CN116416390A

CN116416390A - Three-dimensional map display method and device

Info

Publication number: CN116416390A
Application number: CN202111671610.0A
Authority: CN
Inventors: 张侃; 代蕊蕊
Original assignee: Tencent Technology Shenzhen Co Ltd
Current assignee: Tencent Technology Shenzhen Co Ltd
Priority date: 2021-12-31
Filing date: 2021-12-31
Publication date: 2023-07-11

Abstract

The application provides a three-dimensional map display method and device; the method is applied to the map field, and comprises the following steps: drawing a terrain background in a three-dimensional map based on three-dimensional coordinate data of grid vertices of a plurality of grids in the terrain background; according to three-dimensional coordinate data of grid vertices of a target grid, determining at least two candidate planes in the target grid, and determining the candidate plane where the surface element is located as a target plane, wherein the target grid is a grid where the surface element to be rendered is located in a plurality of grids; determining the elevation value of the bottom surface center point of the surface element based on the two-dimensional coordinates of the bottom surface center point of the surface element and the target plane; and drawing the surface element at a position which coincides with the bottom surface center point in the terrain background according to the elevation value of the bottom surface center point of the surface element. Through this application, can effectively improve the elevation value precision in the three-dimensional map to realize the accurate laminating of topography background and earth's surface element.

Description

Three-dimensional map display method and device

Technical Field

The present disclosure relates to the field of map technologies, and in particular, to a method and an apparatus for displaying a three-dimensional map.

Background

Along with the rapid development of the electronic map technology, the requirements of people on the display quality of various three-dimensional maps are higher and higher, the three-dimensional maps can show buildings in cities or mountain rivers in nature from the three-dimensional perspective, the expression forms are quite rich and visual, and the display of the three-dimensional maps can be applied to the fields of traffic, mapping, navigation, network games and the like.

In the related art, when the surface elements are displayed in the three-dimensional map, due to insufficient accuracy of the elevation values of the three-dimensional map, an elevation value sampling point is set in the three-dimensional map at a longer distance, so that a large number of display areas in the three-dimensional map lack accurate elevation values, and the surface elements in the three-dimensional map float or sink in the terrain background due to the lack of accurate elevation values.

The related technology has no effective solution for improving the accuracy of the elevation value in the three-dimensional map so as to realize the accurate fitting of the terrain background and the surface elements.

Disclosure of Invention

The embodiment of the application provides a three-dimensional map display method, a three-dimensional map display device, electronic equipment, a computer-readable storage medium and a computer program product, which can effectively improve the accuracy of elevation values in a three-dimensional map, thereby realizing the accurate attachment of a terrain background and surface elements.

The technical scheme of the embodiment of the application is realized as follows:

the embodiment of the application provides a three-dimensional map display method, which comprises the following steps:

drawing a terrain background in the three-dimensional map based on three-dimensional coordinate data of grid vertices of a plurality of grids in the terrain background;

determining at least two candidate planes in a target grid according to three-dimensional coordinate data of grid vertices of the target grid, and determining the candidate plane where the surface element is located as a target plane, wherein the target grid is a grid where the surface element to be rendered is located in the multiple grids;

determining an elevation value of a bottom surface center point of the surface element based on the two-dimensional coordinates of the bottom surface center point of the surface element and the target plane;

and drawing the surface element at a position which coincides with the bottom surface center point in the terrain background according to the elevation value of the bottom surface center point of the surface element.

The embodiment of the application provides a display device of a three-dimensional map, which comprises:

the first drawing module is used for drawing the terrain background in the three-dimensional map based on three-dimensional coordinate data of grid vertexes of a plurality of grids in the terrain background;

The first determining module is used for determining at least two candidate planes in the target grid according to three-dimensional coordinate data of grid vertices of the target grid, and determining the candidate plane where the surface element is located as a target plane, wherein the target grid is a grid where the surface element to be rendered is located in the multiple grids;

the second determining module is used for determining the elevation value of the bottom surface center point of the surface element based on the two-dimensional coordinates of the bottom surface center point of the surface element and the target plane;

and the second drawing module is used for drawing the surface element at a position which coincides with the bottom surface center point in the terrain background according to the elevation value of the bottom surface center point of the surface element.

An embodiment of the present application provides an electronic device, including:

a memory for storing executable instructions;

and the processor is used for realizing the three-dimensional map display method provided by the embodiment of the application when executing the executable instructions stored in the memory.

The embodiment of the application provides a computer readable storage medium, which stores executable instructions for realizing the three-dimensional map display method provided by the embodiment of the application when being executed by a processor.

Embodiments of the present application provide a computer program product or computer program comprising computer instructions stored in a computer readable storage medium. The processor of the electronic device reads the computer instructions from the computer readable storage medium, and the processor executes the computer instructions, so that the electronic device executes the three-dimensional map display method according to the embodiment of the application.

The embodiment of the application has the following beneficial effects:

the target plane where the surface element is located is determined through the target grid where the surface element is located in the terrain background, and then the elevation value of the bottom surface center point is determined based on the target plane, so that the elevation values of the bottom surface center points of different surface elements can be changed smoothly according to the two-dimensional coordinates, and when the surface element is drawn at the position where the elevation value of the bottom surface center point coincides with the bottom surface center point in the terrain background according to the elevation value of the bottom surface center point, the accurate attachment of the terrain background and the surface element can be realized.

Drawings

Fig. 1 is a schematic structural diagram of a display system architecture of a three-dimensional map according to an embodiment of the present disclosure;

fig. 2 is a schematic structural diagram of a display device for a three-dimensional map according to an embodiment of the present application;

Fig. 3A to 3D are schematic flow diagrams of a method for displaying a three-dimensional map according to an embodiment of the present application;

fig. 4A is a schematic diagram of a display method of a three-dimensional map in the related art;

fig. 4B is an effect schematic diagram of a display method of a three-dimensional map provided in an embodiment of the present application;

fig. 4C is a flowchart of a method for displaying a three-dimensional map according to an embodiment of the present application;

fig. 4D to fig. 4H are schematic diagrams of a three-dimensional map display method according to an embodiment of the present application;

fig. 4I is a flowchart illustrating a method for displaying a three-dimensional map according to an embodiment of the present application.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the present application more apparent, the present application will be described in further detail with reference to the accompanying drawings, and the described embodiments should not be construed as limiting the present application, and all other embodiments obtained by those skilled in the art without making any inventive effort are within the scope of the present application.

In the following description, reference is made to "some embodiments" which describe a subset of all possible embodiments, but it is to be understood that "some embodiments" can be the same subset or different subsets of all possible embodiments and can be combined with one another without conflict.

In the following description, the terms "first", "second", "third" and the like are merely used to distinguish similar objects and do not represent a specific ordering of the objects, it being understood that the "first", "second", "third" may be interchanged with a specific order or sequence, as permitted, to enable embodiments of the application described herein to be practiced otherwise than as illustrated or described herein.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of the present application only and is not intended to be limiting of the present application.

Before further describing embodiments of the present application in detail, the terms and expressions that are referred to in the embodiments of the present application are described, and are suitable for the following explanation.

1) Spatial plane equation: refers to an equation corresponding to all points in space that are in the same plane, and the general formula is ax+by+cz+d=0. Within the spatial coordinate system, the equations of the plane can be represented By the ternary once equation ax+by+cz+d=0, which is xyz. Since the point normal equation a (x-x 0) +b (y-y 0) +c (z-z 0) =0 for a plane is a one-time equation for x, y, x, and any plane can be determined by a point above it and its normal vector, any plane can be represented by a ternary one-time equation.

2) Normal vector: if a non-zero vector is perpendicular to a plane, this vector is called the normal vector of the plane, simply the normal vector. Any vector on a plane is perpendicular to the normal vector to that plane.

3) Digital elevation model (Digital Elevation Model, DEM): the method is realized by digital simulation of ground topography (namely digital expression of topography surface morphology) through limited topography elevation data, is a physical ground model for representing ground elevation in the form of a group of ordered value arrays, is a branch of a digital topography model (Digital Terrain Model, DTM), and is a spatial distribution describing linear and nonlinear combinations of various topography factors including elevation, such as factors of gradient, slope direction, gradient change rate and the like. There are various data organization expression forms of the digital elevation model, wherein two types of regular rectangular grids and irregular triangular grids are commonly used in land utilization engineering.

4) Regular rectangular grid: the regular rectangular grid is a data set of plane coordinates (z, y) of terrain points and equation (z) thereof which are arranged at equal intervals in the Z, Y axial direction on a Gaussian projection platform, and the plane coordinates of any point P_ { i, j } can be calculated according to the row and column numbers i, j of the point in the DEM and basic information stored in the DEM file. The rectangular grid DEM has the advantages of small storage capacity, capability of compressing and storing, and convenience in use and management. In the agricultural land development and finishing, the square grid method is generally adopted when the earthwork is measured and calculated due to the small range and small terrain variation, so that the DEM is more suitable to be formed by the rectangular grid method.

5) Irregular triangular net: the irregular triangular net is a DEM expressed by the irregular triangular net, and is commonly called DEM or TIN (Triangulated Irregular Network), and because each point forming the TIN is original data, interpolation precision loss is avoided, the TIN can well estimate characteristic points and lines of the landform, and the complex landform is expressed more accurately than the rectangular grid. But the data size of the TIN is large.

6) Three-dimensional map (Three Dimensional Map): a three-dimensional electronic map, or a 3D electronic map, is a three-dimensional, abstract description of one or more aspects of the real world or a portion thereof, to a certain extent, based on a three-dimensional electronic map database. The three-dimensional electronic map not only provides map searching functions such as map inquiry, travel navigation and the like for users through visual geographic live-action simulation expression modes, but also integrates a series of services such as living information, electronic commerce, virtual communities, travel navigation, game picture display and the like. The three-dimensional map includes a terrain background and surface elements.

7) Terrain background: the three-dimensional map is a set of geographic elements representing the topography and the topography, and is a component part representing the surface relief form, the geographic position and the shape in the three-dimensional map.

8) Surface elements: refers to three-dimensional map elements, such as buildings, vehicles, trees, etc., over geographic elements such as topography and topography in a three-dimensional map.

9) Elevation value is the vertical distance from a ground point to the elevation-starting surface of a surface element (e.g., the top surface of a building).

10 Geographic element): refers to three-dimensional map elements representing topography and topography in a three-dimensional map, such as mountains, rivers, lakes, etc.

In the implementation of the embodiments of the present application, the applicant found that the related art has the following problems:

in the construction process of the digital earth scene based on the real topography, a building is placed on the topography with the height, firstly, depending on the accuracy of the elevation value, when the accuracy of the elevation value is insufficient, the building is represented as having an elevation sampling point at intervals of a longer distance, in this case, the elevation value between different sampling points is unknown, when the building is placed, according to X, Y coordinate values of the center of the building, the sampling point closest to the center of the building on an XY plane is found, the elevation value of the sampling point is obtained, and the elevation value is assigned to the building.

Referring to fig. 4A, fig. 4A is a schematic diagram of a display method of a three-dimensional map in the related art. The center point of the building (i.e. the center point of the bottom surface described above) is located at the point E, and the distance from the point E to the point a, the distance from the point B, the distance from the point C, and the distance from the point D are calculated, so that the point a closest to the point E is found, the elevation value of the point a is known, the elevation value of the point a is given to the point E, and the elevation value of the building is given.

According to the elevation values obtained by the related art, if the resolution between the elevation value sampling points is low, such as 30 meters, or 90 meters, the elevation value of the building bottom surface located between the four sampling points can only be obtained, any one of the elevation values of the A, B, C, D four sampling points can only be obtained, and since the range of the elevation value of the building bottom surface located between the four sampling points is A, B, C, D, if the elevation value of the topography between the four sampling points is significantly higher than the elevation value of each of the A, B, C, D four sampling points, or significantly lower than the elevation value of each of the A, B, C, D four sampling points, the elevation value of the building bottom surface and the elevation value of the topography can be seriously different, so that the building bottom surface and the topography can be poorly matched, and the visual effect of the building on the topography or buried under the ground can be caused. By the three-dimensional map display method, the elevation value precision in the three-dimensional map can be improved, and therefore accurate attachment of the terrain background and the surface elements is achieved.

The embodiments of the present application provide a method, an apparatus, an electronic device, a computer readable storage medium, and a computer program product for displaying a three-dimensional map, which can improve the accuracy of elevation values in the three-dimensional map, so as to implement accurate attachment of a terrain background and a surface element, and hereinafter describe an exemplary application of the electronic device provided by the embodiments of the present application, where the electronic device provided by the embodiments of the present application may be implemented as a notebook computer, a tablet computer, a desktop computer, a set-top box, a mobile device (for example, a mobile phone, a portable music player, a personal digital assistant, a dedicated message device, a portable game device), a vehicle-mounted terminal, or any other user terminal, and may also be implemented as a server.

Referring to fig. 1, fig. 1 is a schematic diagram of an optional architecture of a three-dimensional map display processing system 100 provided in an embodiment of the present application, in order to implement an application scenario of three-dimensional map display (for example, displaying a three-dimensional map in a network game, displaying a three-dimensional map in a navigation APP of an in-vehicle terminal, etc.), a terminal (a terminal 400 is shown in an example) is connected to a server 200 through a network 300, where the network 300 may be a wide area network or a local area network, or a combination of the two.

The terminal 400 is configured for display on a graphical interface 410-1 (graphical interface 410-1 is shown for example) for use by a user using a client 410. The terminal 400 and the server 200 are connected to each other through a wired or wireless network.

In some embodiments, the server 200 may be an independent physical server, a server cluster or a distributed system formed by a plurality of physical servers, or a cloud server that provides cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, CDNs, and basic cloud computing services such as big data and artificial intelligence platforms. The terminal and the server may be directly or indirectly connected through wired or wireless communication, which is not limited in the embodiments of the present application.

In some embodiments, the terminal 400 obtains map data based on the digital elevation model from the server 200, and a client 410 (e.g., an electronic map client, a navigation client) in the terminal 400 draws a map using a built-in engine and displays the drawn three-dimensional map in the graphical interface 410-1.

In some embodiments, the terminal 400 obtains three-dimensional coordinate data of grid vertices of a plurality of grids in a terrain background and two-dimensional coordinates of a bottom surface center point of a surface element from the server 200, the terminal 400 draws the terrain background in a three-dimensional map, the terminal 400 determines an elevation value of the bottom surface center point of the surface element, draws the surface element in the three-dimensional map, and displays the terrain background and the surface element of the drawn three-dimensional map in the graphical interface 410-1.

In some embodiments, taking an example that an electronic device is a terminal device, referring to fig. 2, fig. 2 is a schematic structural diagram of a terminal 400 provided in an embodiment of the present application, and the terminal 400 shown in fig. 2 includes: at least one processor 410, a memory 450, at least one network interface 420, and a user interface 430. The various components in terminal 400 are coupled together by a bus system 440. It is understood that the bus system 440 is used to enable connected communication between these components. The bus system 440 includes a power bus, a control bus, and a status signal bus in addition to the data bus. But for clarity of illustration the various buses are labeled in fig. 2 as bus system 440.

The processor 410 may be an integrated circuit chip having signal processing capabilities such as a general purpose processor, such as a microprocessor or any conventional processor, or the like, a digital signal processor (DSP, digital Signal Processor), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or the like.

The user interface 430 includes one or more output devices 431, including one or more speakers and/or one or more visual displays, that enable presentation of the media content. The user interface 430 also includes one or more input devices 432, including user interface components that facilitate user input, such as a keyboard, mouse, microphone, touch screen display, camera, other input buttons and controls.

Memory 450 may be removable, non-removable, or a combination thereof. Exemplary hardware devices include solid state memory, hard drives, optical drives, and the like. Memory 450 optionally includes one or more storage devices physically remote from processor 410.

Memory 450 includes volatile memory or nonvolatile memory, and may also include both volatile and nonvolatile memory. The nonvolatile Memory may be a Read Only Memory (ROM), and the volatile Memory may be a random access Memory (RAM, random Access Memory). The memory 450 described in the embodiments herein is intended to comprise any suitable type of memory.

In some embodiments, memory 450 is capable of storing data to support various operations, examples of which include programs, modules and data structures, or subsets or supersets thereof, as exemplified below.

An operating system 451 including system programs, e.g., framework layer, core library layer, driver layer, etc., for handling various basic system services and performing hardware-related tasks, for implementing various basic services and handling hardware-based tasks;

a network communication module 452 for accessing other electronic devices via one or more (wired or wireless) network interfaces 420, the exemplary network interface 420 comprising: bluetooth, wireless compatibility authentication (WiFi), and universal serial bus (USB, universal Serial Bus), etc.;

a presentation module 453 for enabling presentation of information (e.g., a user interface for operating peripheral devices and displaying content and information) via one or more output devices 431 (e.g., a display screen, speakers, etc.) associated with the user interface 430;

an input processing module 454 for detecting one or more user inputs or interactions from one of the one or more input devices 432 and translating the detected inputs or interactions.

In some embodiments, the display device for a three-dimensional map provided in the embodiments of the present application may be implemented in a software manner, and fig. 2 shows a display device 455 for a three-dimensional map stored in a memory 450, which may be software in the form of a program and a plug-in, and includes the following software modules: the first drawing module 4551, the first determination module 4552, the second determination module 4553, and the second drawing module 4554 are logical, and thus may be arbitrarily combined or further split according to the functions implemented. The functions of the respective modules will be described hereinafter.

In some embodiments, the terminal or the server may implement the method for displaying a three-dimensional map provided in the embodiments of the present application by running a computer program. For example, the computer program may be a native program or a software module in an operating system; it may be a local (Native) Application program (APP), i.e. a program that needs to be installed in an operating system to run, such as a map navigation APP, a game APP.

The method for displaying the three-dimensional map provided by the embodiment of the application will be described in connection with an exemplary application and implementation in which the electronic device provided by the embodiment of the application is a terminal.

Referring to fig. 3A, fig. 3A is a flowchart of a three-dimensional map display method according to an embodiment of the present application, and will be described with reference to steps 101 to 105 shown in fig. 3A.

In step 101, a terrain background in a three-dimensional map is drawn based on three-dimensional coordinate data of grid vertices of a plurality of grids in the terrain background.

In some embodiments, the three-dimensional map includes a topographical background, which is a component of the three-dimensional map that characterizes the surface relief morphology and the geographic location, shape. The three-dimensional coordinate data of the mesh vertices may be (x) _i ，y _i ，z _i )。

As an example, referring to fig. 4D, the schematic diagram of the three-dimensional map display method provided in the embodiment of fig. 4D, three-dimensional coordinate data of each grid vertex in the grid may be determined by mapping, setting, and the like, and three-dimensional coordinate data between grid vertices in the grid may not be determined by mapping, setting, and the like due to limitation of factors such as mapping precision or sampling precision.

In some embodiments, the terrain background in the three-dimensional map is rendered by a rendering thread of an Engine (UE 4), based on three-dimensional coordinate data of grid vertices of a plurality of grids in the terrain background.

In some embodiments, referring to fig. 3B, fig. 3B is a flow chart of a method for displaying a three-dimensional map according to an embodiment of the present application. Before determining at least two candidate planes in the target mesh based on the three-dimensional coordinate data of mesh vertices of the target mesh, i.e. before step 102, after step 101, the target mesh in which the surface element is located in the plurality of meshes may be determined by performing steps 106 to 107.

In step 106, the two-dimensional coordinates of the bottom surface center point of the surface element are matched with the coordinate ranges corresponding to the grids, and the grid matched with the two-dimensional coordinates of the bottom surface center point is determined.

In some embodiments, a surface element refers to a three-dimensional map element above a geographic element such as a topography in a three-dimensional map, e.g., a building, a vehicle, a tree in a three-dimensional map.

As an example, referring to fig. 4D, 10×10 grids schematically shown in fig. 4D, two-dimensional coordinates (x, y) of a bottom surface center point E of a surface element are matched with coordinate ranges corresponding to the 10×10 grids, and a grid matched with the two-dimensional coordinates of the bottom surface center point E is determined as a grid ABCD.

In some embodiments, the plurality of grids are arranged in a plurality of rows and columns. Referring to fig. 4D, 10×10 grids shown in fig. 4D are distributed in 10 rows and 10 columns.

Therefore, three-dimensional coordinate data of grid vertexes are obtained by determining grids matched with the two-dimensional coordinates of the bottom surface center points, the follow-up determination of a target plane is facilitated, and the elevation value of the bottom surface center points of the surface elements is determined according to the target plane, so that a data foundation is laid for accurately determining the elevation value of the bottom surface center points of the surface elements.

In some embodiments, referring to fig. 3B, fig. 3B is a flow chart of a method for displaying a three-dimensional map according to an embodiment of the present application. In step 106, the two-dimensional coordinates of the bottom surface center point of the surface element are matched with the coordinate ranges corresponding to the multiple grids, and the grids matched with the two-dimensional coordinates of the bottom surface center point are determined by executing steps 1061 to 1063.

In step 1061, the abscissa of the bottom center point of the surface element is matched with the abscissa range corresponding to each row of grids, and the target grid row in which the surface element is located in the multiple grids is determined.

As an example, referring to fig. 4D, the abscissa x of the bottom center point E of the surface element is matched with the abscissa range corresponding to each row of grids, and the target grid row where the surface element is located in the multiple grids is determined, and the target grid row where the bottom center point E of the surface element in fig. 4D is located may be 5 rows.

In step 1062, the ordinate of the bottom center point of the surface element is matched with the ordinate range corresponding to each grid column, and the target grid column where the surface element is located in the multiple grids is determined.

As an example, referring to fig. 4D, the ordinate y of the bottom center point E of the surface element is matched with the ordinate range corresponding to each column of grids, and the target grid column where the surface element is located in the multiple grids is determined, and the target grid column where the bottom center point E of the surface element in fig. 4D is located may be 4 columns.

In step 1063, a grid matching the two-dimensional coordinates of the bottom surface center point is determined from the intersecting grids of the target grid columns and the target grid rows.

As an example, referring to fig. 4D, a grid matching the two-dimensional coordinates of the bottom surface center point is determined from the intersecting grid (5 rows and 4 columns, i.e., grid ABCD) of the target grid column (4 columns in fig. 4D) and the target grid row (5 rows in fig. 4D).

In some embodiments, referring to fig. 3C, fig. 3C is a flow chart of a method for displaying a three-dimensional map according to an embodiment of the present application. The determining of the grid matching the two-dimensional coordinates of the bottom surface center point according to the intersecting grid of the target grid column and the target grid row in step 1063 may be performed by executing step 10631A.

In step 10631A, the intersection grid of the target grid column and the target grid row is determined as a grid matching the two-dimensional coordinates of the bottom surface center point.

As an example, referring to fig. 4D, an intersecting grid (5 rows and 4 columns, i.e., grid ABCD) of a target grid column (4 columns in fig. 4D) and a target grid row (5 rows in fig. 4D) is determined as a grid matching the two-dimensional coordinates of the bottom surface center point.

Therefore, the intersecting grids of the target grid columns and the target grid rows are determined to be grids matched with the two-dimensional coordinates of the bottom surface center points, so that three-dimensional coordinate data of grid vertexes are obtained, the subsequent determination of a target plane is facilitated, the elevation value of the bottom surface center points of the surface elements is determined according to the target plane, and a data foundation is laid for accurately determining the elevation value of the bottom surface center points of the surface elements.

In other embodiments, referring to fig. 3C, determining a grid matching the two-dimensional coordinates of the bottom surface center point according to the intersecting grid of the target grid column and the target grid row in step 1053 may also be implemented by performing steps 10631B through 10632B.

In step 10631B, the sub-grids in which the surface element is located in the intersecting grid are determined from the intersecting grid of the target grid column and the target grid row.

As an example, referring to fig. 4H, from the intersecting grid ABCD of the target grid row and target grid column, the sub-grid FGHI in which the surface element is located in the intersecting grid is determined.

In some embodiments, step 10631B above determines the sub-grid in which the surface element is located in the intersecting grid from the intersecting grid of the target grid column and the target grid row, by: the method comprises the steps of conducting subdivision processing on intersecting grids of a target grid column and a target grid row to obtain a plurality of sub-grids in the intersecting grids; matching the abscissa of the bottom surface center point of the earth surface element with the abscissa range corresponding to each row of sub-grids, and determining the target sub-grid row of the earth surface element in the plurality of sub-grids; matching the ordinate of the bottom surface center point of the surface element with the ordinate range corresponding to each column of sub-grids to determine the target sub-grid column of the surface element in the plurality of sub-grids; and determining the intersecting submesh of the target submesh column and the target submesh row as the submesh where the surface element is located in the intersecting submesh.

In some embodiments, the subdivision process may be a process of continuously dividing a grid into a plurality of sub-grids.

As an example, referring to fig. 4H, the intersecting grid ABCD of the target grid column and the target grid row is subjected to subdivision processing, resulting in a plurality of sub-grids in the intersecting grid, which may be 10×10 sub-grids in the intersecting grid ABCD as shown in fig. 4H. Matching the abscissa x of the bottom surface center point of the surface element with the abscissa range corresponding to each row of sub-grids (5-1 rows to 5-10 rows shown in fig. 4H), and determining the target sub-grid row (5-5 rows shown in fig. 4H) where the surface element is located in the plurality of sub-grids; the ordinate y of the bottom surface center point of the surface element is matched with the ordinate range corresponding to each column of sub-grids (4-1 columns to 4-10 columns shown in fig. 4H), and the target sub-grid column (4-4 columns shown in fig. 4H) where the surface element is located in the plurality of sub-grids is determined. The intersecting subgrid (4-4 columns, 5-5 rows) of the target subgrid column (4-4 columns shown in FIG. 4H) and the target subgrid row (5-5 rows shown in FIG. 4H) are determined as the subgrid (FGHI shown in FIG. 4H) in which the surface elements are located in the intersecting grid.

In step 10632B, the sub-grid is determined as a grid that matches the two-dimensional coordinates of the bottom surface center point.

As an example, referring to FIG. 4H, sub-grid FGHI is determined as a grid that matches the two-dimensional coordinates of the floor center point.

Therefore, the intersecting grids of the target grid columns and the target grid rows are subjected to subdivision processing, so that the position of the bottom surface center point of the surface element in the grid is determined more accurately, the accuracy of determining the elevation value of the bottom surface center point of the surface element is improved more effectively, and a more accurate data base is laid for realizing accurate attachment of the terrain background and the surface element.

In step 107, a grid matching the two-dimensional coordinates of the bottom surface center point is determined as a target grid in which the surface element is located in the plurality of grids.

As an example, referring to fig. 4D, a grid (grid ABCD) that matches the two-dimensional coordinates of the bottom surface center point is determined as a target grid in which the surface element is located among the multiple grids.

As an example, referring to fig. 4H, a grid (sub-grid FGHI) that matches the two-dimensional coordinates of the bottom surface center point is determined as a target grid in which the surface element is located among the multiple grids.

In step 102, at least two candidate planes are determined in the target mesh based on the three-dimensional coordinate data of the mesh vertices of the target mesh.

In some embodiments, the target mesh is a mesh in which the surface element to be rendered is located in a plurality of meshes.

In some embodiments, determining at least two candidate planes in the target mesh according to the three-dimensional coordinate data of the mesh vertices of the target mesh in step 102 may be implemented by: combining any three mesh vertices of the target mesh, performing the following processing for each of the resulting at least two combinations: candidate planes corresponding to the three mesh vertices in the combination are determined in the target mesh from the three-dimensional coordinate data of the three mesh vertices in the combination.

As an example, referring to fig. 4D, any three mesh vertices of the target mesh ABCD are combined, and the resulting at least two combinations may be ABC, ACD, BCD, ABD. The following processing is performed for each of the resulting at least two combinations: taking the combination ABC as an example, candidate planes corresponding to the three mesh vertices in the combination ABC are determined in the target mesh from three-dimensional coordinate data of the three mesh vertices (mesh vertex a, mesh vertex B, mesh vertex C) in the combination ABC.

As an example, three-dimensional coordinate data of three mesh vertices (mesh vertex a, mesh vertex B, mesh vertex C) in combination ABC may be: mesh vertex A (x _A ，y _A ，z _A ) The method comprises the steps of carrying out a first treatment on the surface of the Grid vertex B (x) _B ，y _B ，z _B ) The method comprises the steps of carrying out a first treatment on the surface of the Grid vertex C (x) _C ，y _C ，z _C ). Candidate planes corresponding to the three mesh vertices in the combination, plane ABC, are determined in the target mesh.

For example, referring to FIG. 4E, the plane equation for plane ABC is:

p(X-x _A )+q(Y-y _A )+r(Z-z _A )＝0 (1)

wherein, the normal vector of the plane ABC

The three-dimensional coordinate data of the mesh vertex a is (x) _A ，y _A ，z _A )。

By way of example, the normal vector of plane ABC

The determination may be made by: three-dimensional coordinate data (x) based on mesh vertex a _A ，y _A ，z _A ) Three-dimensional coordinate data (x _B ，y _B ，z _B ) Three-dimensional coordinate data (x _C ，y _C ，z _C ) Calculating the space vector +.>

And space vector->

Is a cross product of (a).

Wherein the space vector

The expression of (2) may be:

wherein the space vector

The expression of (2) may be:

space vector

And space vector->

The cross product of (c) can be expressed as:

wherein, the liquid crystal display device comprises a liquid crystal display device,

is a unit vector in the X-axis direction, +.>

Is a unit vector in the Y-axis direction, +.>

Is a unit vector in the Z-axis direction.

Vector space

And space vector->

Cross product of (A)>

Normal vector determined as plane ABC

I.e. < ->

In the same manner as the plane equation of plane ABC is determined, the plane equation of plane ACD may be:

α(X-x _A )+β(Y-y _A )+γ(Z-z _A )＝0 (5)

wherein, the normal vector of the plane ACD

In step 103, the candidate plane in which the surface element is located is determined as the target plane.

As an example, referring to fig. 4F, the candidate plane in which the surface element is located, i.e., the plane ACD shown in fig. 4F, is determined as the target plane.

In some embodiments, referring to fig. 3D, fig. 3D is a flow chart of a method for displaying a three-dimensional map according to an embodiment of the present application. Prior to step 103, steps 108 to 109 may be performed for each candidate plane determined to determine the candidate plane in which the surface element is located.

In step 108, for any one of the reference vertices on the candidate plane and the bottom center point of the surface element, determining a relative positional relationship with the reference vertices, wherein the relative positional relationship characterizes: and whether any one of the reference vertexes and the bottom center point of the surface element are positioned on the same side of the reference vector corresponding to the reference vertex.

In some embodiments, the reference vertex may be one of three grid vertices on the candidate plane that is not used to construct a reference vector, where the reference vertex is a grid vertex that is not used to construct a reference vector.

In some embodiments, referring to fig. 3D, fig. 3D is a flow chart of a method for displaying a three-dimensional map according to an embodiment of the present application. The above-mentioned step 108 may be implemented by performing steps 1081 to 1086 to determine the relative positional relationship with the reference vertex with respect to any one of the reference vertex and the bottom center point of the surface element on the candidate plane.

In step 1081, any two mesh vertices are selected from among the three mesh vertices on the candidate plane to construct a reference vector, and one mesh vertex that is not used to construct the reference vector is taken as a reference vertex.

As an example, referring to fig. 4G, taking plane candidate ABC as an example, among three mesh vertices (i.e., mesh vertex a, mesh vertex B, mesh vertex C) on plane candidate ABC, mesh vertex a and mesh vertex B are selected to construct a reference vector

Taking a grid vertex C which is not used for constructing the reference vector as a reference vertex; selecting grid vertex B and grid vertex C to construct reference vector +.>

Taking a grid vertex A which is not used for constructing the reference vector as a reference vertex; selecting grid vertex A and grid vertex C to construct reference vector +.>

One mesh vertex B not used for constructing the reference vector is taken as a reference vertex.

In step 1082, any one of the mesh vertices is selected from the reference vector as the reference vertex.

As an example, see fig. 4G, at reference vector

Selecting a grid vertex B or a grid vertex A as a reference vertex; alternatively, in the reference vector->

Selecting a grid vertex B or a grid vertex C as a reference vertex; alternatively, reference vector

And selecting the grid vertex A or the grid vertex C as a reference vertex.

In step 1083, a reference vector is constructed based on the base vertices and the reference vertices, and a surface element vector is constructed based on the base center points of the surface elements and the base vertices.

As an example, see fig. 4G, when the reference vector is

In this case, the reference vertex is the grid vertex C, and the reference vertex may be the grid vertex a or the grid vertex B, and the reference vertex is the grid vertex a. Constructing a reference vector based on the base vertex (mesh vertex A) and the reference vertex (mesh vertex C)>

Constructing a ground element vector +/based on a ground element's bottom center point E and a reference vertex (mesh vertex A)>

In step 1084, performing cross product processing on the reference vector and the surface element vector to obtain a first cross product processing result; and carrying out cross product processing on the reference vector and the reference vector to obtain a second cross product processing result.

As an example, see fig. 4G, a bearingIn the above example, when the reference vector is

When the earth surface element vector is +.>

The reference vector is +.>

Reference vector +.>

And surface element vector->

Performing cross product processing to obtain a first cross product processing result, wherein the first cross product processing result is +.>

The expression of (2) may be:

as an example, referring to fig. 4G, reference vectors will be

And reference vector->

And performing cross product processing to obtain a second cross product processing result. Wherein, the expression of the second binary product processing result ω may be: />

in step 1085, when the first and second cross product processing results are in agreement, it is determined that the reference vertex and the bottom center point of the surface element are located on the same side of the reference vector.

As an example, see fig. 4G, when the first cross product process results

And a second binary product processing result

When the directions are consistent, determining that the reference vertex (grid vertex C) and the bottom center point E of the surface element are positioned in the reference vector +.>

Is the same side of (a).

In step 1086, when the first and second cross product processing results are not in agreement, it is determined that the reference vertex and the bottom center point of the surface element are located on different sides of the reference vector.

As an example, referring to fig. 4G, when the bottom surface center point of the surface element is the Q point, the first cross product processing results

And second binary product processing result->

Direction inconsistency, determining a reference vertex (mesh vertex C) and a bottom surface of a surface elementThe center point Q is located at the reference vector +.>

Is provided.

In step 109, when each of the reference vertex and the bottom center point of the surface element is located on the same side of the reference vector corresponding to the reference vertex, the candidate plane is determined to be the candidate plane where the surface element is located.

As an example, referring to fig. 4G, when the reference vertex (mesh vertex C) and the bottom surface center point E of the surface element are located at the reference vector corresponding to the reference vertex (mesh vertex C)

And the reference vertex (grid vertex B) and the bottom center point E of the surface element are located at the reference vector +.>

And the reference vertex (grid vertex A) and the bottom center point E of the ground surface element are positioned at the reference vector +.>

And determining the candidate plane ABC as the candidate plane where the surface element is located.

Therefore, the candidate plane where the surface element is located can be accurately determined, the accuracy of the elevation value of the determined bottom surface center point of the surface element is more effectively improved, and a more accurate data base is laid for realizing accurate attachment of the terrain background and the surface element.

In step 104, an elevation value of the subsurface center point of the surface element is determined based on the two-dimensional coordinates of the subsurface center point of the surface element and the target plane.

In some embodiments, the elevation value of the subsurface center point of the surface element may be representative of the elevation of the subsurface center point of the surface element, i.e., the vertical axis coordinates of the subsurface center point of the surface element in a spatial planar rectangular coordinate system.

As an example, the elevation value z of the subsurface center point of the surface element is determined based on the two-dimensional coordinates (x, y) of the subsurface center point E of the surface element and the target plane (e.g., candidate plane ABC).

In some embodiments, determining the elevation value of the bottom surface center point of the surface element based on the two-dimensional coordinates of the bottom surface center point of the surface element and the target plane in step 104 may be achieved by: calling a plane equation of a target plane based on the two-dimensional coordinates of the bottom surface center point to obtain an elevation value of the bottom surface center point of the earth surface element; the plane equation of the target plane represents the mapping relation between the two-dimensional coordinates of the bottom surface center point and the elevation value of the bottom surface center point.

As an example, when the target plane is plane ABC, the plane equation for the target plane may be:

p(X-x _A )+q(Y-y _A )+r(Z-z _A )＝0 (8)

as an example, a plane equation p (X-X) of the target plane is called based on the two-dimensional coordinates (X, y) of the ground center point E of the ground surface element _A )+q(Y-y _A )+r(Z-z _A ) =0, resulting in an elevation value z of the bottom surface center point of the surface element. Namely, let X=x, Y=y in the plane equation, calculate and get the value of Z, assign Z value to elevation value Z.

In this way, since the elevation value of the bottom surface center point of the surface element is determined based on the target plane, when the two-dimensional coordinates of the bottom surface center point of the surface element are changed, the determined elevation range of the bottom surface center point of the surface element is the definition domain of the target plane, that is, the determined elevation value of the bottom surface center point of the surface element continuously changes along with the change of the two-dimensional coordinates of the bottom surface center point of the surface element, thereby effectively improving the accuracy of the determined elevation value of the bottom surface center point of the surface element.

In step 105, the surface element is plotted at a location in the terrain background that coincides with the bottom surface center point, based on the elevation value of the bottom surface center point of the surface element.

In some embodiments, the surface element is rendered at a floor center point in the terrain background by a rendering thread of an Engine (UE 4) according to an elevation value of the floor center point of the surface element.

As an example, a surface element is plotted at a floor center point E (x, y) in a topographical background from the elevation value z of the floor center point E of the surface element. The position in the topographic background that coincides with the bottom surface center point refers to the position in the topographic background that has the same three-dimensional coordinate data as the bottom surface center point of the surface element.

In this way, by determining the grid in which the surface element to be rendered is located in the multiple grids in the terrain background, namely the target grid, a candidate plane in which the surface element is located, namely the target plane, is determined according to the three-dimensional coordinate data of the grid vertices of the target grid. Because the elevation value of the bottom surface center point of the surface element is determined based on the target plane, when the two-dimensional coordinates of the bottom surface center point of the surface element are changed, the value range of the elevation value of the bottom surface center point of the surface element is the definition domain of the target plane, namely, the value of the elevation value of the bottom surface center point of the surface element is continuously changed along with the change of the two-dimensional coordinates of the bottom surface center point of the surface element, thereby effectively improving the precision of the elevation value of the bottom surface center point of the surface element, and further drawing the surface element at the position which coincides with the bottom surface center point in the terrain background according to the elevation value of the bottom surface center point of the surface element, so that the precise fitting of the terrain background and the surface element is realized.

Next, an exemplary application of the embodiment of the present application in an application scenario of display of an actual three-dimensional map will be described. In an application scene of displaying an actual three-dimensional map, building and displaying of the three-dimensional map scene are generally required to be achieved by drawing a terrain background and surface elements. For the construction and display of a three-dimensional map scene, only determining the two-dimensional coordinates of the to-be-placed position of the surface element can lead to the fact that the placed surface element cannot be accurately attached to the terrain background, because the elevation value is absent in the plane coordinates, the elevation value of the surface element and the elevation value of the terrain background cannot be unified, the virtual surface element and the upper side of the terrain background are caused or sink to the to-be-placed position on the visual effect, and user experience is seriously affected. By the three-dimensional map display method, the elevation value of the bottom surface center point of the surface element can be accurately determined, so that the surface element is placed at the accurate terrain background, the surface element and the terrain background are accurately attached, and user experience is improved.

In some embodiments, the terrain triangle mesh (i.e. the mesh described above) can be programmatically constructed by an Engine (un real Engine 4, ue 4), and by constructing a spatial plane equation (i.e. the plane equation described above), the elevation value z of the spatial plane equation is accurately obtained under the condition that the plane coordinates (x, y) are known, so that continuous interpolation calculation in a local space is realized, accurate fitting of the virtual component (i.e. the surface element described above) and the position to be placed can be realized, and user experience is improved.

In some embodiments, referring to fig. 4F, fig. 4F is a schematic diagram of a three-dimensional map display method according to an embodiment of the present application. Obtaining a space plane equation of a space plane ABC according to the space coordinates of the sampling point (namely the grid vertex) A, the sampling point B and the sampling point C; and obtaining a space plane equation of the space plane ADC according to the space coordinates of the sampling point A, the sampling point D and the sampling point C. Judging the space plane where the point E is located, substituting the plane coordinates (x, y) of the point E into a space plane equation of the space plane ABC when the point E is in the space plane ABC to obtain an elevation value z of the point E; when the point E is in the space plane ADC, the plane coordinates (x, y) of the point E are substituted into the space plane equation of the space plane ADC, and the elevation value z of the point E is obtained. The linear change of the elevation value can be accurately reflected by the space plane equation, when the plane coordinates (x, y) of the point E change, the elevation value solved based on the space plane equation can also linearly change along with the change of the plane coordinates of the point E, so that continuous linear interpolation between sampling points is realized, the point E located between the sampling points A, B, C and D is located, and the elevation value z of the point E is uniquely determined under the condition that the plane coordinates of the point E are known, therefore, the elevation value of any point can be accurately obtained under the condition that the plane coordinates of any point are known, and the accurate attachment of the virtual component and the position to be placed can be realized.

In some embodiments, referring to fig. 4B, as shown in fig. 4B, in a real scene of the digital earth, in the digital earth drawn based on the game engine (UE 4), the digital earth truly draws a triangular network of mountains according to elevation values, and in order to make the relief of the building 41 and the topography 42 better match, it is necessary to make the bottom surface of the building 41 better fit the relief topography 42. The embodiment of the present application obtains the elevation value of the building 41 (i.e., the above-described surface elements) between the sampling points by calculating the spatial plane equation, and assigns the elevation value to the building 41, so that the building 41 is better fitted with the terrain 42. By the three-dimensional map display method provided by the embodiment of the application, the problem that the building 41 and the terrain 42 (namely the terrain background described above) cannot be accurately fused when the digital earth is drawn based on the game engine can be effectively solved.

In some embodiments, the center point of the bottom surface of the building is calculated to be located on a specific rectangular grid, namely, the grid on which the longitude and latitude (x, y) of the building is located is calculated, and then the space Cartesian coordinates X, Y, Z of the four vertexes of the longitude and latitude grid are obtained by obtaining the row-column coordinate index of the grid. In a Cartesian coordinate system, three vertices in space that are not collinear may determine a unique plane of space, i.e., a point French plane equation determined by three points in space that are not collinear is calculated. After a space plane equation of the coordinates of the bottom surface center point of the building is determined, the height value Z of the building on the plane can be calculated, the height value is given to the building, and the building can be attached along the terrain.

In some embodiments, referring to fig. 4C, fig. 4C is a flow chart of a method for displaying a three-dimensional map according to an embodiment of the present application. The description will be made with reference to steps 401 to 406 shown in fig. 4C.

In step 401, a grid of building latitude and longitude locations is calculated.

As an example, referring to fig. 4D, fig. 4D is a schematic diagram of a three-dimensional map display method provided in an embodiment of the present application. The grid on which the longitude and latitude (x, y) of the building E sits is grid ABCD. The terrain may be plotted based on a digital elevation model (Digital Elevation Model, DEM) to form a terrain mesh as shown in fig. 4D, where points a, B, C, D are four sampling points of the terrain. Every fixed distance, there will be a sampling point, and each sampling point has an elevation value. The longitude and latitude intervals of the digital elevation model can be obtained by analyzing the topographic map of the image file format (Tag Image File Format, TIFF or TIF), and the obtained longitude and latitude intervals are used as fixed distances of intervals among sampling points. Thus, the grid position of the center point can be conveniently calculated, and the grid position can be described by rows and columns.

In some embodiments, the grid on which the building is located at longitude and latitude may be determined by: determining two rows of grid lines closest to the longitude of the building, and determining two columns of grid lines closest to the latitude of the building; four sampling points at which two rows of grid lines and two columns of grid lines intersect are determined as four vertexes of a grid where the longitude and latitude of the building are located.

In step 402, coordinate values of four vertices of the mesh are acquired.

As an example, referring to fig. 4D, the coordinate value of the vertex a in the mesh ABCD may be (x _A ，y _A ，z _A ) The coordinate value of the vertex B may be (x) _B ，y _B ，z _B ) The coordinate value of the vertex C may be (x) _C ，y _C ，z _C ) The coordinate value of the vertex D may be (x) _D ，y _D ，z _D )。

In step 403, the spatial plane equation for plane ABC and plane ADC is calculated.

As an example, according to the coordinate value (x _A ，y _A ，z _A ) Coordinate value of vertex B (x _B ，y _B ，z _B ) Coordinate value of vertex C (x _C ，y _C ，z _C ) Coordinate value of vertex D (x _D ，y _D ，z _D ) And calculating to obtain a space plane equation of the plane ABC and the plane ADC.

As an example, referring to fig. 4E, fig. 4E is a schematic diagram of a three-dimensional map display method provided in an embodiment of the present application. The calculation mode of the space plane equation of the plane ABC and the plane ADC can be as follows: the vector is used as a tool to calculate a space plane equation in a space rectangular coordinate system XYZ. Since any point in the excess space can and only can be made a plane perpendicular to the known straight line, in the plane ABC, the coordinate values of three points (vertex a, vertex B, and vertex C) in the plane ABC are known, and the normal vector of the plane ABC is known

The point French equation for plane ABC may be:

p(X-x _A )+q(Y-y _A )+r(Z-z _A )＝0 (9)

The calculation mode of the point French equation of the plane ACD is the same as the principle of the calculation mode of the point French equation of the plane ABC.

For example, see FIG. 4E, the normal vector to plane ABC

The determination may be made by: coordinate value (x) based on vertex a _A ，y _A ，z _A ) Coordinate value of vertex B (x _B ，y _B ，z _B ) Coordinate value of vertex C (x _C ，y _C ，z _C ) Calculating the space vector +.>

And space vector->

Is a cross product of (a).

Space vector

The expression of (2) may be:

space vector

The expression of (2) may be:

space vector

And space vector->

The cross product of (c) can be expressed as:

vector space

And space vector->

Cross product of (A)>

Is determined as->

I.e.

In step 404, it is determined whether the building floor center point is within plane ABC.

As an example, referring to fig. 4F, it is determined which plane equation the building floor center point belongs to, i.e., whether the building floor center point belongs to plane ABC or plane ADC plane equation. The judging mode for judging whether the center point of the bottom surface of the building is in the plane ABC is as follows: and judging whether the center point E of the building bottom surface is positioned in the triangle ABC or not, so as to judge whether the center point E of the building bottom surface belongs to the plane ABC or not.

As an example, referring to fig. 4G, when walking on three sides in the direction of ABCA, point E is always located to the right of sides AB, BC and CA. Therefore, when the line segment AB is selected, the point C is located on the right side of AB, and when BC is selected, the point a is located on the right side of BC, and when CA is selected finally, the point B is located on the right side of CA, so when a certain side is selected, only the point E and the point opposite to the side need to be verified.

As an example, referring to fig. 4G, two points are judged to be on the same side of a certain line segment by cross product, EA or QA is connected, EA and AB are cross product, CA and AB are cross product, if the result directions of the two cross products are consistent, the two points are on the same side, i.e. point E and point C are on the same side of AB. Similarly, it can be calculated whether point E and point A are on the same side, i.e., whether point E and point A are on the same side of BC, and whether point E and point B are on the same side, i.e., whether point E and point B are on the same side of AC.

As an example, referring to fig. 4G, if and only if point E is on the same side of BC as point a, point E is on the same side of AC as point B, point E is satisfied simultaneously with point C on the same side of AB, it may be determined that point E is inside triangle ABC, otherwise outside.

In step 405, when the center point is within plane ABC, the elevation value z is calculated by taking the latitude and longitude coordinates (x, y) into the spatial plane equation of plane ABC.

As an example, when the center point of the bottom surface of the building is in the plane ABC, the longitude and latitude coordinates (x, y) of the center point of the bottom surface of the building are brought into the space plane equation of the plane ABC, the result z is obtained, the result z is determined as the elevation value z of the center point of the bottom surface of the building, and finally the fitting of the building and the terrain is achieved.

In step 406, when the center point is within the planar ADC, the elevation value z is calculated by taking the longitude and latitude coordinates (x, y) into the spatial plane equation of the planar ADC.

As an example, when the center point of the bottom surface of the building is in the plane ADC, the longitude and latitude coordinates (x, y) of the center point of the bottom surface of the building are brought into the space plane equation of the plane ADC, a result z is obtained, and the result z is determined as the elevation value z of the center point of the bottom surface of the building, so that the fitting of the building and the terrain is finally achieved.

In some embodiments, referring to fig. 4B, by the three-dimensional map display method provided in the embodiments of the present application, in the case that the accuracy of the elevation value is insufficient, a continuous elevation value (i.e. the elevation value described above) that is linearly interpolated for the center point of the bottom surface of the building 41 that is sitting on the terrain 42 is obtained, and the elevation value is given to the building 41, so as to achieve better fitting between the building and the terrain. The capping phenomenon or floating phenomenon occurring when the building 41 and the terrain 42 are fused can be effectively avoided, so that the fusion of the building and the terrain approximates to the real display effect.

In some embodiments, referring to fig. 4H, in performing interpolation computation, sampling points with lower precision may be subdivided into finer triangular grids by way of subdivision grids, and in this way, discrete linear interpolation computation is implemented, where point a, point B, point C, and point D are sampling points with elevation values, point E is a grid between the bottom center points of the building and A, B, C, D, and is a grid that needs to be subdivided when calculating elevation values (i.e., the elevation values described above).

In some embodiments, referring to fig. 4I, fig. 4I is a flow chart of a method for displaying a three-dimensional map according to an embodiment of the present application. The description will be made with reference to steps 407 to 411 shown in fig. 4I.

In step 407, a grid of building latitude and longitude seats is calculated.

In step 408, a fine mesh is finely meshed according to the custom interval.

In step 409, a grid is calculated at which the points in the coordinates of the floor of the building are located.

In step 410, the rank coefficient ratios of the seated mesh are calculated, respectively.

In step 411, the height value is calculated by the row and column coefficient ratio, and the average value of the sum of the row and column height values is taken as the elevation value of the bottom center point of the building.

After step 411, the building may be drawn at the floor center point in the terrain by a drawing thread of the Engine (UE 4) according to the elevation value of the floor center point of the building.

Continuing with the description below of an exemplary structure of the display device 455 for three-dimensional maps provided in embodiments of the present application implemented as software modules, in some embodiments, as shown in fig. 2, the software modules stored in the display device 455 for three-dimensional maps of the memory 450 may include: a first drawing module 4551 for drawing a terrain background in a three-dimensional map based on three-dimensional coordinate data of grid vertices of a plurality of grids in the terrain background; a first determining module 4552, configured to determine at least two candidate planes in a target mesh according to three-dimensional coordinate data of mesh vertices of the target mesh, and determine a candidate plane in which a surface element is located as a target plane, where the target mesh is a mesh in which the surface element to be rendered is located in multiple meshes; a second determining module 4553, configured to determine an elevation value of the bottom surface center point of the surface element based on the two-dimensional coordinates of the bottom surface center point of the surface element and the target plane; and the second drawing module 4554 is configured to draw the surface element at a location in the terrain background coinciding with the bottom surface center point according to the elevation value of the bottom surface center point of the surface element.

In some embodiments, the display device 455 of the three-dimensional map further includes: the matching module is used for matching the two-dimensional coordinates of the bottom surface center point of the surface element with coordinate ranges corresponding to the grids and determining grids matched with the two-dimensional coordinates of the bottom surface center point; and the third determining module is used for determining the grid matched with the two-dimensional coordinates of the bottom surface center point as a target grid where the surface elements are located in the grids.

In some embodiments, the plurality of grids are arranged in a plurality of rows and columns; the matching module is further used for matching the abscissa of the bottom surface center point of the surface element with the corresponding abscissa range of each row of grids, and determining the target grid row of the surface element in the grids; matching the ordinate of the bottom surface center point of the earth surface element with the ordinate range corresponding to each grid column, and determining a target grid column of the earth surface element in the grids; and determining grids matched with the two-dimensional coordinates of the central point of the bottom surface according to the intersecting grids of the target grid columns and the target grid rows.

In some embodiments, the matching module is further configured to determine an intersecting grid of the target grid column and the target grid row as a grid matching the two-dimensional coordinates of the bottom surface center point; or determining the sub-grid where the surface element is located in the intersecting grid according to the intersecting grid of the target grid column and the target grid row; and determining the sub-grids as grids matched with the two-dimensional coordinates of the central point of the bottom surface.

In some embodiments, the matching module is further configured to subdivide an intersecting grid of the target grid column and the target grid row to obtain a plurality of sub-grids in the intersecting grid; matching the abscissa of the bottom surface center point of the earth surface element with the abscissa range corresponding to each row of sub-grids, and determining the target sub-grid row of the earth surface element in the plurality of sub-grids; matching the ordinate of the bottom surface center point of the surface element with the ordinate range corresponding to each column of sub-grids to determine the target sub-grid column of the surface element in the plurality of sub-grids; and determining the intersecting submesh of the target submesh column and the target submesh row as the submesh where the surface element is located in the intersecting submesh.

In some embodiments, the first determining module 4552 is further configured to combine any three mesh vertices of the target mesh, and perform, for each of the resulting at least two combinations, the following processing: candidate planes corresponding to the three mesh vertices in the combination are determined in the target mesh from the three-dimensional coordinate data of the three mesh vertices in the combination.

In some embodiments, the display device 455 of the three-dimensional map further includes: a fourth determining module, configured to determine, for any one of the reference vertices on the candidate plane and a bottom center point of the surface element, a relative positional relationship with the reference vertex, where the relative positional relationship is characterized by: whether any one of the reference vertexes and the bottom center point of the surface element are positioned on the same side of the reference vector corresponding to the reference vertex; and a fifth determining module, configured to determine the candidate plane as the candidate plane where the surface element is located when each reference vertex and the bottom center point of the surface element are located on the same side of the reference vector corresponding to the reference vertex.

In some embodiments, the fourth determining module is further configured to select any two mesh vertices from the three mesh vertices on the candidate plane to construct a reference vector, and use one mesh vertex that is not used to construct the reference vector as a reference vertex; selecting any grid vertex from the reference vector as a reference vertex; constructing a reference vector based on the reference vertex and the reference vertex, and constructing a surface element vector based on the base center point of the surface element and the reference vertex; performing cross product processing on the reference vector and the earth surface element vector to obtain a first cross product processing result; performing cross product processing on the reference vector and the reference vector to obtain a second cross product processing result; when the directions of the first cross product processing result and the second cross product processing result are consistent, determining that the center points of the reference vertexes and the bottom surfaces of the earth surface elements are positioned on the same side of the reference vector; when the directions of the first cross product processing result and the second cross product processing result are inconsistent, determining that the center points of the bottom surfaces of the reference vertexes and the surface elements are positioned on different sides of the reference vector.

In some embodiments, the second determining module 4553 is further configured to invoke a plane equation of the target plane based on the two-dimensional coordinates of the bottom surface center point to obtain an elevation value of the bottom surface center point of the surface element; the plane equation of the target plane represents the mapping relation between the two-dimensional coordinates of the bottom surface center point and the elevation value of the bottom surface center point.

The present embodiments provide a computer-readable storage medium storing executable instructions that, when executed by a processor, cause the processor to perform the method of displaying a three-dimensional map provided by the embodiments of the present application, for example, the method of displaying a three-dimensional map as shown in fig. 3A.

In some embodiments, the computer readable storage medium may be FRAM, ROM, PROM, EPROM, EEPROM, flash memory, magnetic surface memory, optical disk, or CD-ROM; but may be a variety of devices including one or any combination of the above memories.

In some embodiments, the executable instructions may be in the form of programs, software modules, scripts, or code, written in any form of programming language (including compiled or interpreted languages, or declarative or procedural languages), and they may be deployed in any form, including as stand-alone programs or as modules, components, subroutines, or other units suitable for use in a computing environment.

As an example, the executable instructions may, but need not, correspond to files in a file system, may be stored as part of a file that holds other programs or data, for example, in one or more scripts in a hypertext markup language (HTML, hyper Text Markup Language) document, in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files that store one or more modules, sub-programs, or portions of code).

As an example, executable instructions may be deployed to be executed on one electronic device or on multiple electronic devices located at one site or, alternatively, on multiple electronic devices distributed across multiple sites and interconnected by a communication network.

In summary, the following beneficial effects are provided by the embodiments of the present application:

(1) And determining a candidate plane where the surface element is located, namely a target plane, according to three-dimensional coordinate data of grid vertices of the target grid by determining the grid where the surface element to be rendered is located in a plurality of grids in the terrain background, namely the target grid. Because the elevation value of the bottom surface center point of the surface element is determined based on the target plane, when the two-dimensional coordinates of the bottom surface center point of the surface element are changed, the value range of the elevation value of the bottom surface center point of the surface element is the definition domain of the target plane, namely, the value of the elevation value of the bottom surface center point of the surface element is continuously changed along with the change of the two-dimensional coordinates of the bottom surface center point of the surface element, thereby effectively improving the precision of the elevation value of the bottom surface center point of the surface element, and further drawing the surface element at the position which coincides with the bottom surface center point in the terrain background according to the elevation value of the bottom surface center point of the surface element, so that the precise fitting of the terrain background and the surface element is realized.

(2) The three-dimensional coordinate data of the grid vertexes are obtained by determining the grids matched with the two-dimensional coordinates of the bottom surface center points, so that the subsequent determination of the target plane is facilitated, the elevation value of the bottom surface center points of the surface elements is determined according to the target plane, and a data foundation is laid for accurately determining the elevation value of the bottom surface center points of the surface elements.

(3) The intersecting grids of the target grid columns and the target grid rows are subjected to subdivision processing, so that the position of the bottom surface center point of the surface element in the grid is determined more accurately, the accuracy of the elevation value of the determined bottom surface center point of the surface element is improved more effectively, and a more accurate data base is laid for realizing accurate attachment of the terrain background and the surface element.

(4) By judging whether each reference vertex in each candidate plane and the bottom surface center point of the earth surface element are positioned on the same side of the reference vector corresponding to the reference vertex, the candidate plane where the earth surface element is positioned is determined, so that the candidate plane where the earth surface element is positioned can be accurately determined, the accuracy of the elevation value of the determined bottom surface center point of the earth surface element is more effectively improved, and a more accurate data base is laid for realizing accurate attachment of the terrain background and the earth surface element.

(5) Because the elevation value of the bottom surface center point of the surface element is determined based on the target plane, when the two-dimensional coordinates of the bottom surface center point of the surface element are changed, the determined elevation value range of the bottom surface center point of the surface element is the definition domain of the target plane, namely, the determined elevation value of the bottom surface center point of the surface element continuously changes along with the change of the two-dimensional coordinates of the bottom surface center point of the surface element, so that the accuracy of the determined elevation value of the bottom surface center point of the surface element is effectively improved.

The foregoing is merely exemplary embodiments of the present application and is not intended to limit the scope of the present application. Any modifications, equivalent substitutions, improvements, etc. that are within the spirit and scope of the present application are intended to be included within the scope of the present application.

Claims

1. A method of displaying a three-dimensional map, the method comprising:

determining at least two candidate planes in a target grid according to three-dimensional coordinate data of grid vertices of the target grid, and determining the candidate planes where the surface elements are located as target planes, wherein the target grid is a grid where the surface elements to be rendered are located in the multiple grids;

2. The method of claim 1, wherein the determining at least two candidate planes in the target mesh is preceded by the determining based on three-dimensional coordinate data of mesh vertices of the target mesh, the method further comprising:

matching the two-dimensional coordinates of the bottom surface center point of the surface element with the coordinate ranges corresponding to the grids, and determining grids matched with the two-dimensional coordinates of the bottom surface center point;

and determining the grid matched with the two-dimensional coordinates of the bottom surface center point as a target grid in which the surface element is positioned in the grids.

3. The method of claim 2, wherein the step of determining the position of the substrate comprises,

the grids are arranged in a plurality of rows and columns;

the matching the two-dimensional coordinates of the bottom surface center point of the surface element with the coordinate ranges corresponding to the grids, and determining the grid matched with the two-dimensional coordinates of the bottom surface center point comprises the following steps:

Matching the abscissa of the bottom surface center point of the surface element with the abscissa range corresponding to each grid, and determining the target grid row of the surface element in the grids;

matching the ordinate of the bottom surface center point of the surface element with the ordinate range corresponding to each grid, and determining a target grid row in which the surface element is positioned in the grids;

and determining grids matched with the two-dimensional coordinates of the bottom surface center point according to the intersecting grids of the target grid columns and the target grid rows.

4. A method according to claim 3, wherein said determining a grid matching the two-dimensional coordinates of the bottom surface center point from the intersecting grid of the target grid column and the target grid row comprises:

determining an intersecting grid of the target grid column and the target grid row as a grid matched with the two-dimensional coordinates of the bottom surface center point; or alternatively, the process may be performed,

determining a sub-grid where the surface element is located in the intersecting grid according to the intersecting grid of the target grid column and the target grid row;

and determining the sub-grids as grids matched with the two-dimensional coordinates of the bottom surface center point.

5. The method of claim 4, wherein the determining the sub-grid in which the surface element is located in the intersecting grid from the intersecting grid of the target grid column and the target grid row comprises:

subdividing the intersecting grids of the target grid columns and the target grid rows to obtain a plurality of sub-grids in the intersecting grids;

matching the abscissa of the bottom surface center point of the earth surface element with the abscissa range corresponding to each row of the subgrid, and determining the target subgrid row of the earth surface element in the plurality of subgrids;

matching the ordinate of the bottom surface center point of the earth surface element with the ordinate range corresponding to each column of the subgrid, and determining a target subgrid column of the earth surface element in the plurality of subgrids;

and determining an intersecting sub-grid of the target sub-grid column and the target sub-grid row as a sub-grid where the surface element is located in the intersecting grid.

6. The method of claim 1, wherein the target mesh comprises four mesh vertices;

the determining at least two candidate planes in the target mesh according to the three-dimensional coordinate data of the mesh vertex of the target mesh comprises:

Combining any three mesh vertices of the target mesh, performing the following processing for each of the resulting at least two combinations:

and determining candidate planes corresponding to the three grid vertices in the combination in the target grid according to the three-dimensional coordinate data of the three grid vertices in the combination.

7. The method of claim 1, wherein prior to determining the candidate plane in which the surface element is located as the target plane, the method further comprises:

for each of the candidate planes determined, performing the following processing:

determining a relative position relation between any reference vertex on the candidate plane and a bottom surface center point of the surface element, wherein the relative position relation is characterized in that: whether any one of the reference vertexes and the bottom center point of the surface element are positioned on the same side of the reference vector corresponding to the reference vertex;

and when the reference vertex and the bottom surface center point of the earth surface element are positioned on the same side of the reference vector corresponding to the reference vertex, determining the candidate plane as the candidate plane of the earth surface element, wherein the reference vector is constructed by any two grid vertices, and the reference vertex is a grid vertex which is not used for constructing the reference vector.

8. The method of claim 7, wherein determining the relative positional relationship with any one of the reference vertices on the candidate plane and the bottom center point of the surface element comprises:

selecting any two grid vertexes from three grid vertexes on the candidate plane to construct a reference vector, and taking one grid vertex which is not used for constructing the reference vector as the reference vertex;

selecting any grid vertex from the reference vector as a reference vertex;

constructing a reference vector based on the reference vertex and the reference vertex, and constructing a surface element vector based on a bottom surface center point of the surface element and the reference vertex;

performing cross product processing on the reference vector and the surface element vector to obtain a first cross product processing result; performing cross product processing on the reference vector and the reference vector to obtain a second cross product processing result;

when the directions of the first cross product processing result and the second cross product processing result are consistent, determining that the reference vertex and the bottom center point of the surface element are positioned on the same side of the reference vector;

And when the directions of the first cross product processing result and the second cross product processing result are inconsistent, determining that the reference vertex and the bottom surface center point of the surface element are positioned on different sides of the reference vector.

9. The method of claim 1, wherein the determining the elevation value of the subsurface center point of the surface element based on the two-dimensional coordinates of the subsurface center point of the surface element and the target plane comprises:

calling a plane equation of the target plane based on the two-dimensional coordinates of the bottom surface center point of the surface element to obtain an elevation value of the bottom surface center point of the surface element;

the plane equation of the target plane represents a mapping relationship between the two-dimensional coordinates of the bottom surface center point and the elevation value of the bottom surface center point.

10. A display device for a three-dimensional map, the device comprising:

11. An electronic device, the electronic device comprising:

a memory for storing executable instructions;

a processor for implementing the method of displaying a three-dimensional map according to any one of claims 1 to 9 when executing the executable instructions or computer program stored in the memory.

12. A computer-readable storage medium storing executable instructions or a computer program, wherein the executable instructions when executed by a processor implement the method of displaying a three-dimensional map according to any one of claims 1 to 9.

13. A computer program product comprising a computer program or instructions which, when executed by a processor, implements the method of displaying a three-dimensional map according to any one of claims 1 to 9.