ID 9605, virtual camera location data 9610, viewing mode 9615, 3D map tiles 9620, stylesheet data 9625, 3D map tile cache 9630, virtual map tiles 9635, a 3D map view 9640, and other data 9645.
  • The virtual camera ID 9605 is a unique identifier for identifying a virtual camera that is used to render a 3D map view. As mentioned above and below, the processing pipeline of some embodiments instantiates several virtual cameras for identifying views of the 3D map. As shown in FIG. 96, a set of virtual cameras 9650 are available for the processing pipeline to use. In this example, the virtual camera ID 9605 is identifying the virtual camera 2 for the processing pipeline to use to render the 3D map view.
  • The virtual camera location data 9610 stores information about the location of the virtual camera identified by the virtual camera ID 9605. Examples of such information include coordinates of the virtual camera (e.g., x, y, and z coordinates), a pan angle of the virtual camera, a tilt angle of the virtual camera, a roll angle of the virtual camera, a zoom level of the virtual camera, etc.
  • The viewing mode 9615 is data that indicates the viewing mode in which to render the 3D map view. For instance, the viewing mode 9615 might store data that indicates a non-immersive viewing mode, an immersive viewing mode, a satellite viewing mode, a hybrid viewing mode, etc.
  • The 3D map tiles 9620 is the set of 3D map tiles that represent the portion of the 3D map from which the 3D map is to be rendered. The processing pipeline of some embodiments uses the virtual camera location data 9610 and the viewing mode 9615 to identify the portion and retrieve the corresponding 3D map tiles.
  • The stylesheet data 9625 contains styling information that the processing pipeline uses to build meshes. In some embodiments, the processing pipeline uses the stylesheet data 9625 to determine texture data, shadow data, triangulation data, etc.
  • The 3D map tile cache 9630 is used to cache 3D map tiles. In some embodiments, the processing pipeline caches recently used 3D map tiles, often used 3D map tiles, 3D map tiles that the processing pipeline determines is likely to be used in the near future, etc.
  • The virtual map tiles 9635 stores map tiles that include built map constructs. As shown, a virtual map tile includes building constructs, road/navigation constructs, label constructs, landcover constructs, along with other constructs. In particular, the virtual map tiles 9635 of some embodiments stores map tiles that include road constructs when the 3D map view is to be rendered in the non-immersive viewing mode and stores map tiles that include navigation constructs when the 3D map view is to be rendered in the immersive viewing mode.
  • The 3D map view 9640 contains the 3D map view that the processing pipeline renders based on the various information in the data structure 9600 that the mapping application of some embodiments displays. Other data 9645 stores information that the processing pipeline in some embodiments might need to render the 3D map view (e.g., the number of mesh builders to use, the number of tile providers to use, etc.).
  • One of ordinary skill in the art will recognize that the data structure 9600 is just one possible data structure that the processing pipeline of some embodiments uses to store the required information to render a 3D map view. For example, different embodiments might store additional or less information, store the information in a different order, use a different structure to store the data, etc.
  • FIG. 97 conceptually illustrates a state diagram 9700 of a mapping application of some embodiments. As shown, the state diagram 9700 includes states 9710-9770 of the mapping application when the mapping application switches between a first viewing mode and a second view mode during a route navigation. In some embodiments, the first and second viewing modes are a non-immersive viewing mode and an immersive viewing mode. The first and second viewing modes of some embodiments are for viewing different 3D maps of the same geographical region. That is, a first 3D map that is viewed using the first viewing mode and a second 3D map that is viewed using the second viewing mode are both for viewing the same geographic region.
  • At state 9710, the mapping application renders 3D map views in a first map viewing mode. In some embodiments, the mapping application enters state 9710 when the mapping application enters a navigation mode (e.g., by selecting UI item for initiating a route navigation). For this example, when the mapping application enters state 9710, the mapping application uses a first virtual camera to view a first 3D map and renders 3D map views for the map viewing mode in a non-immersive viewing mode.
  • In state 9710, the mapping application of some embodiments receives various commands (e.g., zoom commands, pan commands, rotate commands, tilt commands, etc.) to move the virtual camera around the first 3D map and render 3D map views based on the position of the virtual camera in the first 3D map. As the virtual camera moves around the first 3D map, the mapping application retrieves tiles from a map service when the virtual camera to a region of the first 3D map about which the mapping application does not have data.
  • At state 9710, if the mapping application determines that a transition to a second viewing mode is likely, the mapping application transitions to state 9720 to perform a preloading operation for the second viewing mode in order to provide a smooth transition from the first viewing mode to the second viewing mode (e.g., to prevent any stuttering or delays when transitioning between modes). In this example, the second viewing mode is the immersive viewing mode. The mapping application of some embodiments determines to transition to the second view mode is likely based on any number of different factors. One example of such a factor includes a zoom level at which the virtual camera is viewing the first 3D map. For example, if the identified zoom level of the map view is a zoom level in which roads are displayed as yellow lines (e.g., a non-immersive, or standard viewing mode), and the zoom level is within a threshold amount of zoom levels from a zoom level defined for transitioning between the non-immersive mode and an immersive mode, the mapping application determines that a transition to second viewing mode is likely. Additional and/or other factors that the mapping application considers include a set of heuristics that indicate that a transition to the second viewing mode is likely.
  • At state 9720, the mapping application downloads data for a second loader that the mapping application generates for the second viewing mode. In some embodiments, the data includes 3D map tiles and styling information (e.g., stylesheets.) required for the second viewing mode (e.g., 3D map tiles that include areas around the user's location and along the route navigation). The loader loads data related to the second 3D map. In addition, the mapping application generates a second virtual camera for viewing the second 3D map and generating 3D map views of the second 3D map. After generating the second virtual camera and loader and downloading the data, the mapping application transitions to state 9730.
  • When the mapping application transitions to state 9730, the mapping application decodes the 3D map tiles for second 3D map. In some embodiments, decoding the data also includes creating meshes for geometries in the second 3D map, retrieving the styling information, associating the styling information with the generated meshes, and determining the draw order of meshes. The mapping application performs additional and/or other operations in some embodiments when decoding the downloaded data. Once the mapping application decodes the data, the mapping application transitions to state 9740.
  • At state 9740, the mapping application prepares the rendering engine to render 3D map views of the second 3D map using the second virtual camera. To prepare the rendering engine, the mapping application of some embodiments generates texture preprocessors, precompiles the rendering shaders, builds styling information for nearby geometry, generates style resources, generates textures based on the styling information, and creates any resources needed for the geometry. For instance, if there's a park near the user's location, the process 9700 determines styling information related to the park and then generates any and all resources necessary to style the park. After preparing the rendering engine, the mapping application transitions to state 9750.
  • In state 9750, the mapping application continues to render 3D map views of the first 3D map using the first virtual camera. Here, the mapping application also determines whether to begin transitioning from the first viewing mode to the second viewing mode. If the mapping application determines that a transition from the first viewing mode to the second viewing mode is unlikely to be needed (e.g., after a defined amount of time has elapsed, the zoom level of the first viewing mode has changed a threshold amount to indicate that a transition is not likely or will not occur, etc.), the mapping application transitions to state 9710. If the mapping application determines to transition from the first viewing mode to the second viewing mode (e.g., the mapping application enters a zoom level that requires the second viewing mode, the application enters navigation mode, etc.), the mapping application transitions to state 9760.
  • When the mapping application transitions to state 9760, the mapping application performs the blending operation by performing a cross blend of the 3D map views of the first 3D map rendered using the first virtual camera with the 3D map views of the second 3D map rendered using the second virtual camera. In some embodiments, the mapping application renders the 3D map views of the first 3D map first and then renders the 3D map views of the second 3D map. The mapping application of some embodiments repeatedly alternates between rendering a 3D map view of the first 3D map and rendering a 3D map view of the second 3D map for the blending operation. Once the blending operation is complete, the mapping application transitions to state 9770.
  • At state 9770, the mapping application sets the second viewing mode as the first viewing mode and then transitions back to state 9710. Since the mapping application can switch between the first and second viewing modes any number of times, the mapping application returns to state 9710 in order to preload the second viewing mode to continue providing seamless transitions between the two viewing modes.
  • C. Image Processing Pipeline
  • FIG. 98 conceptually illustrates a processing pipeline 9800 performed by the mapping application of some embodiments in order to render a map for display at the client device (e.g., on the display of the client device). As illustrated, the processing pipeline 9800 includes a requestor 9805, a loader/decompressor 9810, a tile processor 9850, a set of mesh builders 9815, a tile provider 9820, a virtual camera 9880, and a map rendering engine 9825.
  • The tile processor 9850 of some embodiments receives requests for map tiles from the mesh builders 9815 and performs a multiplexing operation before forwarding the requests. The mesh builders 9815, as will be described below, identify existing map tiles (that are stored on a mapping service server or in a cache on the device performing the processing pipeline 9800) needed to build their respective meshes. In some embodiments, the map tiles are referenced as nodes of a quadtree. The tile processor acts as a multiplexer when multiple mesh builders request the same tile. As the mesh builders request tiles, in some embodiments the tile processor 9850 stores these tiles in its queue. After either a particular period of time or after a particular number of tiles have been requested, the tile processor 9850 flushes the queue and sends the tile list to the loader/decompressor 9810.
  • The loader/decompressor 9810 receives the multiplexed tile list 9835 from the tile processor 9850 and handles the return of decompressed tiles 9845 to the tile processor 9850. In some embodiments, the loader/decompressor 9810 first checks one or more caches to determine whether it has the requested tiles stored at the device on which the mapping application operates. As shown, some embodiments include both a first tile cache 9853 stored on non-volatile memory (e.g., disk, flash memory, etc.) as well as a second tile cache 9854 stored in volatile memory (e.g., random access memory). When the loader/decompressor 9810 finds the tiles in one of the caches 9853 and 9854, it sends these tiles back to the tile processor 9850 (for return to the requesting mesh builder(s) 9815).
  • When the loader/decompressor 9810 does not have the tiles in its cache, it sends a request to the requestor 9805 for the remaining tiles. Upon receiving these map tiles 9840 in a compressed format, the loader/decompressor decompresses the received tiles to generate decompressed tiles 9845. In some embodiments, after generating the map tiles as described above, the mapping service also compresses the tiles using an encoding technique. Different embodiments use different encoding techniques. The loader/decompressor 9810 returns these decompressed tiles 9845 to the tile processor 9850, and in some cases also stores them in one or both of the tile caches 9853 and 9854.
  • The requestor 9805, in some embodiments, receives requests for map tiles from the loader/decompressor 9810 (which in turn receives the requests from the tile processor 9850). These map tiles, in some embodiments, are stored on a server (e.g., a server of the mapping service to which the user's device connects). The requestor sends a tile list 9836 (received from the loader/decompressor 9810) that identifies the tiles needed from the mapping service (and not available in the tile caches 9853 and 9854. In some embodiments, the requestor takes advantage of the operating device's network connections (e.g., a Wi-Fi connection, a GSM connection, etc.) to contact the mapping service through the Internet to retrieve the needed map tiles. Upon receiving the tiles (in a compressed form) from the mapping service, the requestor 9805 returns the compressed tiles 9840 to the loader/decompressor.
  • In some embodiments, the requestor 9805 (or the tile processor 9850, or a different portion of the pipeline) identifies tiles at additional zoom levels that cover the same geographical area as the initially requested tiles, and adds these tiles to the request list 9836 so that the tiles will be available if needed in the near future. In addition, some embodiments automatically request tiles at the same (or different zoom levels) for nearby geographical regions, in order to have the tiles available in case the user pans the map. In some embodiments, the requestor 9805, loader/decompressor 9810, and tile processor 9850 function as an independent portion of the processing pipeline, with the mesh builders 9815 as the “clients” of this section.
  • The mesh builders 9815 (also referred to as tile sources) of some embodiments are instantiated by the tile provider 9820 in order to build different layers of virtual map tiles. Depending on the type of map being displayed by the mapping application, the tile provider 9820 may instantiate a different number and different types of mesh builders 9815. For instance, for a flyover (or satellite) view map, the tile provider 9820 might only instantiate one mesh builder 9815, as the flyover map tiles of some embodiments do not contain multiple layers of data. In fact, in some embodiments, the flyover map tiles contain an already-built mesh generated at the mapping service for which the flyover images (taken by a satellite, airplane, helicopter, etc.) are used as textures. However, in some embodiments, additional mesh builders may be instantiated for generating the labels to overlay on the flyover images when the application is in a hybrid mode. The generation of flyover maps of some embodiments are described in PCT Application PCT/EP2011/054155, entitled “3D Streets.” PCT Application PCT/EP2011/054155 is incorporated herein by reference. For a 2D or 3D rendered vector map (i.e., a non-satellite image map), some embodiments instantiate separate mesh builders 9815 to build meshes for landcover polygon data (e.g., parks, bodies of water, etc.), roads, place of interest markers, point labels (e.g., labels for parks, etc.), road labels (e.g., road labels in map browsing mode and road signs in navigation mode), traffic (if displaying traffic), buildings, raster data (for certain objects at certain zoom levels), as well as other layers of data to incorporate into the map.
  • The mesh builders 9815 of some embodiments, receive “empty” virtual map tiles 9860 from the tile provider 9820 and return “built” virtual map tiles 9865 to the tile provider 9820. That is, the tile provider 9820 sends to each of the mesh builders 9815 one or more virtual map tiles 9860. Each of the virtual map tiles 9860 indicates an area of the world for which to draw a mesh. Upon receiving such a virtual map tile 9860, a mesh builder 9815 identifies the map tiles needed from the mapping service, and sends its list to the tile processor 9850.
  • Upon receiving the tiles back from tile processor 9850, the mesh builder uses vector data stored in the tiles to build a polygon mesh for the area described by the virtual map tile. In some embodiments, the mesh builder 9815 uses several different functions to build the mesh. These functions include the mesh generator 9816, the triangulator 9817, the shadow generator 9818, and the texture decoder 9819. In some embodiments, these functions (and additional mesh building functions) are available to each mesh builder, with different mesh builders 9815 using different functions. For instance, the mesh builder responsible for the buildings layer may use a mesh generator 9816 and a triangulator 9817. In addition, several different types of shadow generators may be available to the mesh builder 9815, including a first shadow generator for creating dynamic shadows (that change as the map rotates) and a second shadow generator for creating a raster image drop shadow.
  • The mesh generator 9816 generates a mesh of vertices using the tile vector data, in some embodiments. The triangulator 9817 generates triangles from the mesh, to simplify the eventual rendering. The shadow generator 9818 adds shadows to the mesh (e.g., by labeling vertices and/or polygons with values indicating to the renderer to draw a shadow, or how dark of a shadow to draw. The texture decoder 9819 decodes texture information (e.g., from a stylesheet) and applies the texture information to the mesh. In different embodiments, the texture information may indicate colors, patterns, etc. to add to the polygons when rendered, which is encoded into the mesh. After building its mesh, each mesh builder 9815 returns its virtual map tiles 9865 to the tile provider 9820 with its layer of the mesh filled in.
  • In some embodiments, the texture information may be determined based on stylesheet data 9855. Furthermore, some embodiments also use this stylesheet data 9855 to determine the shadow, triangulation, and or mesh construction data. Using stylesheet-driven rendering enables simple modification to many aspects of the map output, because changes to a texture, color, etc. can be made through a minor modification of a stylesheet. As a result, textures can be dynamically created on the fly. An example benefit of the stylesheet-driven rendering is the facilitation of using different textures for certain types of objects at different zoom levels or geographic regions. For instance, when viewed at a low zoom level (less detail), some embodiments might color a park a simple light green. On the other hand, as the user zooms in to a higher zoom level (more detail), the stylesheets indicate to apply a pattern (e.g., a foliage pattern) to the park region. Similarly, patterns at higher zoom levels could be added to buildings, bodies of water, asphalt, urban land cover, etc. This information can be coded into a stylesheet and then the mesh builder simply adds the appropriate texture information to a tile mesh based on the zoom level of the tile.
  • By tagging roads (e.g., as urban, suburban, or rural), the mapping service can induce the client application to use different textures for the land cover regions around those roads. In addition, land cover region tags can be updated by the server based on metrics indicative of the sort of area covered by the land cover region. For instance, some embodiments (on the mapping service end) determine the density of mobile devices within the region (e.g., based on the number of devices accessing the mapping service) and generate tags for the land cover. The stylesheets stored by the client devices (which may be updated from the mapping service, in some embodiments) then indicate how to draw these land cover regions. Similarly, different styles can be used for rendering aspects of different regions (e.g., desert, forest, rocky, etc. for land cover; different colors for labels in different states; different colors, textures, and/or casing for different roads, or other such distinctions).
  • FIG. 99 illustrates the application of different textures to different types of roads for some embodiments. Specifically, this figure illustrates a map presentation 9900 in the mapping application of some embodiments that shows a freeway entrance ramp. In this case, the application identifies the road marked as a freeway and the road marked as an entrance ramp or slip road, and uses the stylesheet to provide different textures (in this case, asphalt shades) for the different types of roads.
  • Some embodiments denote roads as dominant or non-dominant, and render the roads differently accordingly. For instance, arterial roads might be considered dominant as compared to connector (e.g., residential) roads. FIG. 100 illustrates a map presentation 10000 that includes one arterial road and two connector roads. In this case, the arterial road is considered the dominant road, and therefore the application draws the arterial road larger and with a different, more prominent casing. In addition, in some embodiments the application colors the arterial road darker so that it stands out more prominently. In some embodiments, FIGS. 99 and 100 illustrate the rendering of roads using immersive navigation tiles, in which the roads are defined as 3D polygons. In some such embodiments, the navigation tiles indicate what road casing should be displayed through annotation of the road polygon vertices.
  • Map tiles of some embodiments (for non-immersive map browsing view, rather than immersive navigation view), on the other hand, store the road data as vectors (i.e., one-dimensional constructs). The mapping application nevertheless renders some of the roads differently, including rendering dominant roads (e.g., arterial roads) differently from non-dominant roads. FIG. 101 illustrates a non-immersive map presentation 10100 illustrating the rendering of roads in a map tile, in map browsing view. In this case, one of the roads is classified as dominant, and therefore the mesh built for the road is different from the other surrounding roads. The dominant road is displayed as darker and thicker than the other surrounding roads in some embodiments.
  • Some embodiments dynamically determine which roads within the map are dominant and display the dominant roads differently from non-dominant roads within the map (e.g., by coloring the roads differently, drawing the dominant roads thicker than the non-dominant roads, using different casing for the dominant roads, etc.). In order to determine which roads are dominant within a map, some embodiments use data provided about the type of roads to be drawn for the map. For example, roads may be classified as highways, arterial roads, and non-arterial roads, with sub-classifications in some embodiments. In general, arterial roads are larger roads and carry more traffic than non-arterial roads, and tend to have the right of way at intersections with non-arterial roads. Thus, when a map display has both arterial roads and non-arterial roads, some embodiments draw the arterial roads as dominant. On the other hand, when a map display has no arterial roads, the mapping application of some embodiments selects some of the non-arterial roads to be drawn as dominant roads. However, rather than only examining the actual portion of the map to display for arterial roads, some embodiments identify roads located within a region of a particular distance around the map as well. If arterial roads are present within that region, then the application does not draw any of the non-arterial roads as dominant, so as to avoid having to change the appearance of the road suddenly when the arterial road enters the map display.
  • The tile provider 9820 receives from the controller 9875 a particular view (i.e., a volume, or viewing frustum) that represents the map view to be displayed (i.e., the volume visible from the virtual camera 9880). The tile provider performs any culling (e.g., identifying the surface area to be displayed in the virtual map tile), then sends these virtual map tiles 9860 to the mesh builders 9815.
  • The tile provider 9820 then receives the built virtual map tiles 9865 from the mesh builders and, in some embodiments, performs culling on the built mesh using the particular view from the virtual camera 9880 (e.g., removing surface area too far away, removing objects that will be entirely behind other objects, etc.). In some embodiments, the tile provider 9820 receives the built virtual map tiles 9865 from the different mesh builders at different times (e.g., due to different processing times to complete more and less complicated meshes, different time elapsed before receiving the necessary map tiles from the tile processor 9850, etc.). Once all of the layers of virtual map tiles have been returned, the tile provider 9820 of some embodiments puts the layers together and releases the data to the controller 9875 for rendering.
  • In some embodiments, the tile provider 9820 may have already received a new virtual camera volume for which to build a mesh before the mesh builders have returned their data. For instance, when the user quickly pans or zooms a map, the data returned by the mesh builders may be out of date. In some embodiments, the tile provider either drops the built virtual map tile layers or stores them in memory. Whether to drop the built virtual map tiles depends, in different embodiments, on whether it is likely the built tiles will be needed soon (e.g., how much the user has moved the virtual camera, whether a navigation is running that makes it unlikely the application will display the older data) and the amount of memory currently in use.
  • The virtual camera 9880 generates a volume or surface for the pipeline 9800 to render, and sends this information to the controller 9875. Based on a particular location and orientation from which the map will be rendered (i.e., the point in 3D space from which the user “views” the map), the virtual camera identifies a field of view to actually send to the tile provider 9820. In some embodiments, when the mapping application is rendering the 3D perspective view for navigation, the field of view of the virtual camera is determined according to an algorithm that generates a new virtual camera location and orientation at regular intervals based on the movement of the user device.
  • The controller 9875 is responsible for managing the tile provider 9820, virtual camera 9880, and map rendering engine 9825 in some embodiments. In some embodiments, multiple tile providers may actually be instantiated, and the controller puts together several virtual map tiles (e.g., map tiles and building tiles) to create a scene that is handed off to the map rendering engine 9825.
  • The map rendering engine 9825 is responsible for generating a drawing to output to a display device based on the mesh tiles 9865 sent from the virtual camera. As shown, the map rendering engine 9825 of some embodiments has several sub-processes. In some embodiments, each different element is rendered by a different sub-process, with the rendering engine 9825 handling the occlusion of different layers of objects (e.g., placing labels above or behind different buildings, generating roads on top of land cover, etc. This figure illustrates a road rendering process 9826, a building rendering process 9827, and a label rendering process 9828. Examples of additional processes include a vegetation rendering process, a raster traffic rendering process, a raster road rendering process, a satellite rendering process, a polygon rendering process, a background raster rendering process, etc.
  • Each of the rendering processes includes a set of rendering parameters; illustrated are road parameters 9836, building parameters 9837, and label parameters 9838. In some embodiments, this data includes information on how to render the roads (e.g., shader information, textures to use for different types of roads, etc.).
  • In some embodiments, these sets of rendering parameters are generated at least in part by a rendering engine preparation operation 9870. The rendering engine preparation operation 9870 includes a shader compiler 9871 and a texture loader 9872, among other operations. The shader compiler 9871 compiles shaders that the rendering engine will use, and the texture loader 9872 loads texture information (e.g., into the rendering parameters). This texture information may come from the stylesheet data 9855 in some embodiments.
  • The operation of the rendering pipeline 9800 in some embodiments will now be described. Based on user input to view a particular map region at a particular zoom level, the virtual camera 9880 specifies a location and orientation from which to view the map region, and sends this viewing frustum, or volume, to the controller 9875. The controller 9875 instantiates one or more tile providers. While one tile provider 9820 is shown in this figure, some embodiments allow the instantiation of multiple tile providers at once (e.g., as shown below in FIG. 102). For instance, some embodiments instantiate separate tile providers for building tiles and for map tiles.
  • The tile provider 9820 performs any culling necessary to generate an empty virtual map tile identifying regions of the map region for which a mesh needs to be built, and sends the empty virtual map tiles 9860 to the mesh builders 9815, which are instantiated for the different layers of the drawn map (e.g., roads, land cover, POI labels, etc.). The mesh builders 9815 use a manifest received from the mapping service that identifies the different tiles available on the mapping service server (i.e., as nodes of a quadtree). The mesh builders 9815 request specific map tiles from the tile processor 9850, which removes any duplicate requests and sends a tile list 9835 to the loader/decompressor 9810.
  • The loader/decompressor 9810 determines whether the requested tiles are stored in the tile caches (either the non-volatile storage cache 9853 or the volatile storage cache 9854), and returns any such tiles to the tile processor 9850 for distribution to the requesting mesh builders 9815. For any tiles not already stored locally, the loader/decompressor 9810 sends a request to the requestor 9805, which sends tile list 9836 (a pared-down version of tile list 9835) to a remote mapping service server. The requestor 9805 receives from the mapping service, and forwards to the loader/decompressor 9810, the requested map tiles in compressed form 9840. The loader/decompressor 9810 decompresses (e.g., decodes) these tiles, stores them in its cache(s), and sends the decompressed tiles 9845 to the tile processor 9850 for return to the mesh builders 9815.
  • Once a particular mesh builder 9815 has received its map tiles, it begins using the vector data stored in the map tiles to build the mesh for the virtual map tiles sent from the tile provider 9820. After building the mesh for its map layer, the mesh builder 9815 sends the built virtual map tile 9865 back to the tile provider 9820. The tile provider 9820 waits until it has received all of the virtual map tiles from the various mesh builders 9815, then layers these together and sends the completed virtual map tile to the controller 9875. The controller stitches together the returned tiles from all of its tile providers (e.g., a virtual map tile and a virtual building tile) and sends this scene to the rendering engine 9825. The map rendering engine 9825 uses the information in the map tiles to draw the scene for display.
  • The above pipeline is illustrated for a single scene from a single