JP4550756B2 - Navigation system, route search server, terminal device, and map display method - Google Patents

Description

  The present invention relates to a communication type navigation system, a route search server, a terminal device, and a map display method for searching and guiding an optimum route from a departure place to a destination for pedestrians and automobile drivers. In particular, the present invention includes a polygon database in which roads and buildings are represented by polygons in order to display roads and surrounding buildings in three dimensions, and polygon data of a surface facing the viewpoint position of a terminal device is obtained from a route search server. The present invention relates to a navigation system, a route search server, a terminal device, and a map display method capable of displaying a map three-dimensionally while suppressing communication load by distributing to a terminal device.

  Conventionally, when visiting a destination place on an unknown land, the user arrives while checking the transportation, road, landmark and address drawn on the map by using a map book or the like. In a car equipped with a car navigation system (hereinafter simply referred to as a car navigation system), a guidance displayed on a monitor screen or a voice output guidance (navigation) by starting the car navigation system and inputting a destination. Information) was reached.

  The car navigation system uses a GPS (Global Positioning System), receives GPS signals transmitted from a plurality of GPS satellites orbiting the earth with a GPS antenna, and transmits the GPS signals to the GPS signals. The position is specified by analyzing the satellite position and clock information included. At least four GPS satellites are required. The single positioning accuracy of GPS is generally over 10 m, but it is improved to 5 m or less by adopting DGPS (Differential GPS). In particular, GPS receivers that are currently installed only in some mobile phones are now being installed in all models of mobile phones called third generation.

  Various technologies have been proposed for using mobile terminals having such a positioning function. For example, a navigation device (car navigation) for automobiles has been developed, and map / route information is obtained using a mobile phone as a terminal. A communication navigation system for pedestrians distributed from an information distribution server (route search server) has been proposed.

  In recent years, the performance of mobile communication terminal devices such as mobile phones and PHS has been dramatically improved, and multi-functionalization has been progressing. In particular, the data communication function is strengthened in addition to the call function, and various data communication services are provided to the user via the Internet. A navigation service is one of them, and a communication navigation system that provides route guidance from a current position to a destination for not only a driver of a car but also a mobile phone user has been put into practical use.

  A general navigation device, a route search device and a route search method used in a communication navigation system are disclosed in, for example, the following Patent Document 1 (Japanese Patent Laid-Open No. 2001-165681). This navigation system is configured to send information on a departure point and a destination from a portable navigation terminal to an information distribution server, and the information distribution server searches and guides a route that matches a search condition from road network and traffic network data. Has been. As the search condition, there are means for moving from the departure place to the destination, for example, walking, automobile, combined use of railroad and walking, and the route is searched as one of the search conditions.

  The information distribution server has roads (routes) of map data as nodes and nodes as the positions of inflection points, links connecting the nodes as links, and cost information (distance and required time) of all links as a database. ing. Then, the information distribution server sequentially searches for a link from the departure node to the destination node with reference to the database, and traces the node and link with the smallest cost information of the link as a guide route. The shortest route can be guided to the portable navigation terminal. As such a route search method, a method called label determination method or Dijkstra method is used. Patent Document 1 also discloses a route search method using this Dijkstra method.

  Generally, in a communication type navigation system, map information displayed by a terminal device is downloaded from a server device such as a route search server connected via a network. For example, the following Patent Document 2 (Japanese Patent Laid-Open No. 2003-247833) and Patent Document 3 (Japanese Patent Laid-Open No. 2003-232644) disclose inventions of such communication type car navigation devices and map data download methods. It is disclosed.

  The navigation device disclosed in Patent Document 2 allows a user to select and set whether or not to permit downloading of map information from a server while traveling in a vehicle, and is configured as follows. The When the terminal side needs the next map, if it is downloaded to the memory card, the map is displayed using this. If the next map information has not been downloaded and the map information is permitted to be downloaded, it is downloaded from the server and written into a memory card for use. However, when the download is not permitted, the wide area map originally stored in the memory card is used and the scale is reduced to reduce the display.

  In addition, the map data download method disclosed in the above-mentioned Patent Document 3 is the driving state of a car, such as whether it is a general road, a highway, near an interchange, high speed driving or low speed driving. According to the state, the map data transmitted from the download center is selected and downloaded. This suppresses a large amount of map data not necessarily required by the user from being transmitted from the download center side.

  By the way, a terminal device that has received a guidance route from an information distribution server such as a route search server is provided with a display means such as a liquid crystal display device, and displays a map and a guidance route on the display means as well as the current state of pedestrians and cars The position (current position of the terminal device) is displayed on the guidance route to guide pedestrians and cars to the destination. Generally, the map displayed on the display means is a plan view, that is, a display of a two-dimensional figure, but the building is simulated in order to make it easy to see the state of the plane bird's-eye view, landmarks and buildings with a sense of perspective. In particular, a method of displaying a bird's eye view expressed three-dimensionally and a method of displaying roads and buildings as a three-dimensional polygon image by the Z buffer method have been proposed.

  For example, the following Patent Document 4 (Japanese Patent Laid-Open No. 2001-27535) discloses a map display device that displays buildings and roads in three dimensions. In the map display device disclosed in Patent Document 2, when a three-dimensional map is displayed, the route guide line is shaded on the road and displayed three-dimensionally. When the route guide line is in a positional relationship hidden in the building, the overlapping portion of the route guide line is displayed in a different color from the non-overlapping portion. In particular, the display color of the route guide line and the display color of the building are drawn on a VRAM (video RAM) by a semi-transparent method in which pixels are alternately set, and the relative positional relationship between the route guide line and the building is shown. It is clarified to improve the visibility of the route guide line.

  In order to perform the display as described above, in the map display device disclosed in Patent Document 4, building shape data and height information are stored in the map data, and road shape data is also stored for three-dimensional intersections and the like. Has been. Based on this map data, a three-dimensional drawing of a three-dimensional intersection of a building or road is drawn on the drawing unit, and a desired image is drawn on the drawing unit when the vehicle travels and reaches a route guidance position. A predetermined voice is uttered to guide the user to the destination.

  Similarly, a map display system for displaying a three-dimensional three-dimensional map is disclosed in, for example, the following Patent Document 5 (Japanese Patent Laid-Open No. 2005-56075). In the map display system disclosed in Patent Document 5, the map data processing unit includes the original 3D map data, scene graph data expressing the data structure of the 3D map in a tree structure, and the 3D map. The map data display unit identifies the display area with reference to the scene graph, reads the drawing data corresponding to the specified display area, and performs display processing. It is configured to do.

  This map display system is configured to store map information having a large amount of data in an external storage device such as a DVD or HDD in order to perform a three-dimensional three-dimensional map display.

JP 2001-165681 A (FIGS. 1 and 2) Japanese Patent Laying-Open No. 2003-247833 (FIGS. 1 and 6) Japanese Patent Laying-Open No. 2003-232644 (FIG. 1) Japanese Patent Laying-Open No. 2001-27535 (FIG. 1, FIG. 4, paragraph [0054]) JP-A-2005-56075 (FIGS. 1, 2, and 4, paragraphs [0056] to [0059])

  In the navigation system, an optimum route from a desired departure point to a destination is searched based on map data, and a guidance route is specified. Then, the current position is measured by positioning means such as a GPS receiver, and when displaying a map or a guide route, the current position mark indicating the current position and the direction mark indicating the traveling direction are superimposed and displayed to the user. Inform location and direction of travel. In addition, guidance points such as intersections are set in the guide route data, and voice guidance data (for example, a voice message such as “This is a 300m intersection, please turn left”) is added as guidance at the guidance points. In this case, a voice message is reproduced and output through a speaker to guide the user.

  In general, a navigation device mounted on a vehicle and dedicated to search for a moving route for the vehicle has a high processing capacity of a processor and a large capacity of a storage device that accumulates map data and road data for route search. Accordingly, a large amount of map data for three-dimensional display can be stored as in Patent Document 4, and three-dimensional display can be performed.

  On the other hand, in a communication-type navigation system in which a mobile terminal device such as a mobile phone is used as a terminal device of the navigation system, the processing capacity of the processor constituting the terminal device is not as high as that of a vehicle-mounted navigation device, and a storage device The storage capacity is small. The processor and the storage device are used not only for the navigation function but also for executing other functions of the terminal device. For example, when a mobile phone is used as a terminal device, the processor is also used to execute a call function that is an original function of the mobile phone.

  Even in the communication type navigation system, there is a voice requesting a realistic video expression including a three-dimensional display of a building. However, as a common problem of the communication type navigation, there is a problem of how to reduce the amount of communication data. Conventionally, emphasis has been placed on communication costs of terminal devices, but cost issues related to the increase in communication data are being solved by rate plans such as a flat rate system. However, if the amount of communication data is large, there is a problem of traffic load, and if the number of users increases, it becomes a more serious problem.

  However, when a map is three-dimensionally displayed, there is a problem that the amount of data is overwhelmingly larger than that of a flat map, which causes a problem that communication traffic increases and the server becomes excessive. For example, even if a 3D polygon is prepared using a building as a simple rectangular parallelepiped, the data amount is at least 6 times (six sides) compared to a plane polygon, and if the texture is attached to the drawing of the wall surface, the data amount is Increase significantly. This is a problem that goes against the suppression of the amount of communication data, and is an obstacle to stereoscopic display in communication navigation.

  The inventor of the present application has conducted various studies to solve the above problems, and as a result, when the terminal device displays a three-dimensional map of a building including a building, the three-dimensional polygon data constitutes an object such as a building. Focusing on the fact that it is composed of data on each surface, we came up with the idea that stereoscopic display is possible on the terminal side as long as there is polygon data on the surface that can be viewed from the viewpoint (position of the user) of the terminal device. Thus, the present invention has been completed.

  That is, the present invention aims to solve the above-mentioned problems, and in a communication-type navigation system including a terminal device and a route search server, when displaying a map three-dimensionally, from the route search server, An object of the present invention is to provide a navigation system, a route search server, a terminal device, and a map display method capable of distributing only polygon data necessary for display and suppressing the amount of communication data.

In order to solve the above-mentioned problem, the invention according to claim 1 of the present application is
Display means for displaying a three-dimensional map, a polygon database storing each object as polygon data for each surface constituting the object, and a polygon for selecting the surface of each object visible from the viewpoint position A navigation system comprising selection means, viewpoint position setting means for setting a viewpoint position , search network data for route search, and route search means ,
The viewpoint position setting means sets a predetermined position on the guide route searched by the route search means as a viewpoint position, and based on the viewpoint position set by the viewpoint position setting means, the polygon selection means determines a predetermined position from the viewpoint position. A plane of each object that can be seen from the viewpoint position with respect to polygon data within the range, and the selected plane is stored in the polygon database in association with a link in which the viewpoint position is set, and guide route search means The polygon data of the surface associated with the link is read from the polygon database on the basis of each link constituting the guide route searched for, and the display means displays a map based on the polygon data of the surface read from the polygon database. It is characterized by three-dimensional display.

The invention according to claim 2 of the present application is the invention according to claim 1,
The polygon data for each surface includes a normal vector indicating the surface direction, and the polygon selection unit generates a vector for viewing each surface of the object from the viewpoint position, and the vector, the normal vector, Is calculated, and a surface having the calculated angle of 90 ° or less is selected.

The invention according to claim 3 of the present application is the invention according to claim 1 ,
The viewpoint position setting means sets the positions of at least both ends of each link constituting the guide route searched by the route search means as viewpoint positions.

The invention according to claim 4 of the present application is the invention according to claim 3 ,
The polygon selecting unit generates a vector for viewing each surface of the object from the viewpoint position set on the guide route by the viewpoint position setting unit, and an angle formed between the vector and the link of the guide route at the viewpoint position is predetermined. When the angle is equal to or smaller than the value, an angle formed by a vector that anticipates each surface of the object and the normal vector is calculated, and a surface having the calculated angle of 90 ° or less is selected.

The invention according to claim 5 of the present application is
A route search server connected via a network to a terminal device having a display means for displaying a three-dimensional map based on polygon data distributed from the route search server,
The path search server includes a polygon database that stores each object as polygon data for each surface constituting the object, a polygon selection unit that selects a surface of each object visible from the viewpoint position, and a viewpoint. Viewpoint position setting means for setting a position , network data for search for route search, and route search means ,
The viewpoint position setting means sets a predetermined position on the guide route searched by the route search means as a viewpoint position, and based on the viewpoint position set by the viewpoint position setting means, the polygon selection means determines a predetermined position from the viewpoint position. A plane of each object that can be seen from the viewpoint position with respect to polygon data within the range, and the selected plane is stored in the polygon database in association with a link in which the viewpoint position is set, and guide route search means The polygon data of the surface associated with the link is read from the polygon database based on each link constituting the guide route searched by the polygon, and the polygon data of the surface selected by the polygon selecting means is used as the three-dimensional map display data. It is distributed to a terminal device.

The invention according to claim 6 of the present application is the invention according to claim 5 ,
The polygon data for each surface includes a normal vector indicating the surface direction, and the polygon selection unit generates a vector for viewing each surface of the object from the viewpoint position, and the vector, the normal vector, Is calculated, and a surface having the calculated angle of 90 ° or less is selected.

The invention according to claim 7 of the present application is the invention according to claim 5 ,
The viewpoint position setting means sets the positions of at least both ends of each link constituting the guide route searched by the route search means as viewpoint positions.

The invention according to claim 8 of the present application is the invention according to claim 7 ,
The polygon selecting unit generates a vector for viewing each surface of the object from the viewpoint position set on the guide route by the viewpoint position setting unit, and an angle formed between the vector and the link of the guide route at the viewpoint position is predetermined. When the angle is equal to or smaller than the value, an angle formed by a vector that anticipates each surface of the object and the normal vector is calculated, and a surface having the calculated angle of 90 ° or less is selected.

The invention according to claim 9 of the present application is
A polygon database in which each object is stored as polygon data for each surface constituting the object for 3D display, polygon selection means for selecting the surface of each object visible from the viewpoint position, and a viewpoint position for setting the viewpoint position Setting means, search network data for route search, and route search means , wherein the viewpoint position setting means uses a predetermined position of the guide route searched by the route search means as a viewpoint position, and the viewpoint Based on the viewpoint position set by the position setting means, the polygon selection means selects each object surface visible from the viewpoint position for polygon data within a predetermined range from the viewpoint position, and the selected surface is It is stored in the polygon database in association with the link where the viewpoint position is set, and the guide route search means searches for it. Terminals based on each link, reads the polygon data of the surface associated with the link from the polygon database are connected via a network to a route search server for distributing polygon data of the selected surfaces constituting the the guide route A device,
Is the terminal device and display means for displaying three-dimensional map based on the polygon data received from the route search server, a viewpoint detector for detecting a viewpoint position, with a view point position where the viewpoint position detecting means detects Information is transmitted to the route search server, and the map is three-dimensionally displayed on the display means based on the polygon data of the surface received from the route search server.

The invention according to claim 10 of the present application is
Display means for displaying a three-dimensional map, a polygon database storing each object as polygon data for each surface constituting the object, and a polygon for selecting the surface of each object visible from the viewpoint position A map display method in a navigation system comprising: selection means; viewpoint position setting means for setting a viewpoint position ; search network data for route search; and route search means ,
The map display method is:
The viewpoint position setting means sets the viewpoint position to a predetermined position of the guide route searched by the route search means, and the polygon selection means sets the viewpoint position based on the viewpoint position set by the viewpoint position setting means. Selecting a surface of each object that can be seen from the viewpoint position for polygon data within a predetermined range, and storing the selected surface in the polygon database in association with a link in which the viewpoint position is set Reading the polygon data of the surface associated with the link from the polygon database based on each link constituting the guide route searched by the guide route searching means, and the display means reading from the polygon database. Yusuke and displaying three-dimensional map based on the polygon data of the surface, the It is characterized in.

The invention according to claim 11 of the present application is the invention according to claim 10 ,
The polygon data for each surface includes a normal vector indicating the surface direction, and the first step generates a vector for the polygon selection means to predict each surface of the object from the viewpoint position. And the normal vector, and a process of selecting a surface having the calculated angle of 90 ° or less is included.

The invention according to claim 12 of the present application is the invention according to claim 10 ,
The step in which the viewpoint position setting means sets the predetermined position of the guide route searched by the route search means as the viewpoint position includes the step of setting the viewpoint position of each link constituting the guide route searched by the route search means. It includes a process of setting at least the positions of both ends as viewpoint positions.

The invention according to claim 13 of the present application is the invention according to claim 12 ,
In the first step, the polygon selection unit generates a vector for viewing each surface of the object from the viewpoint position set on the guidance route by the viewpoint position setting unit, and the vector and the guidance route at the viewpoint position are generated. Including a process of calculating an angle formed between a vector that anticipates each surface of the object and the normal vector when an angle formed with the link is equal to or less than a predetermined value, and selecting a surface with the calculated angle of 90 ° or less. It is characterized by.

In the invention according to claim 1, the navigation system includes display means for displaying a three-dimensional map, a polygon database storing each object as polygon data for each surface constituting the object for the three-dimensional display, A polygon selection means for selecting the surface of each object visible from the viewpoint position, a viewpoint position setting means for setting the viewpoint position , search network data for route search, and a route search means. Yes. The viewpoint position setting means sets a predetermined position on the guide route searched by the route search means as a viewpoint position, and based on the viewpoint position set by the viewpoint position setting means, the polygon selection means is within a predetermined range from the viewpoint position. The surface of each object that can be seen from the viewpoint position is selected for the polygon data of the object, the selected surface is stored in the polygon database in association with the link for which the viewpoint position is set, and searched by the guide route search means Based on each link constituting the guide route, the polygon data of the surface associated with the link is read from the polygon database, and the display means displays the map three-dimensionally based on the polygon data of the surface read from the polygon database .

According to such a configuration, a route search to the destination is performed, a viewpoint position is set in the guide route obtained as a result of the route search, an object surface visible from the viewpoint position is selected, and a polygon on this surface is selected. Since the map can be three-dimensionally displayed based on the data, the amount of communication data between the display means and the means for distributing the display data can be suppressed. In addition, since the link of the guide route and the surface of each object visible from the viewpoint position set to the link are associated and accumulated in the polygon gater base, the viewpoint position setting means sets the viewpoint position each time the route is searched. Further, it is possible to eliminate the need for the polygon selection means to calculate, and the processing capacity of the navigation system can be improved.

  In the invention according to claim 2, in the invention according to claim 1, the polygon data for each surface includes a normal vector indicating the surface direction, and the polygon selection means A vector for generating a surface is generated, an angle formed by the vector and the normal vector is calculated, and a surface having the calculated angle of 90 ° or less is selected.

  According to such a configuration, only the surface of the object visible from the viewpoint position can be easily selected, and the map can be three-dimensionally displayed based on the polygon data of this surface.

In the invention according to claim 3 , in the invention according to claim 1 , the viewpoint position setting means sets the positions of at least both ends of each link constituting the guide route searched by the route search means as the viewpoint positions.

  According to such a configuration, a viewpoint is set for each link of the guide route, only the surface of the object visible from the viewpoint position is selected, and a map along the guide route is three-dimensionally displayed based on the polygon data of this surface. Will be able to.

In the invention according to claim 4 , in the invention according to claim 3 , the polygon selection unit generates a vector for predicting each surface of the object from the viewpoint position set on the guide route by the viewpoint position setting unit, When the angle formed between the vector and the guide route link at the viewpoint position is less than or equal to a predetermined value, the angle formed between the vector that looks into each surface of the object and the normal vector is calculated, and the calculated angle is 90 ° or less. Select the face.

  According to such a configuration, the polygon selection unit generates a vector for estimating each surface of the object from the viewpoint position, and the angle formed by the vector and the guide route link at the viewpoint position is equal to or smaller than a predetermined value. Since the angle formed by the normal vector and the vector that anticipates each surface of the object is calculated, the frequency of the arithmetic processing in the polygon selection means can be reduced.

In the invention according to claims 5 to 8 , it is possible to provide a route search server constituting the navigation system according to claims 1 to 4 , respectively. In the invention according to claim 9 , the invention is claimed. The terminal device according to item 1 can be provided. In the inventions according to claims 10 to 13 , it is possible to provide a map display method in the navigation system according to claims 1 to 4 , respectively.

  Hereinafter, specific examples of the present invention will be described in detail with reference to examples and drawings. In the following embodiments, a specific example is a navigation system that uses a mobile phone as a terminal device and can selectively use a display mode for displaying a map or the like in a two-dimensional display or a bird's eye view and a display mode in a three-dimensional display. However, the present invention is not limited to such an embodiment, and the terminal device may be a mobile terminal such as a vehicle-mounted terminal device. In this specification, the term “terminal device” including a mobile terminal is generically referred to.

  FIG. 1 is a block diagram showing a configuration of a navigation system according to an embodiment of the present invention. As shown in FIG. 1, the navigation system 10 includes a terminal device 20 and a route search server 30 connected via a network 12 such as the Internet. The route search server 30 includes route search means 316, search network data 317, a map database 315 storing map data, and a polygon database 318 storing three-dimensional polygons of roads and buildings.

  If there is a route search request from the terminal device 20 including a route search condition such as the current position, destination, moving means (automobile, walking, transportation or combined use of walking and transportation), the search network data 317 is referred to. A plurality of guide routes are searched in order of the shortest guide route or route length that matches the route search condition. Guide route data obtained as a result of the search is obtained from a plurality of unit map data (map data divided into areas of a predetermined size by latitude and longitude) including the current position selected from the map database 315 and from the polygon database 318. The data is distributed to the terminal device 20 together with the three-dimensional polygon data of the roads and buildings on the selected unit map data.

  The search network data 317 includes road network data 317A and traffic network data 317B, and can search for routes using walking, automobiles, or transportation. The road network data 317A and the traffic network data 317B are network data based on a normal plane map having no node altitude information. Therefore, the guidance route data searched by the route search means 316 is planar route data and does not have altitude information.

  When receiving the guidance route from the route search server 30 to the destination, the terminal device 20 displays a map near the current position on the display means. On the map image displayed on the display means, a guidance route and a current position mark indicating the current position are displayed superimposed. In general, a unit map of a predetermined size is displayed with the current position mark at the center of the display screen. When three-dimensional stereoscopic map display is performed, three-dimensional polygon data of roads and buildings around the current position are received from the route search server 30 and displayed.

  As will be described later, the three-dimensional polygon data is data of each surface constituting an object such as a building. In the present invention, the terminal device 20 transmits viewpoint position information including the viewpoint position in the terminal device 20 and the direction of the line of sight to the route search server 30 by the viewpoint position detection means. Based on the viewpoint position information received from the terminal device 20, the route search server 30 selects only polygon data corresponding to the surface visible from the terminal device 20 and distributes it to the terminal device by a method described later.

  The terminal device 20 displays a three-dimensional map and a building image on the display unit based on the three-dimensional polygon data received from the route search server. As a result, the polygon data transmitted / received between the route search server 30 and the terminal device 20 is only the polygon data of the surface that can be viewed from the viewpoint position according to the viewpoint position of the terminal device 20, so It will be possible to do with the amount of data.

  The route search server 30 also includes control means 311, communication means 312, distribution data editing means 313, guide route data creation means 314, polygon selection means 319, and viewpoint position setting means 320. Although not shown, the control unit 311 is a microprocessor having a RAM, a ROM, and a processor, and controls the operation of each unit by a control program stored in the ROM. The communication unit 312 is an interface for communicating with the terminal device 20 via the network 12. The guide route data creation means 314 creates guide route data, map data, guidance points, guidance data at guidance points, and the like searched as described above, and the distribution data editing means 313 stores the data such as the guide routes. Edit the data to be distributed to the device 20.

  The polygon selection means 319 uses the viewpoint position information received from the terminal device 20 or the information on the predetermined viewpoint position set by the viewpoint position setting means 320 based on the three-dimensional polygon data stored in the polygon database 318 by a method described later. Then, only polygon data corresponding to the surface visible from the terminal device 20 is selected and distributed to the terminal device.

  The road network data 317A is configured as follows. For example, when the road is composed of roads A, B, and C as shown in FIG. 2, the end points, intersections, and inflection points of the roads A, B, and C are used as nodes, and the roads connecting the nodes are directed links. Link cost data with node data (node latitude / longitude), link data (link number) and link cost of each link (link distance or time required to travel the link) as data Composed.

  That is, in FIG. 2, Nn (◯ mark) and Nm (◎ mark) indicate nodes, and Nm (◎ mark) indicates a road intersection. Directional links connecting the nodes are indicated by arrow lines (solid line, dotted line, two-dot chain line). As for the links, there are links facing in the upward and downward directions of the road, but in FIG. 2, only the links in the direction of the arrows are shown for the sake of simplicity.

  When route search is performed using such road network data as a route search database, links linked from the starting node to the destination node are traced to accumulate the link cost, thereby minimizing the accumulated link cost. Search and guide the route. That is, in FIG. 2, when a route search is performed with the departure point as the node AX and the destination as the node CY, the road travels from the node AX to the road A, turns right at the second intersection, enters the road C, and reaches the node CY. The link cost is accumulated sequentially, and a route that minimizes the accumulated link cost is searched for and guided.

  Although other routes from the node AX to the node CY are not shown in FIG. 2, there are actually other such routes, so that a plurality of routes that can be reached from the node AX to the node CY are displayed. A search is performed in the same manner, and a route with the lowest link cost is determined as the optimum route. This method is performed by, for example, a known method called the Dijkstra method.

  The data of the traffic network data 317B is basically the same as the road network data, but the network data assumes that each train operating on the route constitutes a link between stations (a link between each station is a node and a station). Has been created. Therefore, the guide route is a link specifying a train that is a link. In order to search for a route from a certain departure point to a certain destination using such traffic network data, all the means of transportation that can be used (ride) when arriving from the departure point to the destination are searched. A guide route is specified by specifying a means of transportation that matches the search conditions.

  On the other hand, the terminal device 20 is a mobile phone equipped with a GPS positioning unit 212 such as a GPS receiver, and includes a control unit 211, a GPS positioning unit 212, a display mode control unit 213, a viewpoint position detection unit 214, and a two-dimensional display. A control unit 215, a three-dimensional display control unit 216, a communication unit 217, a distribution request editing unit 218, a distribution data storage unit 219, a VRAM 220, a display unit 221, an operation / input unit 222, and the like are configured. Users can select walking or transportation as a means of transportation and receive route guidance using walking or transportation, and when they are in the passenger seat of a car, they can select a car as the means of transportation and get directions. Can receive.

  Although not shown, the control unit 211 includes a microprocessor (CPU) having a RAM and a ROM, and controls the operation of each unit by a control program stored in the ROM. The operation / input means 222 is for operation / input means consisting of numeric keys, alphabet keys, other function keys, selection keys, scroll keys, and the like. From the menu screen displayed on the display means 221 as output means Various input operations are performed by selecting a desired menu or operating keys. Accordingly, the display unit 221 also functions as a part of the operation / input unit 222. The communication unit 217 is an interface for communicating with the route search server 30 via the network 12.

  When a user wants to request a route search from the route search server 30, the user operates the operation / input unit 222 on the terminal device 20, selects a route search from the service menu displayed on the display unit 221, Enter route search conditions such as location, means of transportation (car, walking, transportation, or a combination of walking and transportation). The route search condition is edited into a distribution request to the route search server 30 by the distribution request editing unit 218 and transmitted to the route search server 30 via the communication unit 217.

  Distribution data from the route search server 30 is temporarily stored in the distribution data storage unit 219, read out from the distribution data storage unit 219 as necessary, and displayed on the display unit 221. The terminal device 20 performs a first display mode (hereinafter referred to as a two-dimensional display mode) for two-dimensional display or bird's-eye view display of a map, guide route, building image, and the like included in the distribution data, and three-dimensional display for three-dimensional display. A second display mode (hereinafter referred to as a three-dimensional display mode), and the display mode control means 213 selectively operates one of the two-dimensional display control means 215 and the three-dimensional display control means 216. Display on the display means 221 is performed. The user designates a desired display mode using the operation / input means 222.

  The two-dimensional display control means 215 performs control to display them as a two-dimensional image (planar image) using plane data such as a map, road, guide route, and building delivered from the route search server 30. When displaying a bird's-eye view, the two-dimensional display control means 215 performs control to create and display a bird's-eye view image of a two-dimensional map or road viewed from a predetermined viewpoint position. The three-dimensional display control means 216 performs control to process and display a three-dimensional image using three-dimensional polygon data such as maps, roads, and buildings distributed from the route search server 30. The image data created by the two-dimensional display control means 215 and the three-dimensional display control means 216 is developed in dot units in the VRAM 220 that is a drawing means, and an image in a desired display mode is displayed on the display means 221.

  The GPS positioning means 212 periodically measures the current position of the terminal device 20 and acquires the current position (latitude / longitude). A current position mark indicating the current position measured by the GPS positioning means 212 is displayed superimposed on an image such as a map or a guide route displayed on the display means 221.

  Next, a method for selecting polygon data for three-dimensional display according to the present invention will be described. Prior to that, a three-dimensional polygon for roads and buildings for three-dimensional display will be described. When the road RD1 is viewed three-dimensionally, the road is composed of a continuous body having different slopes. That is, as shown in FIG. 3, the road RD1 has surfaces (a) to (d) with different inclinations. The three-dimensional polygon of the road includes the shape data of each of the continuous surfaces (a) to (d), the position data (position coordinates) of each vertex, and a normal vector (in FIG. 3) indicating the direction of each surface. Each arrow). Therefore, if the surface image data is generated according to the surface shape data and each surface is arranged along the direction calculated based on the normal vector, a three-dimensional road image as shown in FIG. 3 is displayed. Can do.

  Here, the orientation of each surface can be calculated by arranging the coordinates of each vertex of the surface according to a certain rule, even if the normal vector is not included in the polygon data. For example, if the rules are such that the respective coordinate points are arranged counterclockwise when viewed from the front side, the orientation of the surface can be calculated without having a normal vector.

  The same applies to the three-dimensional polygons of buildings. The building is broken down into its constituent faces, and each shape data, position data (position coordinates) of each vertex, and a normal vector indicating the orientation of each face It can be expressed by the normal vector which direction each face of the building is facing. Using such polygons, image data is generated by performing hidden surface processing by a well-known Z buffer method. Hidden surface processing refers to processing for erasing a surface that is not visible from the direction of the line of sight, thereby displaying a three-dimensional image of the building.

  For example, a building polygon is made up of graphic data of surfaces constituting the building as shown in FIG. In FIG. 4, a building A is composed of graphic data of surfaces such as surfaces SA1, SA2, and SA3, and has a normal vector indicating the direction of each surface. For example, the surface SA1 of the building A has a normal vector A1. In FIG. 4, the back side surface of the building is not visible, but polygon data of the back side surfaces SA4, SA5, and SA6 are prepared in the same manner. For example, the surface on the back side of the surface SA1 is the surface SA4, and has a normal vector A4 that is opposite to the normal vector A1 of the surface SA1. Note that FIG. 4 is drawn for explaining the positional relationship between the spaces, and is not a screen displayed on the terminal device 20.

  The same applies to the building B, which is composed of graphic data of the surfaces SB1 to SB6 and has a normal vector indicating the direction of each surface. When the surface of each building is viewed from the viewpoint position P of FIG. 4 in such a polygon figure, the surface in which the surface can be seen from the viewpoint position from the vector that expects the surface of interest from the viewpoint position and the normal vector of the surface. And whether or not the surface is facing.

  For example, assuming that the surface of interest from the viewpoint position P is the surface SA1 of the building A, a vector VA1 that looks into the surface SA1 from the viewpoint position P is taken. If the angle θA1 formed by the vector VA1 and the normal vector A1 (the inner product of both vectors is less than a right angle) is less than a right angle, it can be seen that the surface of this surface faces the viewing direction. Therefore, it can be seen that this surface is a surface displayed on the display means. If the angle formed by both vectors is not less than a right angle, such as the vector VB1 and the normal vector B1, it can be seen that the surface is not visible from the viewpoint position, and this surface is not displayed on the display means. In FIG. 4, E is the height of the viewpoint position, and is the average eye height (about 1.5 m) when a pedestrian is using the terminal device.

  As described above, when the terminal device 20 performs three-dimensional display, not all polygon data is required, and only polygon data of a surface visible from the viewpoint position is sufficient. Therefore, in the present invention, when the terminal device 20 performs three-dimensional display, viewpoint information is transmitted from the terminal device 20 to the route search server 30, and the route search server 30 determines a surface necessary for display based on the viewpoint information. The polygon data is selected and distributed to the terminal device 20. In the terminal device 20, based on the received polygon data of the surface, an image actually viewed from the viewpoint is drawn using a known Z buffer method or the like.

  For this reason, the terminal device 20 detects the viewpoint position and the line-of-sight direction by the viewpoint position detection unit 214 and transmits it to the route search server 30 as viewpoint information. The viewpoint position is generally the current position (latitude / longitude) measured by the GPS positioning means 212, and the line-of-sight direction is the traveling direction of the terminal device 20, but in the route guidance by the navigation system, it is the moving direction on the guidance route. is there.

  On the other hand, the route search server 30 is provided with polygon selection means 319. When the route search server 30 receives the viewpoint information from the terminal device 20, the route search server 30 reads three-dimensional polygon data in a predetermined range around the viewpoint position from the polygon database 318, As described in FIG. 4, the selection unit 319 creates a vector that anticipates each surface of the building that is the object from the viewpoint position, calculates an angle formed with the normal vector that each surface has, and an angle formed by both vectors Selects a surface having a right angle or less, and distributes polygon data of the surface to the terminal device 20.

  Even if the polygon data does not have a normal vector, if the coordinate data of the vertexes of the surface is recorded in the counterclockwise direction as described above, the surface faces from the coordinates of each vertex. The direction visible from the viewpoint position can be selected from the relationship between the viewpoint position and the line-of-sight direction.

  Here, when the terminal device 20 moves on the guide route and the viewpoint position changes, the terminal device 20 may transmit the viewpoint position information to the server again at an appropriate interval and newly receive the plane data. Since the terminal device has a unique ID and is communicatively connected to the route search server 30, the route search server 30 recognizes the ID and sends only surface data not transmitted to the terminal device 20. You can also.

  In addition to the above method, the terminal device 20 requests the route search server 30 to search for a route, and along with the guidance route data obtained by the route search server 30 searching for the route, polygon data for three-dimensional display is provided to the terminal device 20. You can also take the method of delivering to. An example will be described below.

  FIG. 5 is a diagram illustrating the relationship between the guide route RT, the viewpoint position, and the surface of the building. As shown in FIG. 5, when the guide route RT obtained by searching in the route search server 30 is the link LKn and the link LKn + 1, the viewpoints Pn−1, Pn, and Pn + 1 are set on the end points (nodes) of each link. . If the link is long, a viewpoint is set also in the middle of the link, and a predetermined range around the route is targeted without omission. The viewpoint position setting unit 320 performs such setting of the viewpoint position. In the above-described case where the viewpoint position information is received from the terminal device 20, the viewpoint position setting unit 320 determines the viewpoint position based on the viewpoint position information received from the terminal device 20.

  FIG. 6 is a diagram schematically showing this state, and the viewpoint position Pn0 is set in the middle of the link LKn. In FIG. 6, a circle centered at each viewpoint position Pn−1, Pn, Pn0, Pn + 1 schematically shows an area where 3D polygon data is distributed. When the link is long, even if the viewpoint position is set only at the end point, if the area where the three-dimensional polygon can be obtained is interrupted, the display in between will be skipped. However, by setting the viewpoint position Pn0 in the middle of the link, this Can be prevented. For this reason, the interval for setting the viewpoint position in the middle of the link is preferably determined by the radius of the area from which the three-dimensional polygon is extracted. In this case, the terminal device 20 may transmit the current position to the route search server 30, and the route search server 30 distributes the plane data at the viewpoint position based on the current position.

  At each of these viewpoint positions Pn−1, Pn, Pn0, and Pn + 1, only the polygon of the surface that can be seen at each viewpoint position is selected by the method described above, and distributed to the terminal device 20 together with the guidance route data. The polygon data may be transmitted together with all the guidance route data, or only the guidance route data is distributed, and the polygon data is moved to the viewpoint position as the terminal device 20 moves on the guidance route. Each time it reaches, it may be divided and distributed.

  In addition, when a guidance route is obtained, it is assumed that the route travels along the guidance route. Therefore, the surface may be extracted by limiting the direction of the line of sight to the traveling direction of the guidance route at the viewpoint position. FIG. 7 is a schematic diagram showing this concept. As shown in FIG. 7, the calculation is continued only when the vector VB1 that looks at the target surface from the viewpoint position Pn−1 is within a predetermined angle range with respect to the path, and the normal vector B1 of the surface and the vector VB1 It is determined whether or not the angle formed by is less than a right angle. In FIG. 7, the calculation is performed when the angle αB1 is less than a right angle. If a narrower field of view is assumed, the determination angle may be narrowed. By doing so, it is possible to further reduce the surface data to be transmitted.

  In the method of selecting polygon data for three-dimensional display together with the guide route described with reference to FIGS. 5 and 7 and delivering it to the terminal device 20, the terminal device 20 sends viewpoint position information to the route search server 30. The transmission method or the method in which the route search server 30 calculates the viewpoint position based on the current position information from the terminal device 20 after the terminal device 20 issues a route search request to the route search server 30. The search server 30 needs to perform the above calculation for each viewpoint position every time the surface polygon is distributed.

  Therefore, when the link for setting the viewpoint position is stored in association with the polygon of the surface visible from the viewpoint position, when the link of the road (link of the guide route) is distributed, the associated surface is stored. These polygons may be combined and distributed from the route search server 30. In this case as well, general roads can pass in both directions, so it is possible to calculate and select the surface that can be seen around the entire circumference for bidirectional links, and on one-way roads, it seems to be limited to the permitted direction of travel. You may make it select a surface by calculating.

  If comprised in this way, since the route search server 30 does not need to calculate the surface which can be seen from a viewpoint position each time, since a result can be immediately delivered with respect to the request | requirement from the terminal device 20, a route search with the terminal device 20 is possible. The network session with the server 30 is not held for a long time. Therefore, the processing capability of the route search server 30 can be improved.

  As described above in detail, according to the present invention, when a three-dimensional map image is displayed, a plane necessary for display can be obtained from the polygons accumulated by the route search server 30 for three-dimensional display. It can be selected and distributed to the terminal device 20, and the network load for communication can be reduced.

  The present invention is most effective in a communication-type navigation system including the terminal device 20 and the route search server 30. By storing polygons necessary for three-dimensional map display in association with road links. Therefore, it is possible to reduce the processing load, and it is effective for speeding up a navigation apparatus that operates stand-alone.

It is a block diagram which shows the structure of the navigation system concerning the Example of this invention. It is a schematic diagram which shows the concept of the road network data for a route search. It is a schematic diagram for demonstrating the structure of a road polygon. It is a schematic diagram for demonstrating the relationship between the structure of a building polygon, and a viewpoint position. It is a figure which shows the relationship between a guidance route | route, a viewpoint position, and the surface of a building. It is a schematic diagram which shows the concept which sets a viewpoint position in the middle of the link of a guidance route. It is a schematic diagram which shows the concept of the surface polygon selection when a viewpoint position is set to the guide route and the line-of-sight direction is the traveling direction of the guide route.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Navigation system 12 ... Network 20 ... Terminal device 211 ... Control means 212 ... GPS positioning means 213 ... Display mode control means 214 ... Viewpoint position detection means 215 ... 2D display control means 216 ... 3D display control means 217 ... Communication means 218 ... Distribution request editing means 219 ... Distribution data storage means 220 ... VRAM
221 ... Display means 222 ... Operation / input means 30 ... Route search server 311 ... Control means 312 ... Communication means 313 ... Distribution data editing means 314 ... Guide route data creation Means 315 ... Map database 316 ... Route search means 317 ... Search network data 317A ... Road network data 317B ... Traffic network data 318 ... Polygon database 319 ... Polygon selection means 320 ... Viewpoint position setting means

Claims (13)

Display means for displaying a three-dimensional map, a polygon database storing each object as polygon data for each surface constituting the object, and a polygon for selecting the surface of each object visible from the viewpoint position A navigation system comprising selection means, viewpoint position setting means for setting a viewpoint position , search network data for route search, and route search means ,
The viewpoint position setting means sets a predetermined position on the guide route searched by the route search means as a viewpoint position, and based on the viewpoint position set by the viewpoint position setting means, the polygon selection means determines a predetermined position from the viewpoint position. A plane of each object that can be seen from the viewpoint position with respect to polygon data within the range, and the selected plane is stored in the polygon database in association with a link in which the viewpoint position is set, and guide route search means The polygon data of the surface associated with the link is read from the polygon database on the basis of each link constituting the guide route searched for, and the display means displays a map based on the polygon data of the surface read from the polygon database. A navigation system characterized by three-dimensional display.   The polygon data for each surface includes a normal vector indicating the surface direction, and the polygon selection unit generates a vector for viewing each surface of the object from the viewpoint position, and the vector, the normal vector, 2. The navigation system according to claim 1, wherein an angle formed by the first angle is calculated, and a plane whose calculated angle is 90 ° or less is selected. The navigation system according to claim 1 , wherein the viewpoint position setting means sets the positions of at least both ends of each link constituting the guide route searched by the route search means as viewpoint positions. The polygon selecting unit generates a vector for viewing each surface of the object from the viewpoint position set on the guide route by the viewpoint position setting unit, and an angle formed between the vector and the link of the guide route at the viewpoint position is predetermined. If the value below to calculate the vector to allow for each surface normal vector and the angle of the object, the calculated angle according to claim 3, characterized by selecting the following aspects 90 ° Navigation system. A route search server connected via a network to a terminal device having display means for displaying a three-dimensional map based on polygon data distributed from the route search server,
The path search server includes a polygon database that stores each object as polygon data for each surface constituting the object, a polygon selection unit that selects a surface of each object visible from the viewpoint position, and a viewpoint. Viewpoint position setting means for setting a position , network data for search for route search, and route search means ,
The viewpoint position setting means sets a predetermined position on the guide route searched by the route search means as a viewpoint position, and based on the viewpoint position set by the viewpoint position setting means, the polygon selection means determines a predetermined position from the viewpoint position. A plane of each object that can be seen from the viewpoint position with respect to polygon data within a range of, and the selected plane is stored in the polygon database in association with a link for which the viewpoint position is set. The polygon data of the surface associated with the link is read from the polygon database based on each link constituting the guide route searched by the polygon, and the polygon data of the surface selected by the polygon selection means is used as the three-dimensional map display data. A route search server that is distributed to a terminal device. The polygon data for each surface includes a normal vector indicating the surface direction, and the polygon selection unit generates a vector for viewing each surface of the object from the viewpoint position, and the vector, the normal vector, The route search server according to claim 5 , wherein an angle formed by the angle is calculated, and a surface having the calculated angle of 90 ° or less is selected. 6. The route search server according to claim 5 , wherein the viewpoint position setting means sets the positions of at least both ends of each link constituting the guide route searched by the route search means as viewpoint positions. The polygon selecting unit generates a vector for viewing each surface of the object from the viewpoint position set on the guide route by the viewpoint position setting unit, and an angle formed between the vector and the link of the guide route at the viewpoint position is predetermined. If the value below to calculate the vector to allow for each surface normal vector and the angle formed by the object, the calculated angle according to claim 7, characterized by selecting the following aspects 90 ° Route search server. A polygon database in which each object is stored as polygon data for each surface constituting the object for 3D display, polygon selection means for selecting the surface of each object visible from the viewpoint position, and a viewpoint position for setting the viewpoint position Setting means, search network data for route search, and route search means , wherein the viewpoint position setting means uses a predetermined position of the guide route searched by the route search means as a viewpoint position, and the viewpoint Based on the viewpoint position set by the position setting means, the polygon selection means selects each object surface visible from the viewpoint position for polygon data within a predetermined range from the viewpoint position, and the selected surface is It is stored in the polygon database in association with the link where the viewpoint position is set, and the guide route search means searches for it. Terminals based on each link, reads the polygon data of the surface associated with the link from the polygon database are connected via a network to a route search server for distributing polygon data of the selected surfaces constituting the the guide route A device,
It is the terminal device and display means for displaying three-dimensional map based on the polygon data received from the route search server, and the viewpoint position detecting means for detecting a viewpoint position, with a view point position where the viewpoint position detecting means detects A terminal device that transmits information to the route search server and three-dimensionally displays a map on the display means based on polygon data of a surface received from the route search server. Display means for displaying a three-dimensional map, a polygon database storing each object as polygon data for each surface constituting the object, and a polygon for selecting the surface of each object visible from the viewpoint position A map display method in a navigation system comprising selection means, viewpoint position setting means for setting a viewpoint position , search network data for route search, and route search means ,
The map display method is:
The viewpoint position setting means sets the viewpoint position to a predetermined position of the guide route searched by the route search means, and the polygon selection means sets the viewpoint position based on the viewpoint position set by the viewpoint position setting means. Selecting a surface of each object that can be seen from the viewpoint position for polygon data within a predetermined range, and storing the selected surface in the polygon database in association with a link in which the viewpoint position is set Reading the polygon data of the surface associated with the link from the polygon database based on each link constituting the guide route searched by the guide route searching means, and the display means reading from the polygon database. Yusuke and displaying three-dimensional map based on the polygon data of the surface, the Map display method, characterized in that. The polygon data for each surface includes a normal vector indicating the surface direction, and the first step generates a vector for the polygon selection means to predict each surface of the object from the viewpoint position. The map display method according to claim 10 , further comprising: processing for calculating an angle formed by the normal vector and selecting a surface having the calculated angle of 90 ° or less. The step in which the viewpoint position setting means sets the predetermined position of the guide route searched by the route search means as the viewpoint position includes the step of setting the viewpoint position of each link constituting the guide route searched by the route search means. The map display method according to claim 10 , comprising a process of setting at least the positions of both ends as viewpoint positions. In the first step, the polygon selection unit generates a vector for viewing each surface of the object from the viewpoint position set on the guidance route by the viewpoint position setting unit, and the vector and the guidance route at the viewpoint position are generated. Including a process of calculating an angle formed between a vector that anticipates each surface of the object and the normal vector when an angle formed with the link is equal to or less than a predetermined value, and selecting a surface with the calculated angle of 90 ° or less. The map display method according to claim 12 , wherein:

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