Device and method for evaluating road maps

Abstract

The invention relates to a device for evaluating road maps, wherein each road map has grid points and lines which connect the grid points and represent the geometry of the roads. The device is designed to divide at least two road maps into tiles and to select a tile from each road map, wherein the geographical area of each of the selected tiles is identical. The device is also designed to compare the grid points and connecting lines in the selected tiles with one another and to determine a degree of differentiation of the road maps on the basis of a result of the comparison.

Description

[0001] Device and method for evaluating road maps

[0002] Description

[0003] The present invention relates to a device for evaluating road maps according to claim 1. The present invention further relates to a method for evaluating road maps according to claim 9.

[0004] Road maps can be used, for example, in vehicle navigation systems. Such road maps, or map products in general, are subject to continuous change processes. On the one hand, new roads should be integrated into the maps as quickly as possible, for example, to enable accurate navigation based on current conditions. On the other hand, maps are continuously improved and adapted using new data from map manufacturers. Such data includes, for example, speed limits, which can be recorded by vehicle sensors and passed on to the map manufacturers.

[0005] The frequency of road map updates and the delivery of new map products has increased compared to the past, although the differences between the different versions of a road map can be very small. Therefore, updating a road map loaded into a navigation system is not always necessary with each new version of the road map. However, it is not always immediately clear whether such an update is advisable or not. The differences between road maps from different manufacturers are also not always easy to identify.

[0006] The present invention is therefore based on the object of providing a way to compare road maps with each other in a simple manner. This object is achieved by a device for evaluating road maps according to claim 1 and a method for evaluating road maps according to claim 9.

[0007] The device for evaluating road maps is designed to compare two or more road maps with each other. Each road map has reference points and lines connecting the reference points, which represent the geometry of the roads. In order to compare two or more road maps, the device is designed to divide the road maps into respective tiles and to select a tile from each road map, wherein the geographical area of ​​the respectively selected tiles is identical. By selecting such geographical areas or dividing the respective maps into tiles, the device can compare road maps with different scales with each other, since the comparison always takes place between tiles that cover the same geographical area.

[0008] The device is then configured to compare the vertices and connecting lines in the selected tiles with each other and, based on the result of the comparison, to determine a degree of differentiation between the road maps. Since the comparison takes place between tiles with the same geographical area, this comparison can be applied to any road map scale and is therefore flexibly scalable. Furthermore, the device can perform the comparison automatically, without manual intervention, for example, with every available road map update.

[0009] Since the device compares the reference points and connecting lines, i.e., the road network, the degree of discrimination can, in particular, indicate a difference between the road networks of different road maps. This degree of discrimination can then be used, for example, to decide on an update of the road maps in a navigation system or on the quality of a road map. The device can, for example, be implemented in a vehicle to compare road maps there. The device can also be implemented as a cloud solution or on any computer.

[0010] According to one embodiment, the device is configured to convert the selected tiles into pixel representations and compare the pixels of the tiles. To convert the selected tiles into pixel representations consisting of a plurality of pixel values, any image processing method that can process an image, i.e., the content of the respective tile, and convert it into pixel values ​​can be used. These include, for example, standard rendering methods that convert the geo-coordinates from a street map into corresponding image coordinates.

[0011] Any other methods may be used, but the same method should be used for the road maps to be compared to enable a reliable comparison of the content that is not distorted by different conversion methods. Furthermore, the number of pixels of the tiles to be compared should be identical to enable a pixel-to-pixel comparison between the tiles.

[0012] The following example describes the comparison of two tiles. This can be applied analogously to the comparison of more than two tiles. If two pixels in the tiles being compared are identical, this pixel is counted as "same"; otherwise, it is considered "different." In this way, the degree of differentiation between the tiles being compared can be determined simply by counting the number of identical and different pixels. This comparison can be performed for all geographical areas of the road maps by comparing all tiles. The result is then a degree of differentiation of the entire road maps from each other.

[0013] The tiles can have pixels as pure black and white values. Alternatively, the pixels can also represent the color space and color depth. For example, in another embodiment, the road maps can have attributes represented by the color values ​​of the pixels. In this way, not only the road network itself but also additional information from the road maps can be compared.

[0014] The attributes can include, among other things, speed limits, road boundaries, road types, and / or points of interest. These attributes can be stored in the road maps and are taken into account by the device when comparing the road maps. The transfer of the attributes into pixel values ​​can occur during the processing of the road maps or tiles and their conversion into pixel values.

[0015] According to a further embodiment, the road maps are different versions of a road map from a single source, for example, from a manufacturer. In this case, the degree of differentiation can particularly indicate a degree of change in the road maps. The degree of differentiation can thus be used to detect the extent to which the road map has changed from one version to a newer version. This information can, for example, be used to decide whether an update of a road map in a navigation system is necessary. If the maps differ only slightly, an update may be omitted for reasons of time, cost, and / or storage. If the degree of change is high, an update may, in turn, be urgently recommended, and the device can, for example, output this information to a user of a navigation system.

[0016] According to another embodiment, the degree of discrimination indicates the ratio of different pixels to the total number of pixels. This ratio can be referred to as the Changed Geometry Indicator (CGI). The CGI can range from 0 to 100, where 0 corresponds to no change and 100 corresponds to a change in all pixels.

[0017] Another metric that can be used as a comparison result is the New Geometry Indicator (NGl), which represents the ratio of newly added or removed geometries. The larger the value (>0), the more new roads there are; the smaller the value (<0), the fewer roads there are. The degree of differentiation can also be indicative of the level of detail of the road maps. This information can be used, in particular, to compare road maps from different manufacturers.

[0018] According to a further embodiment, the device is configured to output the determined degree of discrimination. As already explained above, the device can output the degree of discrimination, for example, to a user in order to simplify the user's decision regarding an update of the road map. The device can also output the degree of discrimination to any other device, for example, a computing device, for further processing. For example, such a computing device can initiate an automatic update of road maps.

[0019] According to another aspect, a method for evaluating road maps is proposed, wherein each road map has vertices and lines connecting the vertices that represent the geometry of the roads. The method comprises the following steps: dividing at least two road maps into respective tiles, selecting a tile from each road map, wherein the geographical area of ​​the respectively selected tiles is identical, comparing the vertices and connecting lines in the selected tiles, and determining a degree of discrimination between the road maps based on a result of the comparison.

[0020] The embodiments and features described for the proposed device apply accordingly to the proposed method.

[0021] Furthermore, a computer program product is proposed which has a program code which is designed to cause the method as explained above to be carried out on a computer.

[0022] A computer program product, such as a computer program means, can be provided or delivered, for example, as a storage medium, such as a memory card, USB stick, CD-ROM, DVD, or in the form of a downloadable file from a server in a network. This can be done, for example, in a wireless communications network by transmitting a corresponding file with the computer program product or the computer program means.

[0023] Further possible implementations of the invention also include combinations of features or embodiments described above or below with respect to the exemplary embodiments that are not explicitly mentioned. In this case, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the invention.

[0024] Further advantages and advantageous embodiments are set forth in the description, the drawings, and the claims. In particular, the combinations of features set forth in the description and the drawings are purely exemplary, so the features may also be present individually or in other combinations.

[0025] The invention will be described in more detail below with reference to exemplary embodiments illustrated in the drawings. The exemplary embodiments and the combinations shown in the exemplary embodiments are purely exemplary and are not intended to define the scope of the invention. This scope is defined solely by the appended claims.

[0026] They show:

[0027] Fig. 1 : a schematic block diagram of a device for evaluating road maps; and

[0028] Fig. 2 to 4: Examples of comparing road maps.

[0029] In the following, identical or functionally equivalent elements are identified by the same reference symbols.

[0030] Fig. 1 shows a device V for evaluating road maps. In the embodiment shown, two road maps are compared. However, it should be noted that more than two road maps can also be compared.

[0031] To compare the road maps, device V first divides the respective road map into tiles and then compares two tiles K1, K2, one from each road map. Tiles K1, K2 each show the same geographical area to enable comparison of the road maps.

[0032] The road maps each consist of vertices and lines connecting the vertices, representing a road network. To compare the road maps, the device V compares the vertices and connecting lines present in the selected tiles and determines a degree of discrimination U of the road maps based on the result of the comparison.

[0033] This comparison can, for example, be performed pixel-based, as shown in Fig. 2. To do so, the device V can first convert the tiles K1, K2 into pixel representations. In the example shown in Fig. 2, the pixel values ​​consist of binary values, i.e., black and white values. However, the pixels can also include color values, which can represent, for example, other attributes of the road maps, such as speed limits or other information.

[0034] Device V first divides the road maps to be analyzed into geographically unique tiles. This allows for a scalable and parallelized evaluation. Subsequently, the geometric vertices and the lines between these vertices are determined and plotted per tile K1, K2 in a pixel image, as shown in Fig. 2. The two images are the same size and are then compared pixel-by-pixel.

[0035] Tile K1 has pixel values ​​P1 (black or set pixels) and pixel values ​​P2 (white or unset pixels). The black pixel values ​​P1 can represent streets, for example. Tile K2 has pixel values ​​P3 (black or set pixels) and pixel values ​​P4 (white or unset pixels). The black pixel values ​​P3 can also represent streets.

[0036] If the device V now compares the two tiles K1, K2 with each other, a delta pixel representation D results, which represents the degree of discrimination U. As can be seen, the delta pixel representation D contains pixel values ​​P5 (black pixels) and pixel values ​​P6 (white pixels). The pixel values ​​P5 represent pixels that differ between tiles K1 and K2, whereas the pixel values ​​P6 represent pixels that are identical for both tiles K1 and K2.

[0037] Thus, if two pixels in both tiles K1 and K2 are identical, this pixel is counted as "equal" and stored as pixel value P6 in the delta pixel representation D. If a pixel is set in tile K1 but not in tile K2, this is a changed pixel and is stored as pixel value P5. If a pixel is set in tile K1 but not in tile K2, this is also a changed pixel and is stored as pixel value P5. The result thus indicates the number of changed pixels and the number of pixels that remained the same in the delta pixel representation D.

[0038] The resulting degree of discrimination U can be used to generate various metrics. These include, for example, a Changed Geometry Indicator (CGI), which is the ratio of changed pixels to the number of pixels with a value between 0 and 100, where 0 = no change, 100 = all changed. Another metric is a New Geometry Indicator (NGl), which is the ratio of newly added or removed geometries: the larger the value (>0), the more new roads; the smaller the value (<0), the fewer roads.

[0039] Fig. 3 shows an example of a tile whose delta pixel representation D was determined between different versions of the same road map. On the left, the two tiles K1, K2, each assigned to different versions of the road map, are superimposed. A comparison of the two tiles K1, K2 results in the pixel-based delta D, which is shown on the right. In this case, there were clear changes when comparing the first to the second tile K1, K2. This can also be seen in the CGI, which in this case could be 37, for example. The NGl could be relatively low, i.e. no new road network was added or removed.

[0040] Fig. 4 also shows a tile whose delta pixel representation D was determined between different versions of the same road map. As in Fig. 3, on the left-hand side the two tiles K1, K2, each assigned to different versions of the road map, are superimposed. Comparing the two tiles K1, K2 results in the pixel-based delta D, which is shown on the right-hand side. In this case, there were relatively few changes when comparing the first to the second tile K1, K2. This can also be seen in the CGI, which in this case could be, for example, 1.69.

[0041] In summary, the device proposed here provides a simple way to compare road maps of different versions and / or from different manufacturers in a scalable and flexible manner.

[0042] Reference symbol

[0043] D Difference / Delta

[0044] K1 first tile

[0045] K2 second tile

[0046] P1-P6 pixels

[0047] U Degree of discrimination

[0048] V device

Claims

Device and method for evaluating road maps Claims:

1. Device (V) for evaluating road maps, wherein each road map has support points and lines connecting the support points, which represent the geometry of the roads, characterized in that the device (V) is designed to divide at least two road maps into respective tiles (K1, K2) and to select a tile (K1, K2) from each road map, wherein the geographical area of ​​the respectively selected tiles (K1, K2) is identical, and wherein the device (V) is designed to compare the support points and connecting lines in the selected tiles (K1, K2) with one another and to determine a degree of discrimination (U) of the road maps based on a result of the comparison.

2. Device according to claim 1, characterized in that the device (V) is designed to convert the selected tiles (K1, K2) into pixel representations and to compare the pixels (P1, P2, P3, P4) of the tiles (K1, K2).

3. Device according to claim 2, characterized in that the road maps have attributes which are represented by color values ​​of the pixels (P1, P2, P3, P4).

4. Device according to claim 3, characterized in that the attributes include speed limits, road boundaries, road types and / or points of interest.

5. Device according to one of the preceding claims, characterized in that the road maps have different versions of a Road maps are from one source and that the degree of discrimination (U) indicates a degree of change in the road maps.

6. Device according to one of the preceding claims, characterized in that the degree of discrimination (U) indicates the ratio of the different pixels (P1, P2, P3, P4) to the total of the pixels (P1, P2, P3, P4).

7. Device according to one of the preceding claims, characterized in that the degree of discrimination (U) is indicative of the level of detail of the road maps.

8. Device according to one of the preceding claims, wherein the device (V) is designed to output the determined degree of discrimination (U) and / or to provide it to further devices.

9. A method for evaluating road maps, each road map having support points and lines connecting the support points which represent the geometry of the roads, characterized in that the method comprises: dividing at least two road maps into respective tiles (K1, K2), selecting a tile (K1, K2) from each road map, the geographical area of ​​the respectively selected tiles being identical, comparing the support points and connecting lines in the selected tiles (K1, K2) and determining a degree of discrimination (U) of the road maps based on a result of the comparison.

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