JP2009085734A - Drawing data creation method, navigation apparatus, map drawing method and map drawing program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drawing data creation method, a navigation apparatus, a map drawing method and a map drawing program for identifiably displaying relative heights of roads. <P>SOLUTION: A navigation unit 2 for displaying a map screen 5a on a display 5 comprises: a geographic information storage section 15 for adjusting a horizontal coordinate of an interchange point configured so as to indicate a vertical relationship between the roads and hierarchies for indicating the vertical relationship of roads at the interchange point in response to a hierarchical transition between peripheral hierarchy configuration points, and storing the horizontal coordinate and the hierarchies per road; and an image processor 18 for identifiably drawing the vertical relationship between the roads at the interchange point based on the horizontal coordinate of the interchange point and hierarchies configured for roads. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a drawing data creation method, a navigation device, a map drawing method, and a map drawing program.

  The navigation device stores map drawing data for drawing roads and the like on the map screen. This map drawing data has background data for drawing urban areas, rivers, facilities, and the like, and road drawing data for drawing road shapes. The navigation device reads the map drawing data of the designated area and displays the background image and the road image on the map screen.

However, since the conventional navigation device does not display the vertical relationship between the three-dimensionally intersecting roads in an identifiable manner, the user cannot distinguish the intersection and the three-dimensional intersection on the map screen. On the other hand, Patent Document 1 describes a navigation device that stores a pattern pattern of a three-dimensional intersection. This pattern is illustration data created in advance, and when the vehicle approaches a three-dimensional intersection, the device determines whether or not there is a pattern corresponding to the three-dimensional intersection. If prepared, the pattern is output to the display. For example, when entering from an expressway, voice guidance such as “get on the expressway” is performed.
JP 2002-236026 A

  However, since the image based on the picture pattern is an illustration of a solid intersection seen from a predetermined point, the image can be displayed only for a short time. In addition, in order to prepare the above-described pattern pattern for each stereoscopic display point, a great deal of labor is required in the process of creating map drawing data, and the amount of data stored in the apparatus is enormous, which is not practical.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a drawing data creation method, a navigation device, a map drawing method, and a map that can display the relative height of each road in an identifiable manner. To provide a drawing program.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a drawing data creation method for creating map drawing data, wherein a hierarchy setting point indicating a vertical relationship of each road is set, and at the hierarchy setting point, Each level indicating the vertical relationship of each road is adjusted in accordance with the level transition between the level setting points around it and each level is registered in association with the two-dimensional coordinates of the level setting points. Is the gist.

  The invention according to claim 2 is a navigation device for displaying a map screen on a display means, a horizontal coordinate storage means for storing two-dimensional coordinates of a hierarchy setting point set to indicate a vertical relationship of each road, A hierarchy storage means for adjusting each hierarchy indicating the upper and lower relations of each road at a hierarchy setting point according to a hierarchy transition with the surrounding hierarchy setting points and storing for each road; Image processing means for rendering the upper and lower relations of the roads at the hierarchy setting points in an identifiable manner based on the two-dimensional coordinates of the hierarchy setting points and the hierarchies set for the roads; The summary is provided.

  According to a third aspect of the present invention, in the navigation device according to the second aspect, the tier suppresses undulation of the tier with respect to the tier set point when the tier set point is continuous on the same road. The gist is that the level is adjusted for the other road on the upper side or the lower side at the level setting point where the adjustment is performed, along with the adjustment to the level setting point.

  According to a fourth aspect of the present invention, in the navigation device according to the third aspect, the hierarchy is adjusted to a hierarchy in which the slope of each successive hierarchy setting point on the same road is less than a predetermined value. Is the gist.

  The invention according to claim 5 is the navigation device according to any one of claims 2 to 4, wherein the two-dimensional coordinates of the shape interpolation point set between the successive set points of the same road , Further comprising interpolation data storage means for storing height coordinates of each shape interpolation point given based on the difference of each hierarchy of each hierarchy setting point, and the image processing means comprises a height of the shape interpolation point The gist is to draw the road shape based on the coordinates.

  The invention according to claim 6 is the map drawing method for displaying the map screen on the display means, and the two-dimensional coordinates of the hierarchy setting point set to indicate the vertical relationship of each road, and the hierarchy setting point. Each level indicating the vertical relationship of each road is set in association with each road, and each level at the level setting point is adjusted according to the level transition between the level setting points around it. Then, based on the two-dimensional coordinates set at the level setting point and the levels set for the roads, the vertical relations of the roads at the level setting points are drawn in an identifiable manner. This is the gist.

  According to a seventh aspect of the present invention, in the map drawing method according to the sixth aspect of the present invention, when there is each of the hierarchy setting points that are continuous on the same road, the adjustment for suppressing the undulation of the hierarchy with respect to the hierarchy setting point. The gist is to adjust the hierarchy for the other road on the upper side or the lower side at the adjusted hierarchy setting point.

  The invention according to claim 8 is the map drawing method according to claim 7, wherein, when different levels are set at the consecutive level setting points on the same road, the gradient of the level is large. Accordingly, the level of one road at the level setting point is adjusted, and the level for the other road that is vertically related at the level setting point is adjusted in accordance with the adjustment for the level setting point. Is the gist.

  The invention according to claim 9 is the map drawing method according to any one of claims 6 to 8, wherein each of the shape interpolation points set between the successive setting points of the same road is set to each of the shape interpolation points. The gist is to provide the height coordinates of each shape interpolation point based on the difference of each layer of the hierarchy setting point, and to draw the road shape based on the height coordinate of the shape interpolation point.

  The invention according to claim 10 is a map drawing program for outputting a map screen to a display means using a control means for drawing a map, wherein the control means is a hierarchy set to indicate the vertical relationship of each road. The horizontal coordinate acquisition means for acquiring the two-dimensional coordinates of the set point, and the vertical relationship of each road at the level set point, the level adjusted according to the level transition between the level set points around it Based on the hierarchy acquisition means to be acquired, the two-dimensional coordinates of the hierarchy setting point, and each hierarchy set for each road, the vertical relationship of each road at the hierarchy setting point can be identified The gist is to make it function as an image processing means for drawing.

  According to the method of claim 1, a hierarchy setting point indicating the vertical relationship of each road is set, and a hierarchy indicating the vertical relationship of each road at the hierarchy setting point is associated with the two-dimensional coordinates of the hierarchy setting point. Registered. Moreover, the hierarchy is adjusted according to the vertical relationship between adjacent hierarchy setting points. For this reason, it is possible to reduce the amount of data stored in the device by making the information indicating the vertical relationship of the road simple, and to make the road image an image along the scenery that is actually visually recognized. it can.

  According to the structure of Claim 2, the navigation apparatus has a hierarchy which shows the vertical relationship of each road. Moreover, the hierarchy is adjusted according to the vertical relationship between adjacent hierarchy setting points. For this reason, it is possible to reduce the amount of data stored in the device by making the information indicating the vertical relationship of the road simple, and to make the road image an image along the scenery that is actually visually recognized. it can.

  According to the configuration of the third aspect, the hierarchy is adjusted to suppress undulations when there are a plurality of hierarchy setting points on the same road. In addition, the level of the other road in the vertical relationship at the level setting point where the undulation is suppressed is adjusted in accordance with the adjustment. For this reason, it is possible to draw a road image so as not to become an unnatural image while maintaining the vertical relationship of each road.

  According to the structure of Claim 4, the hierarchy is adjusted so that the gradient of each hierarchy setting point may become below a predetermined value. Therefore, it is possible to draw the road image so that the gradient of the road image does not become an unnatural gradient while maintaining the vertical relationship of the roads.

  According to the structure of Claim 5, the height coordinate provided based on the difference of a hierarchy is provided to the shape interpolation point between each hierarchy setting point. For this reason, when displaying a road image in three dimensions, a road image can be drawn smoothly along an actual road shape.

  According to the method of claim 6, the hierarchy indicating the vertical relationship of each road is set in association with the two-dimensional coordinates of the hierarchy setting point. Moreover, the hierarchy is adjusted according to the hierarchy of the surrounding hierarchy setting point. For this reason, it is possible to reduce the amount of data stored in the device by making the information indicating the vertical relationship of the road simple, and to make the road image an image along the scenery that is actually visually recognized. it can.

  According to the method of claim 7, the level is adjusted to suppress undulations when there are a plurality of level setting points on the same road. In addition, the level of the other road in the vertical relationship at the level setting point where the undulation is suppressed is adjusted in accordance with the adjustment. For this reason, it is possible to draw a road image so as not to become an unnatural image while maintaining the vertical relationship of each road.

  According to the method of the eighth aspect, when the gradient of the hierarchy of successive hierarchy setting points on the same road is large, the hierarchy can be adjusted to reduce the gradient. Therefore, it is possible to draw the road image so that the gradient of the road image does not become an unnatural gradient while maintaining the vertical relationship of the roads.

  According to the method of Claim 9, the height coordinate given based on the difference of a hierarchy is provided to the shape interpolation point between each hierarchy setting point. For this reason, when displaying a road image in three dimensions, a road image can be drawn smoothly along an actual road shape.

According to the program of the tenth aspect, the control means acquires a hierarchy indicating the vertical relationship of each road. Moreover, the hierarchy is adjusted according to the vertical relationship between adjacent hierarchy setting points. For this reason, it is possible to reduce the amount of data stored in the device by making the information indicating the vertical relationship of the road simple, and to make the road image an image along the scenery that is actually visually recognized. it can.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, the navigation unit 2 constituting the navigation system 1 includes a main CPU 10, a RAM 11, a ROM 12, and a vehicle side interface (I / F) 13. The main CPU 10 performs various controls according to various programs such as a map drawing program stored in the ROM 12 or the like using the RAM 11 as a work area. The navigation unit 2 corresponds to a navigation device, control means, horizontal coordinate acquisition means, and hierarchy acquisition means.

  Further, the main CPU 10 inputs a position detection signal from the GPS receiver 30 via the vehicle side I / F 13 and calculates the absolute position of the host vehicle by radio wave navigation. Further, the main CPU 10 calculates the relative position of the own vehicle by autonomous navigation based on the vehicle speed sensor 31 and the gyro 32 via the vehicle side I / F 13 and specifies the own vehicle position in combination with the absolute position.

  The navigation unit 2 includes a horizontal coordinate storage unit, a hierarchical storage unit, a geographic information storage unit 15 as an interpolation data storage unit, and an image processor 18 as an image processing unit. The geographic information storage unit 15 is an auxiliary storage device such as a built-in hard disk. The geographic information storage unit 15 stores route network data (hereinafter referred to as route data) 16 for searching for a route to the destination, and map drawing data 17. The image processor 18 is an LSI or the like that executes image processing according to the main CPU 10.

  The route data 16 is data for searching for a route to a destination, and indicates roads in a mesh that divides the whole country by nodes and links. In the present embodiment, a node indicates a data element indicating a connection point or branch point with another road such as an intersection or an interchange, and an end point of the road, and a link indicates a data element that connects the above nodes. The route data 16 has a link cost corresponding to each link, and the main CPU 10 searches for a recommended route from the current location to the destination under various conditions based on the link cost.

  The map drawing data 17 is data for drawing the map screen 5a on the display 5 as the display means of the navigation system 1 by the image processor 18, and is stored for each area that divides the map of the whole country. The map is managed for each level from the map of the map to the map of the narrow area. In this navigation system 1, 2D mode for displaying the map screen 5a two-dimensionally and 3D mode for displaying the map screen 5a three-dimensionally can be selected as the map display format. The map screen 5a is displayed in accordance with a predesignated mode. In the 2D mode, the map screen 5a is displayed as if the road is looked down from directly above, but the vertical relationship of the roads that are three-dimensionally crossed is displayed in an identifiable manner. In the 3D mode, a map screen 5a viewed from a perspective obliquely above the road is displayed. In addition, each mode may be set by operating the operation button 5b adjacent to the display 5 or touch panel operation. In normal times, the map screen 5a is displayed in the 2D mode, and when approaching a specific point, You may make it switch to 3D mode automatically. Identification data indicating the set mode is temporarily stored in the RAM 11 or the like.

The map drawing data 17 has an area ID, background data, road data, and the like. The area ID indicates the identifier of the drawing target area. The background data is drawing data for drawing roads, urban areas, rivers, and the like, and includes polyline data, polygon data, text data, and the like.

  Road data is data for drawing a road, and is node data, link data, interpolation coordinate data as two-dimensional coordinates, height data as height coordinates of shape interpolation points, road type, road attribute, hierarchy Has data etc. The node data and link data are data indicating the coordinates of the nodes and links of each road included in the area. The interpolation coordinate data indicates the coordinates of each shape interpolation point set between the nodes. The shape interpolation point is set between the nodes to indicate the curve shape of the road. The coordinates of this shape interpolation point are represented by two-dimensional coordinates, as with nodes and links, and are stored as interpolation coordinate data. Further, the height data of the shape interpolation point is a coordinate in the height direction given to each shape interpolation point. This height coordinate does not indicate the absolute height of the road, but is a coordinate for smoothing a three-dimensionally drawn road image when the 3D mode is set.

The road type indicates a type such as an expressway, a national road, a prefectural road, and a general road, and the road attribute indicates a road attribute such as a road width and a traffic direction.
Further, the hierarchy data is data indicating the hierarchy of each road at the hierarchy setting point set to indicate the vertical relationship of each road, and in this embodiment, a three-dimensional intersection is set as the hierarchy setting point. Yes. As shown in FIG. 2, the hierarchical data 20 includes an intersection ID 20a, a horizontal coordinate 20b as a two-dimensional coordinate, a road identifier 20c, and a hierarchy 20d. In addition, an intersection is a point where each road is three-dimensionally crossed at different height positions, not on the same plane.

  The intersection ID 20a is an identifier of the intersection and uses a number assigned in advance. In this embodiment, in order to distinguish the level of each road at the intersection, for example, at intersection A, the intersection of the upper road is “A1” and the intersection of the lower road is “A2”, and the three-dimensional intersection is performed at the same intersection. Different identifiers are assigned to each road. The horizontal coordinate 20b is coordinate data of an intersection, and may be a distance from a node adjacent to the intersection or an absolute coordinate on a map. Further, the intersection ID 20a may be represented by a horizontal coordinate 20b. The road identifier 20c is an identifier of a road with an intersection, and is a road name, a number assigned to each road, a link ID, or the like.

  The hierarchy 20d is a discrete value indicating the vertical relationship of each road at the intersection. In the present embodiment, as the value of the hierarchy 20d, any one of “0”, “1”, “2”... “N” (N is a natural number) is stored. For this reason, the data indicating the vertical relationship of the road can be simplified without using the data indicating the absolute height in the height direction.

  In addition, when the hierarchy 20d is “0”, it indicates that the road is at the lowest position, and when it is “1” or more, it indicates that the road is above another road. Show. Therefore, it is possible to easily grasp whether or not there is another road below the road by referring to the hierarchy 20d.

  First, the hierarchy 20d given to each intersection in the initial state will be described. For example, as shown in FIG. 3, when a road 101 branched at a node N1 and a main road 102 are three-dimensionally crossed at an intersection A and the road 101 is above the main road 102, as shown in FIG. “0” is assigned to the intersection A1 set to 102 as the hierarchy 20d, and “1” is assigned to the intersection A2 of the elevated road 101 as the hierarchy. Although illustration of shape interpolation points is omitted in FIG. 3, shape interpolation points are actually set between nodes N.

Similarly, at the intersection B where the road 101 and the main road 103 intersect three-dimensionally, “0” is given to the intersection B1 of the lower main road 103, and “1” is given to the intersection B2 of the road 101. Further, at the intersection C where the road 101 and the road 103 intersect three-dimensionally, the intersection C1 of the road 103 which is the lower road
“0” is assigned to “1”, and “1” is assigned to the intersection C2 of the road 101. Furthermore, if the main road 106 connected to the road 101 via the node N2 intersects the lower general road 105 at the intersection D, the intersection D1 of the elevated main road 103 is “1”, an elevated “0” is assigned to the intersection D2 of the lower general road 105.

Furthermore, the hierarchy 20 d is set for the other intersections E to G, and the set hierarchy 20 d is stored as the hierarchy data 20.
When the 2D mode is set, the image processor 18 draws on the map screen 5a in such a manner that the vertical relationship between the three-dimensionally intersecting roads can be identified according to the respective layers 20d. On the other hand, when the 3D mode is set, the image processor 18 adjusts each layer 20d in accordance with the layer transition between the surrounding intersections. In this embodiment, the hierarchical data 20 once corrected by the image processor 18 is overwritten on the map drawing data 17 or stored in another storage unit, and in the subsequent map drawing processing, the corrected hierarchical data 20 is stored in the map drawing data 17. Used. Although the image processor 18 adjusts the hierarchy 20d here, the main CPU 10 may execute the adjustment.

  When the 3D mode is set, the image processor 18 sets an area for setting the hierarchical data 20. At this time, an area included in the predetermined distance range centered on the vehicle position may be targeted, or an area included in the predetermined distance range centered on the point designated by the user may be targeted. Or it is good also considering the mesh containing the own vehicle position or the designated point.

  Further, the image processor 18 determines whether there is a three-dimensional intersection in the area. At this time, the hierarchical data 20 having the area as the horizontal coordinate 20b may be searched to determine whether or not there is an intersection, whether or not a node is set at a location where the link intersects, If it is not set, it may be determined that it is a three-dimensional intersection. Alternatively, the presence or absence of a three-dimensional intersection may be determined by setting a flag indicating that it is a three-dimensional intersection at a node or link around the three-dimensional intersection and determining the value of the flag.

  Further, the image processor 18 determines whether or not the hierarchy 20d needs to be corrected based on the hierarchy 20d of each intersection on the same road, and if necessary, corrects the hierarchy 20d. To describe this process in detail, first, when there are continuous intersections on the same road, the image processor 18 determines whether or not the hierarchical transition of the intersection is repeated. For example, as shown in the conceptual diagram of FIG. 4, when the road 110 intersects with the roads 111 to 114 at four intersections J to M, in the initial state showing only the top and bottom of each road, each intersection J Each level 20d of ~ L is set to (J, K, L, M) = (0, 1, 0, 1) in the X-axis direction. In the present embodiment, the values of the hierarchy 20d are, for example, (0, 1, 0), (1,0, 1), and the intersections where the transition to the higher level and the transition to the lower level are continuous and the level 20d is different. When the relative distance is short, it is determined that there is a wave of the layer 20d. In other words, for example, when (0, 1, 2) is continuously transitioning to a higher layer, or (2, 1, 0) is continuously transitioning to a lower layer, Do not judge. In the case of (0, 1, 1, 0), after transitioning from “0” to “1”, transitioning to “0” via “1” which is the same hierarchy 20d, Since the transition to is not continuous with the transition to the lower class, it is not judged as wavy.

  If there is a wave of the hierarchy 20d, the road image displayed as the map screen 5a will wave and become an unnatural image when displayed on the map screen. In addition, when the relative distance of each intersection which is different in the hierarchy 20d is equal to or less than a predetermined distance, each intersection is sufficiently separated, so that a smooth road image can be drawn instead of an unnatural road image. Not performed. The predetermined distance may be an actual distance such as 1 km or a distance on a map.

  When such a road is detected, the image processor 18 corrects the hierarchy 20d of the intersection on the road 110, and also creates a hierarchy 20d of surrounding roads in accordance with the correction. That is, one of the hierarchies 20d at the intersection on the road where the undulation occurred is moved up. For example, in the case of the road 110, since the intersection point K and the intersection point L of (J, K, L, M) = (0, 1, 0, 1) are sandwiched between the intersections of the different layers 20d, The hierarchy 20d is moved up and corrected to (J, K, L, M) = (0, 1, 1, 1).

  The image processor 18 determines that another road is three-dimensionally crossed above the level 20d of the intersection L of the road 110 because it is “0” in the initial state. And based on the hierarchy data 20, the hierarchy 20d with respect to the other road above the road where the hierarchy 20d was corrected is corrected. For example, the level 20 d of the road 113 that intersects the road 110 at the intersection L is raised from “1” to “2”. As a result, as shown in FIG. 5, it is possible to perform correction to suppress the undulation of the road 110 while maintaining the vertical relationship between the road 110 and the road 113 at the intersection L. When the undulation of the road 110 is suppressed, the correction of the hierarchy 20d at each intersection is repeated until the undulation of all roads included in the set area is suppressed.

  In this way, by indicating the relative height of each three-dimensionally intersecting road as “0” or “1” in the initial state, the vertical relationship of each road can be shown simply and clearly, and The amount of height data indicating the relationship can be reduced. Further, there is a possibility that the road image becomes an unnatural image simply using the simple hierarchical data 20 as described above, but it is determined whether or not the road image is wavy and the hierarchy 20d of the intersection is moved up. Since the upper and lower road layers 20d are corrected in accordance with this correction, the road image can be made a smooth image without any sense of incongruity while maintaining the vertical relationship between the roads. Further, when the hierarchy 20d is corrected, the hierarchy 20d is simply changed to the higher hierarchy 20d, so that the correction process can be simplified.

  After suppressing the undulation of the hierarchy 20d, the image processor 18 searches for intersections that are different from each other in the hierarchy 20d among consecutive intersections on the same road, and whether there is a section where the gradient between the intersections is steep. Is judged. Normally, the gradient of the actual road is gentle around the three-dimensional intersection, but if the gradient between the intersections displayed on the map screen 5a is large, the difference from the outside scene that the user actually sees increases. Processing to suppress steep slopes.

  Specifically, as shown in FIG. 6, when there are a plurality of intersections Q and S on the road 120 and the levels 20d of the intersections Q and S are different from each other, the main CPU 10 determines the gradient G of each level 20d. Determine the size of. The gradient G is obtained by a value obtained by dividing the difference between the levels 20d of the intersections Q and S by the relative distance ΔL on the horizontal plane (XY plane) of the intersections Q and S. That is, if the values of the hierarchy 20d of the road 120 at the intersections Q and S are Cq and Cs, respectively, the gradient G = | Cq−Cs | / ΔL.

  Next, the image processor 18 compares the calculated gradient G with a predetermined value set in advance. The predetermined value is set to the minimum value when the road image looks steep when the road image is drawn on the map screen.

  When the gradient G is less than the predetermined value, the road image does not become steep, so the hierarchy 20d of each intersection Q, S is not corrected. On the other hand, when the gradient G is equal to or greater than the predetermined value, the image processor 18 moves up the hierarchy 20d of the low-level intersection S, and accordingly moves up the hierarchy 20d at the intersection S of the other road 122 that intersects the road 120.

For example, it is determined that there is a steep slope between the intersections Q-S, and the level 2 at the intersection S of the road 120 is
When 0d is “0” and the level 20d at the intersection S of the road 122 is “1”, the level 20d of the road 120 is raised from “0” to “1”, and the level 20d of the road 122 is set to “1”. Move up to "2". As a result, as shown in FIG. 7, the steep slope of the road 120 is suppressed while maintaining the vertical relationship between the roads 120 and 122.

Further, by performing this process after suppressing the undulation of the road image, it is possible to efficiently set the hierarchy 20d for suppressing the steep slope.
When the hierarchy 20d is corrected in this way, the image processor 18 sets the height data of the shape interpolation points between the intersections. For example, as shown in FIG. 8, when there is an intersection T where the hierarchy level 20d is “0” and an intersection U where “1” is present, the main CPU 10 determines the shape arranged between the intersections TU from the map drawing data 17. Interpolation coordinate data of the interpolation points P1 to Pn is acquired (n is a natural number).

  Further, the image processor 18 calculates the difference ΔC of the hierarchy 20d between the intersections TU. Further, the number N of shape interpolation points P arranged between the intersections TU is acquired, the difference ΔC of the layer 20d is divided by the number N + 1, and the interval in the height direction (Z direction) of each shape interpolation point P is obtained. ΔZ is calculated. That is, ΔZ = ΔC / (N + 1).

  Further, as the height data of each shape interpolation point P, a height N times the interval ΔZ is set in order from the side closer to the intersection T. Accordingly, the height data of the shape interpolation points P1 to Pn are ΔZ, 2 · ΔZ,... N · ΔZ in the order of P1, P2,. As a result, as shown in FIG. 8, the shape interpolation points P1 to Pn are arranged along the road shape at equal intervals in the height direction (Z direction) between the intersection points TU.

  When the height data of the shape interpolation point P is set in this way, the image processor 18 associates the height data with the interpolation coordinate data and stores it in the geographic information storage unit 15. After the corrected hierarchical data 20 and the height data of the shape interpolation point P are stored, the image processor 18 draws the map screen 5a based on the corrected data. In addition, in the corrected data, it is possible to identify whether or not the correction has been performed by setting a flag value indicating whether or not the correction has been performed to “ON”.

  Next, a processing procedure when the navigation unit 2 displays the map screen 5a will be described with reference to FIG. First, the image processor 18 of the navigation unit 2 reads out the map drawing data 17 of the area to be drawn from the geographic information storage unit 15 (step S1-1).

  Further, the image processor 18 determines whether or not there is a three-dimensional intersection in the drawing area (step S1-2). At this time, as described above, the image processor 18 determines whether or not there is a point where the hierarchical data 20 is set, or whether there is a point where no node is set at a point where the link intersects. Determine if there is an intersection.

  If it is determined that there is no three-dimensional intersection in the drawing area (NO in step S1-2), the process proceeds to step S1-5, and a depression angle for drawing the map screen 5a is set based on a preset mode. Further, drawing data is generated based on the set depression angle (step S1-6). That is, drawing data for displaying the map screen 5a is generated based on node data, link data, interpolation coordinate data, road attributes, and the like. When the drawing data is generated, the image processor 18 outputs the drawing data to the display 5 and outputs the map screen 5a (step S1-7). And it returns to S1-1 and repeats the above-mentioned process until the navigation system 1 is shut down.

On the other hand, if it is determined in step S1-2 that there is a three-dimensional intersection in the drawing area (YES in step S1-2), the image processor 18 determines whether or not the preset mode is the 3D mode. (Step S1-3). The image processor 18 determines whether or not it is in the 3D mode based on the mode identification data stored in the RAM 11 or the like, and determines that it is in the 2D mode (NO in step S1-3), the above-described steps. Proceed to S1-5.

  At this time, the image processor 18 sets the depression angle in the 2D mode, and generates drawing data based on the depression angle (step S1-6). When drawing a three-dimensional intersection, the image processor 18 generates lower road drawing data based on the hierarchical data 20 and the node data, link data, interpolation coordinate data, road attributes, and the like. Specifically, as shown in FIG. 11A, first, a belt-like first image 50 and second image 51 are superimposed to draw a lower road image R1 that is an image of the lower road. The first image 50 and the second image 51 are drawn in different colors. The width of the first image 50 is larger than the width of the second image 51. When the second image 51 is superimposed on the first image 50 with the center line aligned, the edge of the first image 50 becomes the lower road image R1. The outline is displayed.

  Furthermore, the image processor 18 draws a high-level road image as shown in FIG. That is, the image processor 18 superimposes the first image 50 constituting the upper road image R2 on the lower road image R1 and superimposes the second image 51 on the first image 50. As a result, the lower road image R1 is divided by the first image 50 that is the outline of the upper road image R2, and the vertical relationship between the upper road image R2 and the lower road image R1 can be identified.

  Furthermore, the image processor 18 draws the background image of the drawing target area based on the polygon data included in the map drawing data 17 together with the images R1 and R2. When the vehicle position is included in the area drawn on the map screen 5a, the vehicle index 5c is superimposed on the road image. Then, after temporarily storing the generated drawing data in the VRAM, the map screen 5a is output to the display 5 (step S1-7). As a result, a map screen 5a as shown in FIG. A road image R indicating each road is displayed on the map screen 5a. When the navigation unit 2 is searching for a route to the destination, the route index 5d is superimposed on the road image. When the route searched by the navigation unit 2 includes a road on the lower side at the three-dimensional intersection, a part of the route index 5d is blocked by the upper road image R on the map screen 5a. For this reason, since the user can immediately determine that the route is a lower road, the user is not lost.

  For example, when the host vehicle travels on the lower road at a three-dimensional intersection and reaches the lower side of the upper road, the image processor 18 determines whether the lower road image R and the upper road image R are Since the own vehicle index 5c is superimposed, at least a part of the own vehicle index 5c is shielded by the upper road image R as shown in FIG. For this reason, the user can discriminate the road on which the vehicle is traveling among the three-dimensionally intersecting roads, and does not feel a sense of incongruity with the actually viewed outside scene.

  On the other hand, when the 3D mode is set in step S1-3 (YES in step S1-3), the image processor 18 performs a hierarchy setting process (step S1-4). This hierarchy setting process will be described with reference to FIG.

In the hierarchy setting process, the image processor 18 acquires the horizontal coordinates 20b of all the intersections in the area based on the hierarchy data 20 (step S2-1). Further, the image processor 18 determines whether the hierarchical data 20 in the area is data corrected in the past by referring to a flag associated with the hierarchical data 20 (step S2-2). If the data has been corrected in the past (NO in step S2-2), since the hierarchical data 20 and the like are corrected for each area in this embodiment, it is determined that the area has been corrected. Then, the hierarchy setting process is terminated, and the process proceeds to step S1-5.

  If the data has not been corrected in the past (YES in step S2-2), the image processor 18 determines whether there is a wave on the same road (step S2-3). If it is determined that there is no undulation (NO in step S2-3), the process proceeds to step S2-5 described later.

  On the other hand, if it is determined in step S2-3 that there are undulations on the same road (YES in step S2-3), the image processor 18 aligns the hierarchy 20d of the intersections on the same road as described above (step S2-4). ). That is, the hierarchy 20d of any intersection is raised among the intersections in the section with undulations. Accordingly, it is determined whether or not it is necessary to change the level 20d of another road that is three-dimensionally crossed at the intersection where the level 20d is advanced, and if it is necessary to change, the level 20d is changed.

  Further, the image processor 18 determines whether or not there is a steep slope between the intersections (step S2-5). If it is determined that there is no steep slope (NO in step S2-5), the process proceeds to step S2-7. If it is determined that there is a steep slope (YES in step S2-5), the intersection hierarchy 20d is adjusted as described above (step S2-6). That is, it is determined whether it is necessary to move up the level 20d of any intersection and to raise the level 20d of another road that intersects at that intersection. When it is necessary to move up, the level 20d of the road is moved up, and when it is not necessary, the level 20d is maintained.

  When the hierarchy 20d is adjusted, the image processor 18 acquires the interpolation coordinate data, adjusts the height of the shape interpolation point P between the intersections as described above (step S2-7), and proceeds to step S2-8. move on. In step S2-8, it is determined whether or not the setting of the hierarchy 20d has been completed for all intersections in the designated area. If completed (YES in step S2-8), the hierarchy setting process in the area is terminated, and the process returns to step S1-5. If the setting of the hierarchy 20d has not been completed for all the intersections in the designated area (NO in step S2-8), the process returns to step S2-3.

  In step S1-5 shown in FIG. 9, the image processor 18 sets the depression angle corresponding to the preset 3D mode as the depression angle when drawing the map screen 5a. Further, the image processor 18 generates drawing data based on the depression angle (step S1-6). When rendering a three-dimensional intersection, the image processor 18 superimposes the upper road image R2 on the lower road image R1, as shown in FIG. Furthermore, drawing data of the background image is generated, and image processing such as a central projection method is performed on the road image and the background image, and the drawing data is converted into drawing data viewed from an obliquely upper viewpoint with respect to the horizontal plane. At this time, image processing for drawing a three-dimensional image such as shading, shadowing for drawing a shadow of the upper road, and hidden surface removal may be performed.

  As a result, as shown in FIG. 14, a map screen 5 a overlooking the road from obliquely above is displayed on the display 5. In this map screen 5a, since the intersection level 20d is corrected according to the road shape in the height direction, the road image is drawn in a state where there is no undulation and an unnatural steep slope is suppressed. For this reason, when the user visually recognizes the scenery outside the vehicle and compares it with the map screen 5a, it is possible to prevent the map screen 5a from feeling uncomfortable. Moreover, since the shape interpolation point is set between the intersections, the difference from the road shape that is actually visually recognized can be reduced.

When the map screen 5a is displayed on the display 5, the process returns to step S1-1, and the image processor 18 repeats the above processing until the navigation system 1 is shut down.

According to the above embodiment, the following effects can be obtained.
(1) In the above embodiment, the navigation unit 2 stores the horizontal coordinate 20b of the three-dimensional intersection point in the map drawing data 17 for indicating the vertical relationship of each road. Further, the map drawing data 17 includes hierarchical data 20 indicating the vertical relationship of each road at a three-dimensional intersection (intersection). In addition, the hierarchy 20d of the hierarchy data 20 is corrected according to the change in the hierarchy 20d at the adjacent intersection, and the other road hierarchy 20d associated with the hierarchy 20d is also corrected. The navigation unit 2 uses the map drawing data 17 to display the road vertical relationship at the intersection so as to be identifiable. For this reason, the hierarchical data 20 indicating the vertical relationship of the road can be simplified relative data compared to the absolute height data of each point on the road. Moreover, the labor at the time of creating the map drawing data 17 can be reduced. Furthermore, the amount of data stored in the navigation unit 2 can be reduced, and the load during map drawing processing can be reduced. Further, by adjusting the layer 20d, the road image displayed on the map screen 5a can be made to be an image along the scenery that is actually visually recognized.

  (2) In the above embodiment, the hierarchy data 20 is modified such that when there are a plurality of continuous intersections on the same road, the hierarchy 20d that suppresses the undulation in which the hierarchy 20d for each intersection continuously fluctuates. Yes. In addition, with the correction of the level 20d, the level 20d for the other road that is in a vertical relationship at the intersection is also corrected. Therefore, when the navigation unit 2 draws the map screen 5a using the map drawing data 17, the road image can be displayed so as not to become an unnatural image while maintaining the vertical relationship of each road.

  (3) In the above-described embodiment, the hierarchical data 20 includes a hierarchy of one road according to the gradient magnitude of each hierarchy 20d when different levels 20d are set at successive intersections on the same road. 20d is corrected, and the hierarchy 20d for the other road that is in a vertical relationship at the intersection is corrected along with the correction for the intersection. For this reason, when the navigation unit 2 draws the map screen 5a using the map drawing data 17, the road image is prevented from being drawn with an unnatural steep slope while maintaining the vertical relationship of each road. it can.

  (4) In the above embodiment, the two-dimensional coordinates of the shape interpolation point P set between successive intersections of the same road and the interval ΔZ obtained by equally dividing the difference ΔC of each layer 20d of each intersection are associated with the geography. The information is stored in the information storage unit 15. Further, the image processor 18 draws a road shape based on the height data of the shape interpolation point P. For this reason, when the 3D mode is set, the road image R can be smoothly drawn in the height direction along the actual road shape. Further, since the height data is given to each shape interpolation point P based on the interval ΔZ obtained by equally dividing the difference ΔC, the height data can be easily given to the shape interpolation point P.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. Note that the second embodiment has a configuration in which only the first embodiment is changed, and thus detailed description of the same parts is omitted.

  In the present embodiment, the relative heights of the hierarchical data 20 and the shape interpolation point P in the initial state are corrected in advance, and the corrected hierarchical data 20 and the relative height of the shape interpolation point P are stored in the navigation unit 2. The navigation unit 2 draws the map screen 5a based on the corrected hierarchical data 20 and the shape interpolation point P.

A method for setting the relative height of the hierarchical data 20 and the shape interpolation point P will be described. The relative heights of the hierarchical data 20 and the shape interpolation point P are set using a data creation terminal 40 that creates the map drawing data 17. As shown in FIG. 15, the data creation terminal 40 includes a CPU 41, a RAM 42, a ROM 43, an image processor 44, and a creation data storage unit 45, and is connected to an input device 46 such as a mouse and a keyboard and a display 47. . The creation data storage unit 45 stores map drawing data 17.

  The setting process of the hierarchical data 20 will be described with reference to FIG. The area for setting the hierarchical data 20 is designated by the data creation terminal 40 (step S3-1). When the area is designated, it is determined whether or not a three-dimensional intersection is included in this area (step S3-2). At this time, it is determined whether or not a node is set at the intersection of the links. If there is no solid intersection (NO in step S3-2), the process for that area is terminated, and the process returns to step S3-1 to perform the process for the next area.

  If there is a three-dimensional intersection in the designated area (YES in step S3-2), the intersection is set at a point where the link intersects the link and no node is set (step S3-3). That is, the intersection ID 20 a is assigned to the intersection between the links, and the horizontal coordinate 20 b is acquired and registered as the hierarchical data 20.

  Furthermore, the initial level 20d is set at each intersection (step S3-4). Specifically, “1” is assigned to the intersection of the upper road, and “0” is assigned to the intersection of the lower road. Further, it is determined whether or not there is a wave on the same road (step S3-5). Here, the presence / absence of road undulations is determined in the same manner as in step S2-3.

  If there is no undulation (YES in step S3-5), the process proceeds to step S3-6. If it is determined that there is a wave (NO in step S3-5), the process returns to step S3-4, and the layers are arranged in the same manner as in step S2-4 described above. And step S3-4-step S3-5 are repeated until there is no waviness.

  In step S3-6, whether or not there is a steep slope between the intersections is determined as in step S2-5. If it is determined that there is no steep slope (YES in step S3-6), the process proceeds to step S3-7. If there is a steep slope (NO in step S3-6), the process returns to step S3-4, and the hierarchy 20d is adjusted in the same manner as in step S2-6 described above. Then, steps S3-4 to S3-6 are repeated until there is no steep slope. When the undulation and the steep slope disappear, the process proceeds to step S3-7.

  In step S3-7, as in step S2-7, the height of the shape interpolation point P arranged between the intersections is set. Then, the hierarchical data 20 is registered in the map drawing data 17 of the created data storage unit 45 (step S3-8), and the height of the shape interpolation point P is registered (step S3-9).

  The map drawing data 17 in which the corrected hierarchical data 20 and the relative height of the interpolation points are registered is stored in the navigation unit 2. Alternatively, the map drawing data 17 before correction may be stored in the navigation unit 2 in advance, and the corrected hierarchy data 20 and the relative height of the interpolation points may be overwritten on the map drawing data 17. As a data transmission method to the navigation unit 2, the data creation terminal 40 may distribute the hierarchical data 20 and the height of the interpolation point to the navigation unit 2 mounted on the vehicle via the network. You may make it store beforehand when the navigation unit 2 is mounted in a vehicle. Alternatively, the map drawing data 17 may be stored in a storage medium such as an optical disk, and the storage medium may be inserted into the navigation system 1 so that the navigation unit 2 overwrites the geographic information storage unit 15. In this way, the load on the navigation system 1 can be reduced by correcting the height of the hierarchical data 20 and the interpolation points in advance.

Therefore, according to the second embodiment, the following effects can be obtained in addition to the effects described in the first embodiment.
(5) In the second embodiment, the relative heights of the hierarchical data 20 and the interpolation points in the initial state are corrected in advance, and the corrected hierarchical data 20 and the relative heights of the interpolation points are registered in the navigation unit 2. For this reason, since the navigation unit 2 can omit the correction processing of the relative height of the hierarchical data 20 and the interpolation point, it is possible to reduce the load applied when the map is drawn.

In addition, you may change the said embodiment as follows.
In the above embodiment, “waved” is a continuous change of the layer 20d, but the number of repetitions of layer transition as a reference when determining the waved may be other than two. For example, when it changes continuously three times or more like (0, 1, 0, 1), it may be determined that there is a wave.

  In the above embodiment, the initial level 20d is set to “0” or “1”, but other levels 20d (2, 3,... N) may be added. Further, in this case, when there is a wave of hierarchy transition, the hierarchy 20d in the initial state may be raised or lowered.

  In the above embodiment, when the road image is drawn, the upper road image R2 is superimposed on the lower road image R1, but other drawing methods may be used. For example, image processing such as hidden surface removal may be performed based on the hierarchy 20d.

  In the above-described embodiment, the case where the hierarchy setting point is a three-dimensional intersection is described, but any other point may be used as long as it is a point for drawing the vertical relationship of the road. For example, you may set a hierarchy setting point in the area where each road extends in parallel.

The block diagram of the navigation system of this embodiment. The conceptual diagram explaining the data structure of hierarchical data. The conceptual diagram of a three-dimensional intersection. The conceptual diagram explaining the hierarchy set on the road. Conceptual diagram of hierarchy correction. The conceptual diagram explaining the gradient between hierarchy. The conceptual diagram explaining correction of a gradient. The conceptual diagram explaining the process which sets a relative height to a shape interpolation point. The flowchart explaining the process sequence of 1st Embodiment. The flowchart which shows the process sequence of a hierarchy setting process. It is explanatory drawing explaining the drawing process of the road which carried out three-dimensional intersection, Comprising: (a) is a lower side road image, (b) is the state which superimposed the 1st image, (c) shows the state which superimposed the upper road image. . The screen figure of 2D mode. The screen figure of 2D mode. The screen figure of 3D mode. The block diagram of the data creation terminal of 2nd Embodiment. The flowchart explaining the process sequence of 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Navigation system, 2 ... Navigation apparatus, Control means, Horizontal coordinate acquisition means, Navigation unit as hierarchy acquisition means, 5 ... Display as display means, 5a ... Map screen, 15 ... Horizontal coordinate storage means, Hierarchy storage means, Geographic information storage unit as interpolation data storage means, 17 ... map drawing data, 18 ... image processor as image processing means, 20b ... horizontal coordinates as two-dimensional coordinates, 20d ... hierarchy, 101, 103, 110, 111 to 115 , 120 to 122 ... road, G ... gradient, P, P1 to Pn ... shape interpolation point, ΔC ... difference.

Claims (10)

In the drawing data creation method for creating map drawing data,
Set a hierarchy setting point that indicates the vertical relationship of each road,
Each level indicating the vertical relationship of each road at the level setting point is adjusted according to the level transition between the level setting point and the surrounding level setting point, and each level is adjusted to a two-dimensional coordinate of the level setting point. A drawing data creation method characterized by registering in association with the. In a navigation device that displays a map screen on a display means,
Horizontal coordinate storage means for storing the two-dimensional coordinates of the hierarchy setting points set to indicate the vertical relationship of each road;
A hierarchy storage means for adjusting each hierarchy indicating the upper and lower relations of each road at the hierarchy setting point according to a hierarchy transition with the surrounding hierarchy setting points and storing for each road;
Image processing means for recognizing the upper and lower relations of the roads at the hierarchical setting points based on the two-dimensional coordinates of the hierarchical setting points and the hierarchical levels set for the roads; A navigation device characterized by comprising: The navigation device according to claim 2, wherein
The hierarchy is adjusted to suppress the undulation of the hierarchy with respect to the hierarchy setting point when there is the hierarchy setting point continuous on the same road,
In accordance with the adjustment to the level setting point, the level of the other road on the upper side or the lower side at the level setting point that has been adjusted is adjusted. The navigation device according to claim 3,
The navigation apparatus according to claim 1, wherein the hierarchy is adjusted to a hierarchy in which a slope of each successive hierarchy setting point on the same road is less than a predetermined value. In the navigation device according to any one of claims 2 to 4,
The two-dimensional coordinates of the shape interpolation points set between the respective hierarchical setting points on the same road, and the height coordinates of the respective geometric interpolation points given based on the differences of the respective hierarchical levels of the respective hierarchical setting points; Is further provided with interpolation data storage means for storing
The navigation apparatus characterized in that the image processing means draws a road shape based on a height coordinate of the shape interpolation point. In a map drawing method for displaying a map screen on a display means,
The two-dimensional coordinates of the hierarchy setting point set to indicate the vertical relationship of each road and each hierarchy indicating the vertical relationship of each road at the hierarchy setting point are set in association with each road, Each level at the level setting point is adjusted according to the level transition between the level setting points around it and set for the two-dimensional coordinates and the roads set at the level setting point. A map drawing method, characterized in that, based on each of the above-described hierarchies, the upper and lower relations of each road at the hierarchy setting point are drawn in an identifiable manner. The map drawing method according to claim 6,
When there is a continuous set of each level on the same road, an adjustment is made to suppress the undulation of the level with respect to the level set point. A map drawing method comprising adjusting the hierarchy for the other road in the road. The map drawing method according to claim 7,
When different levels are set for each successive level setting point on the same road, the level of one road at the level setting point is adjusted according to the slope of the level. A map drawing method comprising adjusting the hierarchy for the other road that is vertically related at the hierarchy setting point in accordance with the adjustment for the hierarchy setting point. In the map drawing method according to any one of claims 6 to 8,
Giving the shape interpolation points set between the respective hierarchical setting points on the same road, the height coordinates of the respective geometric interpolation points based on the differences of the respective hierarchical setting points of the respective hierarchical setting points, A map drawing method characterized in that a road shape is drawn based on the height coordinates of the map. In the map drawing program for outputting the map screen to the display means using the control means for drawing the map,
The control means;
Horizontal coordinate acquisition means for acquiring the two-dimensional coordinates of the hierarchy setting point set to indicate the vertical relationship of each road;
A hierarchy acquisition means for acquiring a hierarchy adjusted in accordance with a hierarchy transition between the hierarchy setting points around the hierarchy setting points indicating the vertical relationship of the roads at the hierarchy setting points;
As image processing means for drawing the upper and lower relations of the roads at the hierarchy setting points in an identifiable manner based on the two-dimensional coordinates of the hierarchy setting points and the respective levels set for the roads. A map drawing program characterized by functioning.

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