WO2009107166A1

WO2009107166A1 - Map display device

Info

Publication number: WO2009107166A1
Application number: PCT/JP2008/000366
Authority: WO
Inventors: 大津留誠
Original assignee: 三菱電機株式会社
Priority date: 2008-02-27
Filing date: 2008-02-27
Publication date: 2009-09-03

Abstract

When display is to be changed over map data, cache data in which corresponding points between cached map data and a connection relation between points on the map are defined in advance, are used to create intermediate map data for use of morphing. The intermediate map data are displayed to morph the display between the map data.

Description

Map display device

The present invention relates to a map display device used for an in-vehicle navigation system or the like.

The function of changing the scale of a map is indispensable for a map display device represented by an in-vehicle navigation system. Such a map display device uses a vector map that expresses roads and background surfaces by vertex data, and manages the map in a hierarchy called a map level. For this reason, when the scale of the map at which the map level is switched is changed, the displayed map may change greatly before and after the switching, and the visibility of the map may be reduced.

In order to solve the above-mentioned problems, it has been proposed to use a technique called morphing to continuously and smoothly change from one map to the other. In order to switch between two objects by morphing, for example, there is a method in which corresponding points between two objects are obtained and linear interpolation is performed between these corresponding points.

To apply such morphing to map display switching, it is necessary to obtain corresponding points between different maps. As a conventional technique for obtaining corresponding points between different maps, for example, there is one described in Patent Document 1. In patent document 1, the corresponding point between different maps is calculated | required by matching the feature point extracted from the handwritten map with the corresponding point in a digital map.

JP 2002-260002 A

In the in-vehicle navigation system, when morphing by changing the scale of the map display, it is not practical unless the map display is switched promptly. However, the conventional techniques including Patent Document 1 do not take into account how quickly the corresponding points necessary for morphing are calculated, and cannot be directly applied to the in-vehicle navigation system.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a map display device capable of performing a process of morphing and switching the map display at high speed.

A map display device according to the present invention obtains a connection relationship between corresponding points and points on a map between map data to be switched, and defines a connection relationship between corresponding points and map points between map data A cache data creation unit that creates data, a cache storage unit that holds the cache data, and an intermediate map data for morphing between map data using the cache data acquired from the cache storage unit is created and displayed between the map data In order to switch, the map display unit is provided that displays intermediate map data and morphs the display between the map data.

According to the present invention, when switching display between map data, intermediate map data for morphing is created using cache data that defines the connection relation between points corresponding to the map data cached in advance and points on the map. In addition, since the intermediate map data is displayed and the display between the map data is morphed, there is an effect that the process of morphing and switching the map display can be performed at high speed.

It is a block diagram which shows the structure of the map display apparatus by Embodiment 1 of this invention. It is a figure for demonstrating the map data hold | maintained in map DB in FIG. It is a figure for demonstrating the map data acquisition process of the map data acquisition part in FIG. It is a figure for demonstrating the calculation process of the corresponding point by the corresponding point calculation part in FIG. It is a figure for demonstrating construction | assembly of the cache data by the cache construction part in FIG. It is a figure which shows the case where the vertex which exists in the map of a detailed scale does not exist in the map of a wide scale. It is a block diagram which shows the structure of the map display apparatus by Embodiment 2 of this invention. It is a figure for demonstrating construction | assembly of the cache data by the cache construction part in FIG.

Hereinafter, in order to describe the present invention in more detail, the best mode for carrying out the present invention will be described with reference to the accompanying drawings.
Embodiment 1 FIG.
1 is a block diagram showing a configuration of a map display device according to Embodiment 1 of the present invention. In FIG. 1, a map display device 1 according to Embodiment 1 includes a cache data creation unit 2, a cache 2 a, a map display unit 6, a control unit 10, and a map database (DB) 11. The map display device 1 is controlled by the control unit 10, and the cache data creation unit 2 and the map display unit 6 operate in response to a processing request from the control unit 10.

The cache data creation unit 2 is a component that creates cache data for map display stored in the cache 2a, and includes a map data acquisition unit 3, a corresponding point calculation unit 4, and a cache construction unit 5. The map data acquisition unit 3 acquires map data (map data of different scales) before and after switching from the map DB 11. Corresponding point calculation unit 4 calculates corresponding points between map data before and after switching. The cache construction unit 5 constructs map display cache data having a data structure that maintains the vertex connection relationship between maps before and after switching.

The map display unit 6 is a component that displays a map using the map display cache data read from the cache 2a, and includes an interpolation point calculation unit 7, a morphing unit 8, and a display unit 9. The interpolation point calculation unit 7 calculates an interpolation point corresponding to a vertex for which no corresponding point is found in the cache data read from the cache 2a. The morphing unit 8 creates an intermediate map in the middle of switching by morphing between maps represented by cache data. The display unit 9 displays the map created by the morphing unit 8.

The map DB 11 is a database that holds map data of a plurality of scales, and manages map data in association with map levels set for each scale, for example.
FIG. 2 is a diagram for explaining the map data held in the map DB in FIG. As shown in FIG. 2, in the map DB 11, it is assumed that map data is hierarchized for each map level (level 0 to 2) according to the display scale (meter scale, 50 m to 5 km).

The cache data creation unit 2, the map display unit 6, and the control unit 10 read software and hardware on this computer by, for example, reading the map display program according to the gist of the present invention into the computer and controlling its operation. It can be realized as a specific means in which the wear cooperates.

Further, the cache 2a and the map database (DB) 11 can be constructed on a storage area of a hard disk device that is standardly installed in the computer. In addition, it may be constructed on a storage device of another computer capable of data communication with the computer.

Next, the operation will be described.
(1) Creation of Cache Data First, the map data acquisition unit 3 of the cache data creation unit 2 reads a plurality of map level map data from the map DB 11 according to the current scale. For example, the map data to be read can be dynamically changed with an intermediate value of a scale that can be displayed at each map level as a boundary.

FIG. 3 is a diagram for explaining the map data acquisition process of the map data acquisition unit in FIG. In FIG. 3, a map with a scale (meter scale) of 50 m and 200 m can be displayed with respect to the map level (level 0). For the map level (level 1), a map having a scale of 500 m or 1 km can be displayed. At this time, the map data acquisition unit 3 receives from the map DB 11 map data having a scale of 50 m to 500 m that can be displayed at level 0 and level 1 with a boundary of 750 m, which is an intermediate value between 500 m and 1 km, that can be displayed at level 1. Read.

Similarly, since a map with a scale of 2 km and 5 km can be displayed with respect to the map level (level 2), the map data acquisition unit 3 sets the intermediate value of 3.5 km as the upper limit boundary, and sets the lower limit boundary as the upper limit boundary. As 750 m, map data of a scale of 1 km to 2 km that can be displayed at level 1 and level 2 is read from the map DB 11. Further, map data of a scale that can be displayed at level 2 and level 3 with 3.5 km as the lower limit boundary is read from the map DB 11.

The map data read from the map DB 11 in this way is output from the map data acquisition unit 3 to the corresponding point calculation unit 4. Note that the map data read by the map data acquisition unit 3 may be selected based on other criteria.

Next, when the corresponding point calculation unit 4 receives the map data from the map data acquisition unit 3, the corresponding point calculation unit 4 calculates the corresponding point between the maps whose map display is to be switched.
FIG. 4 is a diagram for explaining the corresponding point calculation processing by the corresponding point calculation unit in FIG. 1. In the example shown in FIG. 4, vertices B0 to B5 exist on the map at the detailed scale B, but the vertices A0, A1, A2 on the map at the wide scale A and the vertices B0, B1, B2 at the map at the detailed scale B correspond to each other. It becomes a point.

This corresponding point can be obtained by the coordinate determination (matching process) using the fact that the vertex data included in the map at the wide scale A is always included in the map at the detailed scale B. In particular, in the KIWI format used in car navigation, corresponding data can be obtained by specifying an ID. Here, for the vertices B1, B3, and B4 that are not determined to be the same, it is assumed that there is no corresponding point, and the process proceeds to the next process.

Subsequently, the cache construction unit 5 uses the map data of different scales to be switched for map display and the corresponding point information (coordinate data) between the maps of the different scales calculated by the corresponding point calculation unit 4. Build cache data used to switch the display between scale maps. The cache data constructed here has a data structure that maintains the vertex connection relationship between maps of different scales.

FIG. 5 is a diagram for explaining the construction of cache data by the cache construction unit in FIG. 1, and a case where cache data is created from the wide scale A and the detailed scale B for which the calculation of corresponding points is explained in FIG. Show. When the cache construction unit 5 inputs corresponding point data between the maps of the wide scale A and the detailed scale B as shown on the left side of FIG. 5, the cache construction unit 5 creates cache data as shown by the arrows in FIG.

Here, the corresponding points obtained by the corresponding point calculation unit 4 are the same coordinates between the maps of the wide scale A and the detailed scale B. For this reason, the cache construction unit 5 shares the vertex of the wide scale A with the cache data. In the example of FIG. 5, the vertices B0, B2, and B5 in the map with the detailed scale B are shared by the vertices A0, A1, and A2 in the map with the wide scale A, respectively.

The cache construction unit 5 also connects the vertices A0, A1, A2 in the map of the wide scale A (A0-A1-A2) and the vertices B0, B1, B2, B3, B4, B5 in the map of the detailed scale B. The information specifying the connection relationship (B0-B1-B2-B3-B4-B5) is included in the cache data. Thereby, in the cache data, the connection relationship between the vertices A0, A1, and A2 in the map of the wide scale A and the connection relationship of the vertices B0, B1, B2, B3, B4, and B5 in the map of the detailed scale B are maintained. .

In the example shown on the right side of FIG. 5, the vertices A0, A1, and A2 in the map of the wide scale A are connected by solid lines, respectively, and the vertices B0 (A0), B1, B2 (A1), B3, and B4 in the map of the detailed scale B are connected. By connecting B5 (A2) with broken lines, the structure of the cache data maintaining the vertex connection relationship in the map of the wide scale A and the detailed scale B is schematically expressed.

In the cache data constructed in this way, based on the vertex connection relationship in the map of the wide scale A and the detailed scale B, the vertex corresponding to the vertices B1, B3, B4 where no corresponding point exists is added to which position. You can easily ask for it.

In the example shown in FIG. 5, it is possible to specify that the vertex B1 exists between the vertices A0 and A1 from the connection relationship of the vertices (nodes). Therefore, an interpolation point may be added between the vertex A0 and the vertex A1 (A0-A1). Similarly, the presence of vertices B3 and B4 can be specified between vertices A1 and A2, and interpolation points corresponding to vertices B3 and B4 are added between vertex A1 and vertex A2 (A1-A2).

Note that, as shown in FIG. 6, the vertex existing in the map of the detailed scale B may not exist in the map of the wide scale A. In this case, the cache construction unit 5 constructs cache data by adding one of the vertices located at the end points to the map of the wide scale A from the connection relation of the vertices on the map of the detailed scale B.

In the example of FIG. 6, the vertex B0 located at the end point is the vertex from the connection relationship (B0-B1-B2-B3-B4-B5) of the vertex B0, B1, B2, B3, B4, B5 in the map of the detailed scale B. A0 is added to the map of wide scale A. In addition to the case shown in FIG. 6, any one of the vertices B1, B2, B3, B4, and B5 on the detailed scale B map may be added to the wide scale A map.

The cache construction unit 5 holds the cache data constructed as described above in the cache 2a.

(2) Map Display Processing When the user requests a map display scale change via an input device (not shown), the control unit 10 continuously issues processing requests regarding map display switching to the map display unit 6. Output to. The map display unit 6 switches the map display while performing morphing using the cache data read from the cache 2a in response to a processing request from the control unit 10.

First, when the interpolated point calculation unit 7 of the map display unit 6 reads cache data between maps in response to the scale change request from the cache 2a, the interpolated point calculation unit 7 calculates interpolated points for vertices for which no corresponding points exist between the maps. For example, in the case of FIG. 5, the interpolation point calculation unit 7 determines that the vertex A0 in the map of the wide scale A is based on the connection relation of the vertices in the map of the wide scale A and the detailed scale B defined in the cache data. One point is added between the vertex A1 (A0-A1) and two points between the vertex A1 and the vertex A2 (A1-A2), and interpolation points are added at the same ratio as the map of the detailed scale B.

That is, when the interpolation point is C, the interpolation point is added on the straight line connecting the vertex A0 and the vertex A1 (A0-A1) so that the following expression (1) is established. In the following formula (1), a vector A ₀ C is a vector defined by the vertex A0 and the interpolation point C, and a vector CA ₁ is a vector defined by the interpolation point C and the vertex A1. The vector B ₀ B ₁ is a vector defined by the vertices B0 and B1, and the vector B ₁ B ₂ is a vector defined by the vertices B1 and B2.

Further, in the case where no corresponding vertex exists as shown in FIG. 6, the corresponding point of the vertices B1, B2, B3, B4, and B5 in the detailed scale B map is set to A0 added by the cache construction unit 5. That's fine. Note that interpolation points may be added by methods other than those described above.

Interpolation point calculation unit 7 can correspond between different scale maps by using cache data including corresponding points that are set as vertices of the same coordinates between the maps and that define the connection relationship between the vertices in both maps. Interpolation points for vertices that do not have points can be easily obtained.

That is, it is only necessary to extract vertices that are not set as vertices of the same coordinates between maps, and sequentially add interpolation points corresponding to the extracted vertices based on the connection relationship of the vertices. Therefore, it is possible to reduce the calculation load required for the interpolation point addition process, and it is possible to add interpolation points at high speed.

When an interpolation point is added by the interpolation point calculation unit 7, the morphing unit 8 creates an intermediate map between maps to be processed in accordance with a processing request from the control unit 10. Here, in the intermediate map between maps, the transition of the map including the corresponding points from the map before switching to the map after switching is expressed while maintaining the connection relationship of the vertices on the map.

For morphing, a method of linearly interpolating between two corresponding vertices can be used. In this method, an intermediate map C is generated by the following equation (2) for two vector maps A and B to be morphed. Here, α is a numerical value representing the degree of change in scale. The morphing method itself may use a method other than linear interpolation.

The display unit 9 displays the intermediate map generated by the morphing unit 8 on the display screen according to the processing request from the control unit 10 when switching the display between different scale maps. Thereby, according to the scale change from a user, map display is switched by morphing.

As described above, according to the first embodiment, the connection relationship between the points on the map to be switched and the points on the map is obtained, and the connection between the points on the map and the points on the map is obtained. Using the cache data creation unit 2 that creates the cache data that defines the relationship, the cache 2a that holds the cache data, and the cache data acquired from the cache 2a, intermediate map data for morphing between the map data is created, When switching the display between the data, a map display unit 6 that displays intermediate map data and morphs the display between the map data is provided.
By configuring in this way, it is possible to easily obtain the correspondence between maps of different scales to be switched from the cache data, and as a result, it is possible to perform map display while performing morphing at high speed. .

Embodiment 2. FIG.
In the first embodiment, the case of performing the process of adding an interpolation point at the time of map display has been shown. However, in this second embodiment, cache data to which an interpolation point has been added is created, and the map is displayed. Only the morphing process is performed.

FIG. 7 is a block diagram showing a configuration of a map display device according to Embodiment 2 of the present invention. 7, the map display device 1 according to the second embodiment includes a cache data creation unit 2A, a cache 2b, a map display unit 6a, a control unit 10, and a map DB 11. Similar to the first embodiment, the map display device 1 is controlled by the control unit 10, and the cache data creation unit 2A and the map display unit 6a operate in response to a processing request from the control unit 10.

The cache data creation unit 2A is a component that creates cache data for map display stored in the cache 2b, and includes a map data acquisition unit 3, a corresponding point calculation unit 4, an interpolation point calculation unit 7a, and a cache construction unit 5a. . The interpolation point calculation unit 7a calculates an interpolation point corresponding to the point for which the corresponding point was not calculated by the corresponding point calculation unit 4. The cache construction unit 5a uses the map data to be processed, the information on the corresponding points calculated by the corresponding point calculation unit 4, and the information on the interpolation points calculated by the interpolation point calculation unit 7a to be used for display switching between maps. Build data.

The map display unit 6a is a component that displays a map using cache data for map display read from the cache 2b, and includes a morphing unit 8 and a display unit 9. In FIG. 7, the same reference numerals are given to components that operate the same as or similar to those in FIG. 1, and redundant descriptions are omitted.

The cache data creation unit 2A, the map display unit 6a, and the control unit 10 read software and hardware on this computer by, for example, reading the map display program according to the gist of the present invention into the computer and controlling its operation. It can be realized as a specific means in which the wear cooperates.

Further, the cache 2b and the map DB 11 can be constructed on a storage area of a hard disk device that is standardly installed in the computer. In addition, it may be constructed on a storage device of another computer capable of data communication with the computer.

Next, the operation will be described.
(1) Creation of Cache Data First, the map data acquisition unit 3 of the cache data creation unit 2A reads a plurality of map level map data from the map DB 11 according to the current scale. When the corresponding point calculation unit 4 receives the map data from the map data acquisition unit 3, the corresponding point calculation unit 4 calculates corresponding points between maps of different scales to be switched for map display in the same manner as in the first embodiment.

Next, when the interpolation point calculation unit 7a inputs the map data to be processed and the information of the corresponding points from the corresponding point calculation unit 4, the interpolation point calculation unit 7a calculates the interpolation points for the vertices for which no corresponding point exists between the maps. Here, the interpolation point calculation unit 7a specifies the position to add the interpolation point from the vertex connection relationship between the processing target maps.

Subsequently, the cache construction unit 5a, the map data of different scales to be processed, the information of the corresponding points between the maps of the different scales calculated by the corresponding point calculation unit 4, and the interpolation calculated by the interpolation point calculation unit 7a. From the point information, the cache data used for switching the display between the different scale maps is constructed. The cache data constructed here has a data structure that maintains the connection relationship of vertices including interpolation points between maps of different scales.

FIG. 8 is a diagram for explaining the construction of the cache data by the cache construction unit in FIG. 7, and the cache is obtained from the wide scale A and the detailed scale B which explained the calculation of corresponding points in FIG. 4 in the first embodiment. The case of creating data is shown. When the cache construction unit 5a inputs the corresponding point data between the maps of the wide scale A and the detailed scale B as shown on the left side of FIG. 8 and the data of the interpolation points C0, C1, C2 corresponding to the vertices B1, B3, B4. Then, cache data as shown by an arrow in FIG. 8 is created.

In FIG. 8, an interpolation point C0 is added between the vertex A0 and the vertex A1 (A0-A1). Further, interpolation points C1 and C2 corresponding to the vertices B3 and B4 are added between the vertices A1 and A2 (A1-A2) in accordance with the connection relationship between the vertices B3 and B4 in the detailed scale B map. As described above, the cache construction unit 5a constructs cache data including information that sets the corresponding points including the interpolation points between the maps as the vertices of the same coordinate and defines the connection relationship between the vertices in both maps. 2b.

(2) Map Display Processing When a map display scale change request is made by the user via an input device (not shown), the control unit 10 continuously issues processing requests regarding map display switching to the map display unit 6a. Output. The map display unit 6a switches the map display while performing morphing using the cache data read from the cache 2b in response to a processing request from the control unit 10.

The morphing unit 8 creates an intermediate map between maps to be processed using cache data read from the cache 2b in response to a processing request from the control unit 10. For the cache data held in the cache 2b, the corresponding point between maps is completely required by the cache data creation unit 2A.

As described above, according to the second embodiment, the cache data creation unit 2A calculates an interpolation point for a point that has no corresponding point and exists only in one of the display switching target map data. 7a, the cache data defining the connection relation between the corresponding points between the map data including the interpolation points calculated by the interpolation point calculation unit 7a and the points on the map is created and held in the cache 2b, and is displayed on the map. The unit 6a creates intermediate map data using the cache data acquired from the cache 2b, and displays the intermediate map data to morph the display between the map data when switching the display between the map data.
By creating in advance cache data that has been added up to the addition of interpolation points in this way, there is no need to perform interpolation point addition processing at the time of map display, and the map can be made faster than in the first embodiment. It is possible to display.

The map display device according to the present invention is suitable for an in-vehicle navigation system because morphing is applied to map display switching so that smooth switching can be performed with good visibility even between maps of different scales. .

Claims

Cache data creation for determining the connection relationship between corresponding points and points on the map between the map data to be switched, and creating cache data defining the connection relationship between the corresponding points and the points on the map And
A cache storage unit for holding the cache data;
The intermediate map data for morphing between the map data is created using the cache data acquired from the cache storage unit, and when the display is switched between the map data, the intermediate map data is displayed and the map data is A map display device comprising a map display unit for morphing the display.
2. The map display according to claim 1, wherein the cache data creation unit includes a map data acquisition unit that acquires map data according to a display scale from a map data storage unit that stores map data for each display scale. apparatus.
The map display section
A point corresponding to the cache data is not defined, and an interpolation point calculation unit that calculates an interpolation point for a point that exists only in one of the map data to be switched is provided.
Specify the interpolation point calculated by the interpolation point calculation unit for the cache data,
The intermediate map data is created using the cache data, and the display between the map data is morphed by displaying the intermediate map data when switching the display between the map data. Map display device.
The cache data creation part
There is an interpolation point calculation unit that calculates an interpolation point for a point that does not have a corresponding point and exists only in one of the map data to be switched,
Create cache data that defines the connection relationship between the corresponding points and the points on the map between the map data including the interpolation points calculated by the interpolation point calculation unit, and hold in the cache storage unit,
The map display section
The intermediate map data is created using the cache data acquired from the cache storage unit, and when the display is switched between the map data, the intermediate map data is displayed and the display between the map data is morphed. The map display device according to claim 1.