JP5652165B2 - Map data used for route search of route search device and route search device - Google Patents

Description

  The present invention relates to a route search device that searches for a route from a departure point to a destination, and map data used for route search of the route search device.

  2. Description of the Related Art In recent years, a navigation device is often mounted on a vehicle that provides vehicle travel guidance so that a driver can easily arrive at a desired destination. Here, the navigation device detects the current position of the vehicle with a GPS receiver or the like, acquires map data corresponding to the current position from a recording medium such as a DVD-ROM or HDD, and displays it on a liquid crystal monitor. It is a possible device. Then, map data including the current position of the vehicle is read from a recording medium or the like, a map image around the current position of the vehicle is drawn based on the map data and displayed on the display device, and the vehicle position mark is overlaid on the map image. You can also see at a glance which point the vehicle is currently driving by scrolling the map image as the vehicle moves, or by fixing the map image to the screen and moving the vehicle position mark I have to. In addition, the navigation device has a route search function for searching for an optimum route from a departure point (for example, the current position of the host vehicle) to the set destination when a desired destination is set. It also has a travel guidance function for guiding travel according to the route. In recent years, some cellular phones, PDAs (Personal Digital Assistants), personal computers, and the like have functions similar to those of the navigation device.

  Here, the map data stored in the navigation device or the like has a structure that is hierarchized into a plurality of layers based on the difference in the information amount of the road network. Furthermore, each layer is divided into a plurality of regions (regions) and stored. For example, Japanese Unexamined Patent Application Publication No. 2009-156940 describes that map data is hierarchized into three layers, layers 1 to 3, and map data is divided into a plurality of blocks and stored in each layer.

Japanese Patent Laying-Open No. 2009-156940 (5th page, FIG. 1)

  Here, when map data is divided into a plurality of regions as described above, in order to appropriately search for a route that runs near the boundary of the region, an overlap region that overlaps regions is generally provided. Yes. FIG. 10 shows an example of a region 200 that conventionally constitutes map data. As shown in FIG. 10, the region 200 includes a core region 201 and an overlap region 202 formed around the core region 201. As a result, as shown in FIG. 11, the overlap area 202 overlaps with the core area 201 of the other region 200 and the overlap area 202 of the other region 200, and the data size of the map data becomes larger than necessary. It was. In addition, since the number of links and nodes to be searched increases, the time required for the route search process increases, and the processing load increases.

  In addition, when map data is divided into a plurality of regions, a region to be searched is determined in advance based on the positional relationship between the departure point and the destination. However, if an overlap area is provided as in the prior art, a different route may be searched depending on the route search direction (departure → destination or destination → departure). In particular, when a search is performed from both a departure point and a destination by two CPUs, a different route is searched each time a search process is performed even if the departure point and the destination are the same, depending on the state of the CPU at the time of the search. There is a case.

  Hereinafter, the above problem will be described in more detail with reference to FIG. The example shown in FIG. 11 shows an example of searching for a route when a point X is set as a departure point, a point Y is set as a destination, and regions A and B are determined as search targets. Here, in the example shown in FIG. 11, the route connecting the point X and the point Y includes a “lower route” passing through a general road and an “upper route” passing through a toll road. Then, when searching from the starting point from the point X direction to the point Y direction, the node 203 to which the boundary node 202 of the “lower route” region A is connected becomes a node in the core region of the region B. Therefore, the “lower route” is a candidate for a route candidate. Further, since the node 205 to which the boundary node 204 of the region A of the “upper route” is connected is also a node in the core region of the region B, the “upper route” is also a candidate for the route. Therefore, when searching from the starting point X direction to the point Y direction, both “upper route” and “lower route” become route candidates, and either route is determined as a guide route based on the cost calculation result. Become.

  On the other hand, when a search is performed from the destination point Y direction to the point X direction, the node 211 to which the boundary node 210 of the region B of the “lower route” is connected becomes a node in the core region of the region A. Therefore, the “lower route” is a candidate for a route candidate. However, the node 213 to which the boundary node 212 of the “upper route” region B is connected is not a node in the core region of the region A (that is, a node in the core region of the region not to be searched). Therefore, the “upper route” is not a candidate for a route candidate (the route is not connected). Therefore, when searching from the destination point Y direction to the point X direction, only the “lower route” becomes a route candidate, which is different from the case of searching from the starting point point X direction to the point Y direction. A guide route may be set.

  The present invention was made in order to solve the above-described conventional problems, by reducing the data size of the map data by deleting the overlap area, reducing the processing time and processing load of the route search process, It is an object of the present invention to provide a route search device capable of performing an appropriate route search and map data used for the route search of the route search device.

In order to achieve the object, a route search device (1) according to claim 1 of the present application includes a map data storage medium (31) for storing map data (32), and the map data stored in the map data storage medium. And a route search device (51) for searching a route from the departure point to the destination based on the map data storage medium, the map data storage medium dividing the map data into a plurality of regions Stratified and stored in a plurality of layers based on the amount of information of the road network, and for each area of the map data, subordinate relation information in which a parent-child relationship with a higher layer area including the area is associated is stored. The map data of the specific layer among the plurality of layers is stored so that there is no overlapping area where the areas overlap, and the map data of the layers other than the specific layer is stored in each area. Stored as overlapping area overlapping occurs, the inside of the nodes included in the map data other than the specific layer of the layer, boundary node wherein a node connected to the outside of the overlapping area of the link exiting from the overlapping area Node area correspondence information (33) for associating (87, 98) with the area of the specific layer including the connection destination node (89, 99) that is a node to which the boundary node is connected is stored. .

  Further, the route search device (1) according to claim 2 is the route search device according to claim 1, wherein the specific layer is the highest layer having the least amount of information of the road network among the plurality of layers. It is a layer.

  Further, the route search device (1) according to claim 3 is the route search device according to claim 2, wherein the node area correspondence information (33) includes the highest layer of the plurality of layers. Next, the boundary nodes (87, 98) of the next higher layer having a small amount of road network information are associated with the region of the highest layer including the connection destination nodes (89, 99).

  A route search device (1) according to claim 4 is the route search device according to any one of claims 1 to 3, wherein the route search means (51) includes the departure side and the route search device (51). When a route is searched from the destination side and the search from the departure side overlaps with the search from the destination side, the search cost accumulated from the departure side and the accumulated cost from the destination side are accumulated. Based on the cost addition value calculated by the cost calculation means and the cost addition value calculated by adding the search cost, a route from the departure place to the destination is set. Route setting means (53).

  A route search device (1) according to claim 5 is the route search device according to any one of claims 1 to 4, wherein the map data is stored based on the departure place and the destination. A search target area setting means (54) for setting a search target area, wherein the route search means targets the area set by the search target area setting means from the departure place to the destination. It is characterized by searching for a route to.

Further, the map data (32) according to claim 6 is map data used for the route search of the route search device (1), and is divided into a plurality of areas and a plurality of map data based on the amount of information of the road network. In the plurality of layers, a specific layer overlaps each region, and includes dependency information that associates a parent-child relationship with a region of a higher layer including the region for each region. Without an area, a layer other than the specific layer has an overlapping area in which each area of the map data overlaps, and among the nodes included in the layer other than the specific layer, the overlapping of links exiting from the overlapping area the specific layer including the boundary nodes is a node connected to the outside of the area (87,98), the destination node is a node boundary node is connected to (89,99) Characterized in that it comprises a node region correspondence information (33) for associating the region.

  In the route search device according to claim 1 having the above-described configuration, it is possible to reduce the data size of the map data by reducing the overlap area in the specific layer and reduce the processing time and processing load of the route search processing. It becomes possible. Further, it is possible to prevent a different route from being searched depending on the route search direction and the state of the CPU during the search. In addition, by storing the node area correspondence information, it is possible to appropriately connect the node between the specific layer and a layer other than the specific layer even when the overlapping area of the specific layer is not generated. .

  Further, in the route search device according to claim 2, since the specific layer is the highest layer with the least amount of information of the road network, even when storing so that no overlapping area occurs in the highest layer, It becomes possible to appropriately connect the node to the lower layer. Therefore, even when the departure point and the destination are located at a distance, it is possible to appropriately perform a route search using a plurality of layers including the highest layer.

  In the route search device according to the third aspect, it is possible to appropriately connect the node between the highest layer and the next higher layer, which is a layer communicating with the highest layer.

  Further, in the route search device according to claim 4, when searching from both the starting point and the destination, even if the starting point and the destination are the same, each time the search is performed depending on the state of the CPU at the time of searching. The route can be prevented from being searched.

  Furthermore, in the route search device according to claim 5, since the route from the departure point to the destination is searched for the area specified based on the departure point and the destination, the amount of calculation for the route search is suppressed. be able to. As a result, the processing load on the CPU can be reduced, and the time required for route search can be shortened.

  Furthermore, in the map data according to claim 6, the data size can be reduced by preventing the overlapping area from occurring in the specific layer, and the processing time and processing load of the route search processing using the map data can be reduced. It becomes possible to make it. Further, it is possible to prevent a different route from being searched depending on the route search direction and the state of the CPU during the search. In addition, by including the node area correspondence information, it is possible to appropriately connect nodes between the specific layer and a layer other than the specific layer even when the overlapping area of the specific layer is not generated.

It is the block diagram which showed the navigation apparatus which concerns on this embodiment. It is the figure which showed the various means which navigation ECU comprises. It is the schematic diagram which showed the map data hierarchized by 3 layers memorize | stored in map information DB. It is the figure which showed the structure of each region of layers 1-3. It is the figure which showed the structure of map data. It is a figure explaining the route search process in the case of performing the route search from the departure place to the destination using layers 1-3. It is the figure explaining the connection relation of the node between layer 2 and layer 3 compared with the comparative example. It is the figure explaining the connection relation of the node between layer 2 and layer 3 compared with the comparative example. It is a flowchart of the route search processing program concerning this embodiment. It is the figure shown about each region which comprises general map data. It is the figure explaining the search process of the conventional map data.

  Hereinafter, a route search device according to the present invention will be described in detail with reference to the drawings based on an embodiment in which the navigation device is embodied. First, a schematic configuration of the navigation device 1 according to the present embodiment will be described with reference to FIG. FIG. 1 is a block diagram showing a navigation device 1 according to this embodiment.

  As shown in FIG. 1, the navigation device 1 according to the present embodiment includes a current position detection unit 11 that detects a current position of a vehicle on which the navigation device 1 is mounted, a data recording unit 12 that records various data, A navigation ECU 13 that performs various arithmetic processes based on the input information, an operation unit 14 that receives operations from the user, and a liquid crystal display 15 that displays a map around the vehicle and facility information related to the facility to the user. Communicating between a speaker 16 that outputs voice guidance regarding route guidance, a DVD drive 17 that reads a DVD as a storage medium, and an information center such as a probe center or a VICS (registered trademark: Vehicle Information and Communication System) center And a communication module 18 for performing.

Below, each component which comprises the navigation apparatus 1 is demonstrated in order.
The current position detection unit 11 includes a GPS 21, a vehicle speed sensor 22, a steering sensor 23, a gyro sensor 24, and the like, and can detect the current vehicle position, direction, vehicle traveling speed, current time, and the like. . Here, in particular, the vehicle speed sensor 22 is a sensor for detecting a moving distance and a vehicle speed of the vehicle, generates a pulse according to the rotation of the driving wheel of the vehicle, and outputs a pulse signal to the navigation ECU 13. And navigation ECU13 calculates the rotational speed and moving distance of a driving wheel by counting the generated pulse. Note that the navigation device 1 does not have to include all of the above five types of sensors, and the navigation device 1 may include only one or more of these types of sensors.

  The data recording unit 12 is also a hard disk (not shown) as an external storage device and a recording medium, and a driver for reading the map information DB 31 and a predetermined program recorded on the hard disk and writing predetermined data on the hard disk And a recording head (not shown). The data recording unit 12 may be configured by a memory card, an optical disk such as a CD or a DVD, instead of the hard disk.

  Here, the map information DB 31 is a storage medium in which map data 32 necessary for route guidance and map display is stored. The map data 32 includes, for example, link data regarding roads (links), node data regarding node points, point data regarding points such as facilities, map display data for displaying a map, intersection data regarding each intersection, and between layers. Dependent relationship data for specifying a parent-child relationship of a region, search data for searching for a route, search data for searching for a point, and the like. Further, the map data 32 stored in the map information DB 31 has a structure hierarchized into a plurality of layers based on the difference in the information amount of the road network as will be described later. Furthermore, each layer is divided into a plurality of regions (regions) and stored. Details of the map data 32 will be described later.

  On the other hand, the navigation ECU (Electronic Control Unit) 13 is an electronic control unit that controls the entire navigation device 1. The CPU 41 as an arithmetic device and a control device, and a working memory when the CPU 41 performs various arithmetic processes. Read out from the ROM 43 and the ROM 43 in which a route search processing program (see FIG. 9), which will be described later, is recorded in addition to the RAM 42 for storing route data when the route is searched and the control program. And an internal storage device such as a flash memory 44 for storing the program. The navigation ECU 13 constitutes various means as the processing algorithm shown in FIG. For example, the route search means 51 searches for a route from the departure place to the destination based on the map data 32 stored in the map information DB 31. The route searching unit 51 further includes a cost calculating unit 52 and a route setting unit 53. The cost calculation means 52 searches for the route from the departure side and the destination side, and when the search from the departure side and the search from the destination side overlap, the search cost accumulated from the departure side and A cost addition value obtained by adding the search cost accumulated from the destination side is calculated, and the route setting unit 53 calculates a route from the departure point to the destination based on the cost addition value calculated by the cost calculation unit 52. Set. In addition, the search target area setting unit 54 sets a search target area in the map data based on the departure place and the destination.

  The operation unit 14 is operated when inputting a departure point as a travel start point and a destination as a travel end point, and includes a plurality of operation switches (not shown) such as various keys and buttons. Then, the navigation ECU 13 performs control to execute various corresponding operations based on switch signals output by pressing the switches. The operation unit 14 can also be configured by a touch panel provided on the front surface of the liquid crystal display 15. Moreover, it can also be comprised with a microphone and a speech recognition apparatus.

  The liquid crystal display 15 also includes a map image including a road, traffic information, operation guidance, operation menu, key guidance, a planned travel route from the departure point to the destination, guidance information along the planned travel route, news, weather Forecast, time, mail, TV program, etc. are displayed.

  Further, the speaker 16 outputs voice guidance for guiding traveling along the planned traveling route and traffic information guidance based on an instruction from the navigation ECU 13.

  The DVD drive 17 is a drive that can read data recorded on a recording medium such as a DVD or a CD. Based on the read data, music and video are reproduced, the map information DB 31 is updated, and the like.

  The communication module 18 is a communication device for receiving traffic information composed of information such as traffic jam information, regulation information, and traffic accident information transmitted from a traffic information center, for example, a VICS center or a probe center. For example, a mobile phone or DCM is applicable.

Next, the map data 32 stored in the map information DB 31 will be described.
In this embodiment, the map data 32 is hierarchized into three layers according to the information amount of the road network as shown in FIG. FIG. 3 is a schematic diagram showing map data 32 hierarchized into three layers stored in the map information DB 31. In this case, for example, the level 1 hierarchy (hereinafter referred to as layer 1) is map data divided into a plurality of 10 km square regions, and the level 2 hierarchy (hereinafter referred to as layer 2) is divided into 20 km square regions. The level 3 hierarchy (hereinafter referred to as layer 3) is map data divided into a plurality of 40 km square regions.
The lower level layer contains more information about the road network than the upper level layer. For example, layer 3 stores information on highway automobile national roads, automobile exclusive roads, urban expressways, and toll roads. . Layer 2 stores information about main roads such as national roads and prefectural roads in addition to the road network included in layer 3. In addition to the road network included in layer 2, layer 1 stores information about a detailed road network related to all other general roads such as narrow streets.

  Further, the lower level layer has a narrow coverage area instead of having detailed data, and the upper level layer has a wide coverage area instead of having only coarse data. For example, the lowest level Layer 1 has road data for all roads including narrow streets, but covers only the municipality area, and the highest level Layer 3 only has road data for roads such as expressways and toll roads. Does not have, but covers all over Japan.

  It should be noted that the shape of the relation in each level layer, that is, the size of the range covered by each region can be determined as appropriate. Further, the number of levels constituting the map data, that is, the number of layer layers is not necessarily three layers, and may be two layers or four layers, for example.

Next, each region constituting the map data 32 of each layer will be described.
As shown in FIG. 4, each region 61 that constitutes a layer other than the highest layer 3 among the layers is composed of a core region 62 and an overlap region 63 formed around the core region 62. . On the other hand, the map data 32C of the region 64 that constitutes the uppermost layer 3 has no overlap area and is composed only of the core area 65. That is, the map data of the highest layer 3 is stored so that there is no overlapping area where each region overlaps, and the map data of the other layers 1 and 2 is such that an overlapping area where each region overlaps occurs. Remembered.

  Since the navigation apparatus 1 according to the present embodiment is configured so that there is no overlap area for the layer 3 as described above, the route search direction (departure point → destination, or destination) as in the past. → There is no possibility of searching for different routes depending on the departure location. In particular, even when two CPUs search from both the starting point and the destination, different routes are searched each time the search process is performed, even if the starting point and the destination are the same, depending on the state of the CPU at the time of searching. There is no fear (see FIG. 11).

  Hereinafter, the solution of the conventional problem will be described in more detail with reference to FIG. The example shown in FIG. 4 shows a route search example when the point X is set as the departure point, the point Y is set as the destination, and the region A and the region B are determined as search targets, similarly to FIG. Here, in the example shown in FIG. 4, as a route connecting the point X and the point Y, there are a “lower route” passing through a general road and an “upper route” passing through a toll road. Then, when searching from the starting point from the point X direction to the point Y direction, the node 111 to which the boundary node 110 of the “lower route” region A is connected becomes a node in the core region of the region B. Therefore, the “lower route” is a candidate for a route candidate. However, the node 112 to which the boundary node 110 of the “upper route” region A is connected does not become a node in the core region of the region B (that is, becomes a node in the core region of the region not to be searched). Therefore, the “upper route” is not a candidate for a route candidate (the route is not connected). Accordingly, when a search is performed from the starting point X direction to the point Y direction, only the “lower route” is a route candidate.

  On the other hand, when a search is performed from the destination point Y direction to the point X direction, the node 110 to which the boundary node 111 of the region B of the “lower route” is connected becomes a node in the core region of the region A. Therefore, the “lower route” is a candidate for a route candidate. However, the node 114 to which the boundary node 113 of the “upper route” region B is connected does not become a node in the core region of the region A (that is, becomes a node in the core region of the region not to be searched). Therefore, the “upper route” is not a candidate for a route candidate (the route is not connected). Therefore, even when searching from the destination point Y direction to the point X direction, only the “lower route” becomes a route candidate, and the above-mentioned starting point from the point X direction to the point Y direction is searched. The same guidance route will be set.

Next, details of data constituting the map data 32 will be described.
As shown in FIG. 5, the map data 32 includes map data 32A to 32C of each layer. As described above, the map data 32A to 32C of each layer is configured by map display data, link data, node data, search data, dependency data, facility data, intersection data, search data, and the like. FIG. 5 is a diagram showing the configuration of the map data 32 according to the present embodiment.

  Here, as the map display data, map drawing information for performing map display according to the map data 32A to 32C of each layer is stored.

  The link data includes the width of the road to which the link belongs, the gradient, the cant, the bank, the road surface state, the number of road lanes, for each link constituting the road in the map data 32A to 32C of each layer, Data representing the number of lanes decreasing, width narrowing, railroad crossings, etc. for corners, curvature radius, intersections, T-junctions, corner entrances and exits, etc. Data representing uphill roads, etc. in relation to road types, in addition to general roads such as national roads, prefectural roads, narrow streets, etc. Are recorded respectively. Furthermore, regarding toll roads, data relating to entrance roads (rampways), toll gates (interchanges) and the like of toll roads are recorded.

In addition, as the node data, nodes set at predetermined distances according to the road branch points (including intersections, T-junctions, etc.) and the curvature radius of each road in the map data 32A to 32C of each layer. Point coordinates (position), node attribute indicating whether the node is a node corresponding to the intersection, etc., connection link number list that is a list of link numbers of links connected to the node, other adjacent to the node via the link Data such as the adjacent node number list, which is a list of node numbers of nodes, and the height (altitude) of each node point are recorded.
In addition, as node data, higher-level connection data that specifies connection relationships between nodes in different layers (for example, layer 1 node and layer 2 node, layer 2 node and layer 3 node) is also stored. The
Further, in the present embodiment, as node data, in particular, a node area that associates “a boundary node among layer 2 nodes” and “a layer 3 region including a connection destination node that is a node to which the boundary node is connected”. The correspondence data 33 is also stored. Details of the node area correspondence data 33 will be described later.

Moreover, as search data, it is recorded about the data used when searching and displaying the route to the destination set in the map data 32A to 32C of each layer, and the cost ( Cost data used to calculate the search cost consisting of the cost of the link that constitutes the road (hereinafter referred to as the node cost) and the cost of the link that constitutes the road (hereinafter referred to as the link cost), the travel time required to pass through the link, and the route search. The route is composed of route display data for displaying the route on the map of the liquid crystal display 15.
Here, the node cost is basically set for the node corresponding to the intersection. For example, the presence / absence of a signal and the travel route of the vehicle when passing through the intersection (that is, the type of straight turn, right turn and left turn) The value is determined by.
The link cost is calculated using data related to traffic information such as the degree of congestion acquired as VICS information in addition to the road attributes, road type, road width, number of lanes, and link length constituting the link.

  In addition, as facility data, data related to buildings such as hotels, hospitals, gas stations, parking lots, tourist facilities, interchanges, restaurants, service areas, and the like in each region are recorded together with facility IDs that identify the buildings.

  Further, as the dependency relationship data, data for specifying the parent-child relationship of the regions between layers is stored for each region constituting each layer. Specifically, the data in which the layer 3 region is associated with the layer 2 region included in the region, the layer 2 region is associated with the layer 1 region included in the region Data is stored.

Then, in the area near the starting point and the destination, the navigation device 1 is the map data of the lowest layer around the current location when the route search from the starting point to the destination is a short distance (for example, about 3 km). The route is searched using only the map data of the layer 1 that is.
Also, in the case of a route search where the distance from the current location to the destination is a medium distance (for example, about 50 km), the region of the map data of layer 1 which is the lowest level map data is used for the current location and the vicinity of the destination. The area adjacent to the used layer 1 map data region is searched for a route using the layer 2 map data region which is the intermediate layer map data.
Furthermore, in the case of a route search in which the distance from the current location to the destination is a long distance (for example, about 300 km), the region of the map data of layer 1 that is the lowest level map data around the current location and the destination is used. The area adjacent to the region of the map data of layer 1 used uses the region of the map data of layer 2 which is the map data of the middle layer, and the area adjacent to the region of map data of layer 2 used is the top layer The route is searched using the region of the map data of the layer 3 that is the map data of. In particular, for layer 3, a region to be searched is set in advance based on the position coordinates of the departure point and the destination.
As described above, the amount of calculation for searching for a route can be suppressed, and the time required for the route search can be shortened.

  In addition, when performing a search across a plurality of layers such as the above-mentioned medium distance and long distance, as shown in FIG. 6, when a search within a region constituting a lower hierarchy is reached, the boundary node 71 of the region is reached. The search is continued up to the node (connection destination node) 72 of the upper hierarchy including the boundary node 71. Therefore, in the example shown in FIG. 6, the layer 1 region including the departure point 73 and the destination 74, the region including the connection destination node 72 of the layer 2 connected to the boundary node 71 of the layer 1, and the search target are set. The route search is performed in the layer 3 region. The boundary node 71 is a node connected to the outside of the link exiting from the overlap region 63 for the layer 1 and the layer 2. On the other hand, the layer 3 is a node connected to the inside of the link exiting from the core region 65.

In the present embodiment, as described above, the map data of the layer 3 does not have an overlap area, and is composed only of the core area 65. Therefore, in order to communicate from the layer 2 boundary node 71 to the layer 3 connection destination node 72, the layer 2 boundary node 71 needs to have the node area correspondence data 33.
The reason will be described below.
7 and 8 are diagrams respectively showing a comparative example in which an overlap area is included in the map data of layer 3 and an embodiment in which the overlap area is deleted from the map data of layer 3.

  In the comparative example of FIG. 7, the same node as the boundary node 83 of the region 81 is included in the region 82 of the layer 3 (the region of the layer 3 including the region 81) that has the parent relationship with the region 81 of the layer 2. Therefore, when the boundary node 83 of the layer 2 communicates with the connection destination node 84 of the layer 3, the region of the layer 3 including the connection destination node 84 becomes the region 82 having a parent relationship. Here, as described above, the dependency relationship data for specifying the parent-child relationship of the regions between the layers is included in the map data 32. Therefore, the connection destination node 84 to which the boundary node 83 is connected is connected to the boundary node 83 of the layer 2. It is not necessary to have the node area correspondence data 33 for associating the “layer 3 region including”.

On the other hand, in the embodiment of FIG. 7, the layer 3 region 86 (layer 3 region including the region 85) that is in the parent relationship with the layer 2 region 85 does not include the same node as the boundary node 87 of the region 85. Another adjacent region 88 includes the same node as the boundary node 87 of the region 85. Therefore, when the boundary node 87 of the layer 2 communicates with the connection destination node 89 of the layer 3, the region of the layer 3 including the connection destination node 89 becomes the region 88 having no parent relationship. Accordingly, the layer 2 boundary node 87 corresponds to “layer 3 region 88 including the connection destination node 89 to which the boundary node 87 is connected” in addition to the upper connection data specifying the connection relationship with the connection destination node 89. It is necessary to have node area correspondence data 33 to be attached.
Further, in the embodiment in which the overlap region of layer 3 is deleted as described above, the boundary node of layer 3 is a node connected inside the link exiting from the core region. When communicating from the node to the connection destination node of layer 3, the search route may return to the direction opposite to the search direction (for example, the direction from the destination to the departure point), and the routes may overlap. By providing the node area correspondence data 33 to the boundary node 87, it is possible to prevent such overlapping of paths.

  On the other hand, in the comparative example of FIG. 8, the connection destination node that is the connection destination of the boundary node 93 of the region 91 is connected to the region 92 of the layer 3 (layer 3 region including the region 91) that has the parent relationship 94 is not included, but the node 95 connected to the connection destination node 94 is always included. Therefore, when the boundary node 93 of the layer 2 communicates with the connection destination node 94 of the layer 3, the region of the layer 3 including the node 95 connected to the connection destination node 94 becomes the region 92 having a parent relationship. Here, as described above, the dependency relationship data for specifying the parent-child relationship of the region between layers is included in the map data 32, and the connection relationship between the node 95 and the connection destination node 94 is also stored as node data. It is not necessary for the second boundary node 93 to have the node area correspondence data 33 for associating the “layer 3 region including the connection destination node 94 to which the boundary node 93 is connected”.

On the other hand, in the embodiment of FIG. 8, the connection destination that is the connection destination of the boundary node 98 of the region 96 is connected to the layer 97 of the layer 3 (the layer 3 region including the region 96) that has the parent relationship with the layer 96 of the layer 2. The node 99 is not included, and the node 100 connected to the connection destination node 99 may not be included. Therefore, when the boundary node 98 of the layer 2 contacts the connection destination node 99 of the layer 3, the region of the layer 3 including the connection destination node 99 and the node 100 becomes the region 101 having no parent relationship. Therefore, the layer 2 boundary node 98 corresponds to “layer 3 region 101 including the connection destination node 99 to which the boundary node 98 is connected” in addition to the upper connection data specifying the connection relationship with the connection destination node 99. It is necessary to have node area correspondence data 33 to be attached.
Further, in the embodiment in which the overlap region of layer 3 is deleted as described above, the boundary node of layer 3 is a node connected inside the link exiting from the core region. When communicating from the node to the connection destination node of layer 3, the search route may return to the direction opposite to the search direction (for example, the direction from the destination to the departure point), and the routes may overlap. By providing the node area correspondence data 33 to the boundary node 98, it is possible to prevent such overlapping of routes.

  When the navigation ECU 13 searches for a route, the road data in the search data in the map data is examined, and the search cost (node cost and node cost) for the road (link and node) included in the mesh used for the search is checked. (Link cost) is calculated and a route is searched. Generally, a route search is performed from the destination side, and a value obtained by adding the search costs accumulated from the destination side to the departure point, that is, a cost addition value is calculated. Then, the search conditions (pay road priority, general road priority, distance priority, etc.) are changed, and the route with the smallest cost addition value is guided for each condition. Then, the route selected by the user is set as the guidance route. In addition, in the case of using a search method that searches from both the departure point and the destination by two CPUs, the route is searched from the departure point side and the destination side, and the search from the departure point side and the destination point are performed. When the search from the side overlaps, a value obtained by adding the search cost accumulated from the departure side and the search cost accumulated from the destination side, that is, a cost addition value is calculated.

  Next, a route search processing program executed by the CPU 41 in the navigation device 1 having the above configuration will be described with reference to FIG. FIG. 9 is a flowchart of the route search processing program according to this embodiment. Here, the route search processing program is executed when a predetermined operation (for example, a destination setting operation) for performing a route search is received in the navigation device 1 and searches for a route from the departure point to the destination. It is. Note that the program shown in the flowchart of FIG. 9 below is stored in the RAM 42 or ROM 43 provided in the navigation apparatus 1 and is executed by the CPU 41.

  First, in step (hereinafter abbreviated as S) 1 in the route search processing program, the CPU 41 sets a departure point and a destination based on the received user operation. The departure point may be the current position of the vehicle.

  Next, in S2, the CPU 41 sets the region of layer 3 to be searched based on the departure place and destination set in S1. Specifically, a table indicating the correspondence between the position coordinates of the departure point and the destination and the region to be searched is stored in the RAM 42 and the like, and the position of the departure point and the destination set in S1 is stored. This is done by specifying a region to be searched based on the coordinates and the table.

  Subsequently, in S3, the CPU 41 performs a process for searching for a route from the departure place to the destination set in S1. For layer 3, the route search is performed only for the region set in S2. Then, a cost addition value is calculated for each of a plurality of search conditions (toll road priority, general road priority, distance priority, etc.), and a route with the smallest cost addition value is guided for each condition. For example, a general view of the route is displayed on the liquid crystal display 15 together with the search conditions. Note that only one search condition may be used and only one route having the smallest cost addition value may be guided. The details of the route search process have already been described, and will not be described.

  After that, in S4, the CPU 41 sets the route selected based on the user operation or the like among the routes guided in S3 as the guide route.

  In S <b> 5, the CPU 41 performs traveling guidance using the liquid crystal display 15 and the speaker 16 in accordance with the set guidance route.

As described above in detail, in the navigation device 1 according to the present embodiment, the map data 32 stored in the map information DB 31 is hierarchized into a plurality of layers based on the difference in the information amount of the road network as described later. Each layer is divided into a plurality of regions (regions) and stored. Then, the layer 3 overlap region is deleted so that the layer 3 regions do not overlap each other, and the boundary node of the layer 2 is added to the upper connection data for specifying the connection relationship with the connection destination node of the layer 3 Since the node region correspondence data 33 that associates the layer 3 region including the connection destination node to which the boundary node is connected is also provided, the data size of the map data is reduced, the processing time of the route search processing, It is possible to reduce the processing burden. Further, it is possible to prevent a different route from being searched depending on the route search direction and the state of the CPU during the search. Further, by storing the node area correspondence data 33, it is possible to appropriately connect the nodes between the layer 3 and the layer 2 even when the overlap area of the layer 3 is deleted.
The layer from which the overlap area is deleted is the highest layer 3 with the least amount of information on the road network. Therefore, even when the overlap region is deleted in layer 3, it is possible to appropriately connect the node between layer 3 and layer 2 that communicates with layer 3. Therefore, even when the departure point and the destination are located at a distance, the route search can be appropriately performed using a plurality of layers including the layer 3.
In particular, when a search is performed from both the departure point and the destination by two CPUs, a different route is searched each time the search is performed depending on the state of the CPU even when the departure point and the destination are the same. Can be prevented.
Since the route from the departure point to the destination is searched for the area specified based on the departure point and the destination, the amount of calculation for the route search can be suppressed. As a result, the processing load on the CPU can be reduced, and the time required for route search can be shortened.

Note that the present invention is not limited to the above-described embodiment, and various improvements and modifications can be made without departing from the scope of the present invention.
For example, in the present embodiment, the layer from which the overlap region is deleted is the highest layer 3 with the smallest amount of information on the road network, but the overlap region may be deleted for layers other than the layer 3. In addition, a plurality of layers may be used as a target for deleting the overlap region.

  Also, the number of layer layers is not necessarily three, and may be two or four, for example. Furthermore, the number of layer layers may be different for each region. Furthermore, the shape of each layer (the shape of the core region and the overlap region) can be changed as appropriate.

  The boundary node is a node connected to the outside of the link exiting from the overlap region for layer 1 and layer 2, and the node connected to the inside of the link exiting from the core region for layer 3 However, other nodes may be used as boundary nodes. For example, for layer 1 and layer 2, a node connected to the outside of a link exiting from the overlap region and a node connected via one or more links may be used as a boundary node.

  Moreover, although this embodiment demonstrated the example which applied this invention to the navigation apparatus 1, if it is an apparatus which has a route search function, it is also possible to apply to portable terminals, such as a mobile telephone, a personal computer, etc.

1 Navigation device 13 Navigation ECU
31 Map information DB
32 Map data 33 Node area data 41 CPU
42 RAM
43 ROM
71, 83, 87, 93, 98 Border node 72, 84, 89, 94, 99 Connected node

Claims (6)

A map data storage medium for storing map data;
A route search device having a route search means for searching for a route from a departure place to a destination based on the map data stored in the map data storage medium,
The map data storage medium is
The map data is divided into a plurality of areas, and is layered and stored in a plurality of layers based on the information amount of the road network,
For each area of the map data, store dependency relation information that associates a parent-child relationship with an area of a higher layer including the area ;
Among the plurality of layers, the map data of a specific layer is stored so that there is no overlapping area where each region overlaps, and an overlapping area where each region overlaps the map data of a layer other than the specific layer is generated Remember and
Among nodes included in the map data of a layer other than the specific layer, a boundary node that is a node connected outside the overlapping area of a link exiting from the overlapping area, and a node to which the boundary node is connected A route search apparatus that stores node area correspondence information that associates an area of the specific layer including a certain connection destination node.   The route search apparatus according to claim 1, wherein the specific layer is an uppermost layer having the smallest amount of information of the road network among the plurality of layers.   The node region correspondence information includes the boundary node of the next higher layer having the smallest amount of road network information next to the highest layer of the plurality of layers, and the region of the highest layer including the connection destination node. The route search device according to claim 2, wherein: The route search means includes
When the route is searched from the departure side and the destination side, and the search from the departure side and the search from the destination side overlap, the search cost accumulated from the departure side and the A cost calculating means for calculating a cost addition value obtained by adding the search cost accumulated from the destination side;
Route setting means for setting a route from the departure place to the destination based on the cost addition value calculated by the cost calculation means;
The route search device according to any one of claims 1 to 3, further comprising: A search target area setting means for setting a search target area in the map data based on the departure place and the destination,
5. The route search unit according to claim 1, wherein the route search unit searches for a route from the departure place to the destination with respect to the region set by the search target region setting unit. The described route search device. Map data used for route search by the route search device,
It is divided into multiple areas and is layered into multiple layers based on the amount of information in the road network.
For each of the regions, including dependency information that associates a parent-child relationship with a region of a higher layer including the region ,
Among the plurality of layers, the specific layer does not generate an overlapping area where each region overlaps, and a layer other than the specific layer generates an overlapping area where each region of the map data overlaps,
Among nodes included in layers other than the specific layer, a boundary node that is a node connected to the outside of the overlapping area of a link exiting from the overlapping area, and a connection destination node that is a node to which the boundary node is connected Map data including node area correspondence information for associating an area of the specific layer including

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