JP3460488B2 - Navigation system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle-mounted or portable navigation system, and more particularly to a navigation system for displaying topographical information and map information in a stereoscopic bird's-eye view.

[0002]

2. Description of the Related Art Conventionally, as a vehicle-mounted or portable navigation system, one described in Japanese Patent Application Laid-Open No. 7-220055, which describes the invention of the applicant of the present application, is known. This conventional navigation system uses a GPS (Global Positioning S).
system) or the self-contained navigation system to detect the current position of the user and specify the detected current position, or specify a specific position using the keyboard or remote controller to determine the display reference point The viewpoint coordinates and the line-of-sight direction are calculated based on the traveling direction, and perspective projection conversion is performed on the map data registered in the external storage device to display the bird's-eye view as shown in FIG. 25 on the display.

[0003]

In such a conventional navigation system, detailed (large-scale) map information is displayed and displayed in an area near a certain display reference point such as the current position of the user. There is an advantage that it is possible to intuitively grasp the road condition up to a distant place by displaying the map information in which the display area expands (the scale is small) as the distance from the reference point increases.

However, in such conventional route guidance, the map data to be used is basically described in a two-dimensional coordinate system, and the ground that is the background of the map is regarded as a flat surface and displayed. Therefore, the actual ground will be displayed as a flat surface even when displaying the location of terrain with a lot of undulations, especially when displaying the user's current position as the display reference point, which is in agreement with the surrounding real landscape. Without doing so, there was a problem that there was a sense of discomfort in checking the current position on the map and grasping the relationship with the surrounding environment.

Various types of simulation software and game software exist as application software for displaying a three-dimensional model of the terrain, but the displayed terrain does not display information such as road information and place names necessary for route guidance. It cannot be used for a navigation system because the area is limited, or because it only displays a fictitious world unrelated to the actual topography.

In view of such conventional problems, three-dimensional terrain is displayed using elevation data based on the actual terrain, and map display elements such as roads and place names are arranged on the terrain. The present inventors have developed a navigation system capable of displaying a three-dimensional road map that closely resembles the actual terrain by creating and displaying a three-dimensional map.

The present invention relates to a navigation system having a series of three-dimensional map display functions of the present invention, the purpose of which is to hide a display reference point such as the position of a vehicle in a high mountain on the front side from the viewpoint. It is an object of the present invention to provide a navigation system in which the display reference point can be always displayed without being hidden and the position of the own vehicle can always be accurately grasped even when traveling in such a deep mountain area.

[0008]

A navigation system according to a first aspect of the present invention comprises a terrain data storage means for storing terrain shape data capable of giving elevation values to terrain plane coordinates, and a map such as roads and place names. Map data storage means for storing position information and incidental information of map display elements displayed above, and display reference points for inputting position coordinates and line-of-sight direction angles for determining the position and direction of the displayed map. Etc. input means and display target area determination for determining a target area (display target area) on the map displayed on the screen according to the display reference point position coordinates and the line-of-sight direction angle input from the display reference point etc. input means Means and the display target area determined by the display target area determining means,
The altitude change area determining means for determining an altitude change area according to a preset rule in the relationship between the input display reference point and the line-of-sight angle, and the display target area determined by the display target area determining means. The terrain shape data of the sampling point to which it belongs is read from the terrain data storage means, and the terrain shape modeling means for modeling the terrain shape using the terrain shape data, and the display reference points input from the input means such as the display reference points. It belongs to a display reference point elevation determining means for determining the elevation value of the display reference point from the position coordinates and the topographic shape model obtained by the topographic shape modeling means, and belongs to the elevation changing area determined by the elevation changing area determining means. Regarding the sampling points, the corresponding topographic shapes modeled by the topographical modeling means are applicable. Input the above-mentioned display reference point and the topographic shape elevation changing means for changing the elevation value of the point closer to the elevation value of the display reference point determined by the display reference point elevation determining means and remodeling the topographic shape. Viewpoint coordinate determining means for determining the viewpoint coordinates of perspective projection conversion from the display reference point position coordinates and the line-of-sight direction angle input from the means, and the display reference point elevation value determined by the display reference point elevation determining means; The map display element corresponding to the display target area is read from the map data storage means, and if necessary, the elevation value of each map display element is determined based on the topographic shape model remodeled by the topographic shape elevation changing means. , Map element elevation determining means for creating display graphic data, viewpoint coordinates determined by the viewpoint coordinate determining means, and input from the display reference point etc. input means Coordinate conversion means for performing perspective projection conversion of the terrain shape model and the map display element for which the elevation value is determined based on the line-of-sight direction angle, and the data based on the perspective projection conversion data by the coordinate conversion means. It is provided with drawing processing means for drawing a stereoscopic map image of the display target area and image display means for displaying the stereoscopic map image.

According to a second aspect of the present invention, in the navigation system according to the first aspect, the drawing processing means draws the data obtained by perspective projection conversion of the coordinate conversion means while performing hidden surface removal. .

According to a third aspect of the present invention, in the navigation system according to the first or second aspect, the drawing processing means includes:
The guide route is drawn in a drawing color or line type different from that of an ordinary road.

According to a fourth aspect of the present invention, in the navigation system according to the first to third aspects, when the drawing processing means draws the terrain shape, the drawing color is changed according to the elevation value of the terrain, and the terrain is also changed. Even when the shape is remodeled by changing the elevation value, the drawing color is changed according to the elevation value before the change.

A navigation system according to a fifth aspect of the present invention is a terrain data storage means for storing terrain shape data capable of giving elevation values to terrain plane coordinates, and a map display for displaying on a map such as roads and place names. Map data storage means for storing position information and auxiliary information of elements, display reference point position input means for inputting position coordinates and line-of-sight direction angle for determining position and direction of displayed map, and Display target area determining means for determining a target area (display target area) on the map displayed on the screen according to the display reference point position coordinates and the line-of-sight direction angle input from the display reference point etc. input means, and the display target. For the display target area determined by the area determination means, a rule set in advance in accordance with the relationship between the input display reference point and the viewing direction angle is adopted. And an elevation change area determining means for determining an elevation change area, and a sampling point group of a predetermined density is set in the display target area determined by the display target area determining means, and plane coordinates (x, y) of each sampling point are set. , The corresponding elevation value z is read from the topographical data storage means to generate a three-dimensional sampling point (x, y, z) group,
Terrain shape modeling means for creating a polyhedral shape terrain shape model by connecting the three-dimensional sampling point groups with ridges according to a predetermined rule, and display reference point position input from the display reference point input means. Display reference point elevation determining means for determining the elevation value of the display reference point from the coordinates and the topographic shape model obtained by the topographic shape modeling means, and display reference point position coordinates input from the display reference point input means. And a viewpoint coordinate determining means for determining viewpoint coordinates for perspective projection conversion from the line-of-sight direction angle and the display reference point elevation value determined by the display reference point elevation determining means, and the altitude determined by the altitude changing area determining means. The sampling points belonging to the changed area are the corresponding topographic shapes modeled by the topographical modeling means. Input the above-mentioned display reference point and the topographic shape elevation changing means for changing the elevation value of the point closer to the elevation value of the display reference point determined by the display reference point elevation determining means and remodeling the topographic shape. The display reference point position coordinates and the line-of-sight direction angle input from the means, and the map display element corresponding to the display target area are read from the map data storage means, and remodeled by the topographical shape elevation changing means as necessary. The map element elevation determining means for determining the elevation value of each map display element based on the topographical shape model and creating display graphic data, the viewpoint coordinates determined by the viewpoint coordinate determining means, the display reference point, etc. Coordinate conversion means for performing perspective projection conversion of the terrain shape model and the map display element for which the elevation value has been determined based on the line-of-sight direction angle input from the input means. The polyhedron showing a perspective projection converted terrain shape by the coordinate transformation means, and drawn by overwriting from the plane of the inner part relative to the viewpoint, and terrain shape drawing processing means for outputting a stereoscopic map image,
Based on the comparison result of the map element elevation comparison means for comparing the elevation value of the display position of each map display element determined by the map element elevation determination means and the elevation value of the corresponding terrain shape, and the map element elevation comparison means A map element drawing processing unit that draws the map display element by overwriting the corresponding topographic shape with an altitude value equal to or larger than the corresponding topographic shape; and a stereoscopic map image from the topographic shape drawing processing unit. An image display unit for displaying a composite image with the map element image from the map element drawing processing unit.

According to a sixth aspect of the present invention, in the navigation system according to the fifth aspect, the map element elevation comparing means comprises:
The elevation value of each display position of the map display elements and the elevation value of the corresponding terrain shape are compared based on the terrain drawing color.

According to a seventh aspect of the present invention, in the navigation system according to the fifth or sixth aspect, when the map element drawing processing means is a guide route and the map display element is a normal road. The drawing color or line type is different from the drawing color.

According to an eighth aspect of the present invention, in the navigation system according to the fifth to seventh aspects, when the terrain shape drawing processing unit draws the terrain shape, the drawing color is changed according to an elevation value of the terrain, Moreover, even when the terrain shape is remodeled by changing the elevation value, the drawing color is changed according to the elevation value before the change.

According to a ninth aspect of the present invention, there is provided a navigation system in which a terrain data storage means for storing terrain shape data capable of giving an elevation value to a terrain plane coordinate and a line figure such as a road, a river or a railroad map. Line graphic data storage means for storing position information and incidental information displayed above,
Location information and incidental information that displays character strings such as place names,
Or, a position name for storing position information and additional information for displaying a surface figure represented by a polygon such as a background, background data storage means, and display reference point position coordinates for determining the position and direction of the displayed map. And a display reference point etc. inputting means for inputting the line-of-sight direction angle, and a target area on the map displayed on the screen in accordance with the display reference point position coordinates and the line-of-sight direction angle inputted from the display reference point etc. Display target area determining means for determining (target area), and the display target area determined by the display target area determining means,
Within the display target area determined by the altitude change area determining means for determining the altitude change area according to a rule set in advance in the relationship between the input display reference point and the line-of-sight direction angle, and the display target area determining means. A sampling point group having a predetermined density is set, and the elevation value z corresponding to the plane coordinates (x, y) of each sampling point is read from the topographical data storage means and the three-dimensional sampling point (x, y,
z) A group of terrain shape modeling means for creating a group and creating a terrain shape model of a polyhedron shape opened by connecting the group of three-dimensional sampling points with ridge lines according to a predetermined rule, and the input means such as the display reference points. Display reference point elevation determining means for determining the elevation value of the display reference point from the input display reference point position coordinates and the topographic shape model obtained by the topographic shape modeling means, and the elevation change area determining means. For the sampling points belonging to the altitude change area, the altitude value of the corresponding point of the terrain shape modeled by the terrain shape modeling means is brought closer to the altitude value of the display reference point determined by the display reference point altitude determination means. Topography changing means for remodeling the topography, and inputting the display reference points, etc. Viewpoint coordinates determining means for determining viewpoint coordinates for perspective projection transformation from the display reference point position coordinates and line-of-sight direction angles input from the display reference point elevation value determined by the display reference point elevation determining means, and the line. The line graphic data corresponding to the display target area is read from the graphic data storage means, the place name and the background data are read from the place name and background data storage means, and remodeled by the topography shape elevation changing means as necessary. A map element elevation determining means for determining the elevation value of each line figure, a display point such as a place name and each surface figure based on the topographical shape model, and creating display figure data, and the viewpoint determined by the viewpoint coordinate determining means. Based on the coordinates and the line-of-sight direction angle input from the input means such as the display reference point, the terrain shape model and each map display element of which the altitude value is determined Coordinate conversion means for performing perspective projection conversion with the figure data for display, and of the data perspective-transformed by the coordinate conversion means, topographical data, place names, and background data are drawn while performing hidden surface removal, and a three-dimensional map image is drawn. A hidden surface removal drawing processing means for outputting
Comparison between the line figure data elevation comparing means for comparing the elevation value of the end point of each line element of the line figure data determined by the map element elevation determining means with the elevation value of the corresponding topographical shape, and the line figure data elevation comparing means Based on the result, line figure data drawing processing means for drawing by overwriting on the terrain shape for those where the elevation value of the end point of the line element of the line figure is equal to or higher than the corresponding terrain shape. Image display means for combining and displaying the stereoscopic map image from the hidden surface removal drawing processing means and the line figure image from the line figure data drawing processing means is provided.

According to a tenth aspect of the present invention, in the navigation system according to the ninth aspect, the map element elevation comparing means uses the elevation value of the terrain shape corresponding to the elevation value of the display position of each of the map display elements as the terrain drawing color. The comparison is based on this.

The invention of claim 11 relates to claim 9 or 10.
In the navigation system described above, when the line figure is a guide route, the line figure data drawing processing means draws with a different drawing color or a different line type than when the line figure is a normal road. It was done.

According to a twelfth aspect of the present invention, in the navigation system according to any one of the first to eleventh aspects, the viewpoint coordinate determining means determines the elevation coordinate of the viewpoint coordinate according to the display reference point elevation value determined by the display reference point elevation determining means. The value is changed.

According to a thirteenth aspect of the present invention, in the navigation system according to the first to the twelfth aspects, the elevation change area determining means sees the display target area determined by the display target area determining means from the viewpoint. A certain area on the near side including the display reference point is determined as the altitude change area.

According to a fourteenth aspect of the present invention, in the navigation system according to any one of the first to twelfth aspects, the elevation change area determining means surrounds the display reference point with respect to the display target area determined by the display target area determining means. The constant circular area is determined as the altitude changing area.

According to a fifteenth aspect of the present invention, in the navigation system according to the first to fourteenth aspects, the terrain shape elevation changing means sets the elevation value (hp) of the display reference point determined by the display reference point elevation determining means. On the other hand, the elevation value (denoted as h) of each sampling point belonging to the elevation change area calculated by the terrain shape modeling means is changed based on the following equation to obtain a new elevation value h. It is a thing.

H ← (h-hp) × α + hp where
1> α ≧ 0.

According to a sixteenth aspect of the present invention, in the navigation system according to the ninth to fifteenth aspects, when the hidden surface erasing drawing processing means draws the terrain shape, the drawing color is changed according to an elevation value of the terrain. Moreover, even when the terrain shape is remodeled by changing the elevation value, the drawing color is changed according to the elevation value before the change.

According to a seventeenth aspect of the present invention, in the navigation system, a terrain data storage means for storing terrain shape data capable of giving elevation values to the terrain plane coordinates and a map display for displaying on a map such as roads and place names. Map data storage means for storing position information and auxiliary information of elements, display reference point position input means for inputting position coordinates and line-of-sight direction angle for determining position and direction of displayed map, and Display target area determining means for determining a target area (display target area) on the map displayed on the screen according to the display reference point position coordinates and the line-of-sight direction angle input from the display reference point etc. input means, and the display target. For the display target area determined by the area determining means, a rule set in advance is set in accordance with the relationship between the input display reference point and the line-of-sight direction angle. Therefore, the plane / stereoscopic display area determining means for determining the plane display area and the stereoscopic display area, and the topographical data storage means for storing the topographical shape data of the sampling points belonging to the display target area determined by the display target area determining means. Topographical shape modeling means that reads from the topographical shape data and models the topography using this topographical shape data, display reference point position coordinates input from the display reference point input means, and the topography obtained by the topographical shape modeling means. Display reference point elevation determining means for determining the elevation value of the display reference point from the shape model, the display reference point position coordinates and the line-of-sight direction angle input from the display reference point input means,
Viewpoint coordinate determining means for determining perspective coordinates for perspective projection conversion from the display reference point elevation value determined by the display reference point elevation determining means, and the plane / stereoscopic display area determining means from the map data storage means. The map display element corresponding to the stereoscopic display area is read, and if necessary, the elevation value of each map display element is determined based on the terrain shape model modeled by the terrain shape modeling means, and the graphic data for stereoscopic display is obtained. The map element elevation determining means to be created and the map element corresponding to the flat display area determined by the flat / stereoscopic display area determining means are read from the map data storing means, and the display determined by the display reference point elevation determining means. Set the elevation value that is almost equal to the reference point elevation value to the elevation value of the map display element to create the plane display graphic data. Stereoscopic display in which the terrain shape model and the elevation value are determined based on the elevation value setting means, the viewpoint coordinates determined by the viewpoint coordinate determination means, and the line-of-sight direction angle input from the display reference point etc. input means. Coordinate transformation means for performing perspective projection transformation of the graphic data for use, three-dimensional map drawing processing means for rendering a three-dimensional map image of the display target area based on the data subjected to perspective projection transformation by the coordinate transformation means, and the constant elevation value. With respect to the plane display graphic data created by the setting means, the plane bird's-eye view drawing processing means for overwriting the drawn image by the three-dimensional map drawing processing means and the three-dimensional map drawing processing means to display the plane bird's-eye view at the constant elevation value. Image display means for displaying a stereoscopic map image and the plane bird's-eye view map image by the plane bird's-eye view drawing processing means A.

According to the eighteenth aspect of the present invention, in the navigation system of the seventeenth aspect, image clipping of a boundary portion between the stereoscopic map image by the stereoscopic map drawing processing means and the plane bird's-eye view map image by the plane bird's-eye view drawing processing means is further performed. An image clipping means is provided.

The invention of claim 19 relates to claim 17 or 1.
In the navigation system of No. 8, both the three-dimensional map drawing processing means and the plan bird's-eye view drawing processing means draw the guide route in a drawing color or line type different from that of an ordinary road.

According to a twentieth aspect of the present invention, in the navigation system according to the seventeenth to nineteenth aspects, the plane / stereoscopic display area determining unit views the display target area determined by the display target area determining unit from the viewpoint. The fixed front side area including the display reference point is determined as a flat display area, and the area on the rear side is determined as a stereoscopic display area.

According to a twenty-first aspect of the present invention, in the navigation system according to the seventeenth to nineteenth aspects, the plane / stereoscopic display area determining means determines the display reference point with respect to the display target area determined by the display target area determining means. The constant circular area surrounding the area is determined as the flat display area, and the other areas are determined as the stereoscopic display area.

According to a twenty-second aspect of the invention, in the navigation system according to the seventeenth to twenty-first aspects, the plane bird's-eye view drawing processing means draws the plane display area according to the elevation value of the original topographical shape. The drawing color of the area is changed.

[0031]

[0032]

[0033]

[0034]

In the navigation system according to the first and second aspects of the present invention, the topographical shape data capable of giving elevation values to the topographical plane coordinates to the external storage means and the map display to be displayed on the map such as roads and place names. The map data storing the positional information and the incidental information of the elements is stored in advance.

When it becomes necessary to display a road map for route guidance, the display reference point position coordinates and the line-of-sight direction angle are input by the display reference point input means, and the display target area determination means is displayed on the screen. The target area on the map to be displayed (display target area) is determined, and the altitude change area determination means further determines the relationship between the input display reference point and the line-of-sight direction angle with respect to the determined display target area. The altitude change area is determined according to the rule set in advance.

The terrain shape modeling means reads the terrain shape data corresponding to the display target area from the terrain data storage means and models the terrain shape.

Further, the display reference point elevation determining means determines the elevation value of the display reference point from the input display reference point position coordinates and the terrain shape model, and the viewpoint coordinate determining means determines the display reference point position coordinates and the line-of-sight direction. The viewpoint coordinates of perspective projection conversion are determined from the angle and the display reference point elevation value. Further, the terrain shape elevation changing means changes the elevation value of the corresponding point in the terrain shape model to the elevation value of the display reference point for the sampling points belonging to the elevation changing area determined by the elevation changing area determining means, and changes the terrain shape. Remodel the model.

Furthermore, the map element elevation determining means reads the map display element corresponding to the display target area from the map data storing means, and if necessary, based on the terrain shape model remodeled by the terrain shape elevation changing means. Determine the elevation value of each map display element and create display graphic data.
Then, the coordinate conversion means performs perspective projection conversion of the terrain shape model and the map display element for which the elevation value has been determined based on the viewpoint coordinates and the line-of-sight direction angle, and the drawing processing means further hides this perspective projection converted data. The three-dimensional map image is output by drawing while executing the surface deletion, and the three-dimensional map image is displayed on the image display means.

As a result, in this navigation system, the road map is displayed in a three-dimensional bird's-eye view view, the road map display is highly realistic for the user, and the guide route and the current position can be intuitively grasped by the user. . in addition,
Even if there are mountains higher than the display reference point on the viewpoint side by changing the elevation of the topographical data closer to the altitude of the display reference point for the elevation change area including the display reference point, In addition, the display reference point is always specified without obstructing the line of sight.

In the navigation system according to the third aspect of the present invention, the drawing processing means draws the guide route in a drawing color or line type different from that of the normal road to clearly distinguish the guide route from the normal road.

In the navigation system according to the fourth aspect of the present invention, when the drawing processing means draws the terrain shape, the drawing color is changed according to the altitude value of the terrain, and the terrain shape changes the altitude value to remodel. Even if it is changed, the drawing color is changed according to the elevation value before the change, so that the original undulation state is also changed by the display color change in the elevation change area including the display reference point deformed to a relatively gentle undulation. Will be displayed in a visually easy-to-understand manner.

In the navigation system of the fifth aspect of the present invention, the topographical data that can give elevation values to the topographical plane coordinates to the external storage means and the map display elements to be displayed on the map such as roads and place names. Map data that stores position information and incidental information is stored in advance.

By inputting the display reference point position coordinates and the line-of-sight direction angle for determining the position and direction of the displayed map from the input means such as the display reference point, the display target area determining means causes the display reference point position to be changed. The target area (display target area) on the map displayed on the screen is determined according to the coordinates and the line-of-sight angle, and the terrain shape modeling means sets a sampling point group of a predetermined density in the display target area. The elevation value z corresponding to the plane coordinates (x, y) of the sampling points is read from the terrain data storage means to generate a three-dimensional sampling point (x, y, z) group, and this three-dimensional sampling point group is predetermined. Create a polyhedral shape terrain shape model that is opened by connecting with ridgelines according to the rule.

The display reference point elevation determining means determines the elevation value of the display reference point from the input display reference point position coordinates and the terrain shape model, and the viewpoint coordinate determining means determines the display reference point position coordinates and the line-of-sight direction. The viewpoint coordinates of perspective projection conversion are determined from the angle and the display reference point elevation value.

Further, the altitude change area determining means determines the altitude change area for the display target area determined by the display target area determining means according to a preset rule in relation to the display reference point and the line-of-sight direction angle. For the sampling points belonging to this altitude change area, the terrain shape elevation changing means changes the elevation value of the corresponding point of the terrain shape model by the terrain shape modeling means to bring it closer to the elevation value of the display reference point. Remodel.

Further, the map element elevation determining means reads the map display element corresponding to the display target area from the map data storing means, determines the elevation value of each map display element based on the topographical shape model as necessary, and displays it. Create graphic data for use.

Then, the coordinate conversion means performs perspective projection conversion of the terrain shape model and the map display element for which the elevation value has been determined based on the viewpoint coordinates and the line-of-sight direction angle, and the terrain shape drawing processing means performs the perspective projection conversion. Draw a polyhedron showing the terrain shape that was created by overwriting from the back side to the viewpoint,
Output a 3D map image. At the same time, the map element elevation comparing means compares the elevation value of the display position of each map display element with the elevation value of the corresponding terrain shape, and based on the comparison result, the map element drawing processing means determines that the map display element is the map display element. Outputs a command for overwriting the terrain shape with respect to the terrain shape corresponding to or higher than the corresponding terrain shape. Then, the image display means displays the three-dimensional map image by overwriting and combining the three-dimensional map image from the topographic shape drawing processing means with the map element image from the map element drawing processing means.

As a result, in this navigation system, a road map is displayed in a three-dimensional bird's-eye view, a road map table that is highly realistic for the user is created, and the user can intuitively grasp the guide route, the current position, and the like. . Moreover, in the case of this navigation system, since the hidden surface elimination processing is not performed, the burden on the CPU for the arithmetic processing is reduced, and high-speed drawing is possible. In addition, regarding the elevation change area including the display reference point, the elevation of the topographical data is changed to be closer to the elevation of the display reference point, and the 3D map display is performed, so that there are mountains higher than the display reference point on the viewpoint side. Even if you do, you will always be able to clearly specify the display reference point without blocking your line of sight.

In the navigation system of the sixth aspect of the present invention, the map element elevation comparing means compares the elevation value of each display position of the map display elements with the elevation value of the corresponding terrain shape based on the terrain drawing color, and On the basis of the comparison result, the map element drawing processing means outputs a command for overwriting the terrain shape with respect to the terrain shape corresponding to or larger than the corresponding terrain shape of the map display element, so that the altitude value is higher. The map display element can be overwritten with the drawing color corresponding to the elevation value.

In the navigation system according to the seventh aspect of the present invention, the map element drawing processing means draws when the map display element is a guide route, a drawing color different from that of an ordinary road or a different line type. Clearly identifies the guide route.

In the navigation system according to the present invention, when the terrain shape drawing processing means draws the terrain shape, the drawing color is changed according to the altitude value of the terrain, and the terrain shape changes the altitude value. Even when remodeled, by changing the drawing color according to the altitude value before change,
With respect to the elevation change area including the display reference point which is deformed into a relatively gentle undulation, the original undulation state can be displayed in a visually easy-to-understand manner by changing the display color.

In the navigation system of the ninth aspect of the present invention, the terrain data storage means stores terrain shape data capable of giving elevation values to the terrain plane coordinates, and the line graphic data storage means stores roads, rivers, and railways. Store the positional information and incidental information to display such a line figure on the map,
Position information and incidental information for displaying a character string such as a place name in the place name and background data storage means, or position information and incidental information for displaying a surface figure represented by a polygon such as a background are stored.

By inputting the display reference point position coordinates for determining the position and direction of the displayed map and the line-of-sight direction angle from the input means such as the display reference point, the display target area determining means determines the display reference point position. The target area on the map (display target area) displayed on the screen is determined according to the coordinates and the line-of-sight angle, and the terrain shape modeling means sets a sampling point group of a predetermined density in the display target area, The elevation value z corresponding to the plane coordinates (x, y) of each sampling point is read from the terrain data storage means to generate a three-dimensional sampling point (x, y, z) group, and this three-dimensional sampling point group is A terrain shape model of a polyhedron shape opened by connecting with ridge lines according to a predetermined rule is created.

Further, the display reference point elevation determining means determines the elevation value of the display reference point from the input display reference point position coordinates and the terrain shape model by the terrain shape modeling means, and the viewpoint coordinate determining means inputs. The viewpoint coordinates for perspective projection conversion are determined from the display reference point position coordinates and the line-of-sight direction angle, and the display reference point elevation value by the display reference point elevation determining means.

Furthermore, the altitude change area determining means determines the altitude change area in accordance with a preset rule for the display target area by the display target area determining means in relation to the display reference point and the line-of-sight direction angle. The terrain shape elevation changing means changes the elevation value of the corresponding point of the terrain shape model by the terrain shape modeling means so that it approaches the elevation value of the display reference point for the sampling points belonging to this elevation changing area. Perform modeling.

Then, the map element elevation determining means reads the line figure data corresponding to the display target area from the line figure data storing means, the place name and the place name and background data from the background data storing means, and if necessary, the terrain shape. Based on the model, the display points of each line figure, place name, etc. and the elevation value of each surface figure are determined, and the display figure data is created. Perspective projection conversion is performed on the display graphic data of each map display element for which the elevation value has been determined, and the hidden surface removal drawing processing unit hides the topographic data, the place name, and the background data from the perspective projection converted data. It draws while erasing the surface and outputs a 3D map image. At the same time, the line figure data elevation comparing means compares the elevation value of the end point of each line element of the line figure data with the elevation value of the corresponding topographical shape, and based on the comparison result, the line figure data drawing processing means Outputs a command to draw by overwriting the terrain shape when the elevation value at the end point of the line element is equal to or higher than the corresponding terrain shape. Then, the image display means displays the three-dimensional road map by superimposing the line figure image from the line figure data drawing processing means on the three-dimensional map image from the hidden surface elimination drawing processing means.

As a result, in this navigation system, the road map is displayed in a three-dimensional bird's-eye view view, the road map is displayed highly realistic to the user, and the user can intuitively grasp the guide route, the current position, and the like. . in addition,
Even if there are mountains higher than the display reference point on the viewpoint side by changing the elevation of the topographical data closer to the altitude of the display reference point for the elevation change area including the display reference point, In addition, the display reference point is always specified without obstructing the line of sight.

In the navigation system according to the tenth aspect of the present invention, the map element altitude comparing means compares the altitude value of the display position of each map display element with the corresponding altitude value of the terrain shape based on the terrain drawing color to display the map. The image created for use can be used as it is, and the processing speed can be increased.

According to the eleventh aspect of the present invention, in the line graphic data drawing processing means, when the line graphic is a guide route, a drawing color different from that of an ordinary road,
Alternatively, the guide route can be clearly identified by drawing with different line types.

According to the twelfth aspect of the present invention, the viewpoint coordinate determining means changes the altitude coordinate value of the viewpoint coordinates in accordance with the display reference point altitude value determined by the display reference point determining means, whereby the display reference point is changed. Even if the altitude value of changes, the bird's-eye view is displayed with the altitude of the display reference point as the reference plane, and when the current vehicle position is used as the display reference point, the viewpoint dives below the ground surface and correct display cannot be performed. You can avoid troubles.

In the navigation system of the thirteenth aspect of the present invention, the altitude change area determining means has a certain front side including the display reference point from the viewpoint with respect to the display reference point elevation value determined by the display reference point elevation determining means. By determining the side area as the elevation change area, even if the original elevation is high enough to hide the display reference point for the point included in the front side area including the display reference point from the viewpoint, the display reference point is displayed. Even if there is a mountain or the like higher than the display reference point on the viewpoint side, the display reference point is always displayed without being obstructed by the line of sight.

In the navigation system of the fourteenth aspect of the present invention, the altitude changing area determining means sets a constant circular area including the display reference point to the altitude changing area with respect to the display reference point altitude value determined by the display reference point altitude determining means. By deciding that, even if the original elevation of the points included in the surrounding area including the display reference point is high enough to hide the display reference point, the display is changed to an elevation close to the display reference point. Even if there is a high mountain near the display reference point, the display reference point is always displayed without obstructing the line of sight.

In the navigation system of the fifteenth aspect of the present invention, the terrain shape elevation changing means belongs to each of the elevation changing areas with respect to the elevation value (hp) of the display reference point determined by the display reference point elevation determining means. By changing the elevation value (denoted as h) of the sampling point by h ← (h-hp) × α + hp, where 1> α ≧ 0, and setting a new elevation value h, from the viewpoint, Even if the original elevation of a point included in the area on the near side including the display reference point or the area around the display reference point is such that the original reference elevation is high enough to hide the display reference point, the elevation is changed to a height close to the display reference point. Will be displayed.

In the navigation system of the sixteenth aspect of the present invention, when the hidden surface removal drawing processing means draws the terrain shape, the drawing color is changed according to the elevation value of the terrain, and the terrain shape changes the elevation value. Even when remodeled by changing the drawing color according to the elevation value before change, the display color of the elevation change area including the display reference point that is relatively gently undulated or deformed in a plane Due to the change, the original undulation state will be displayed in a visually easy-to-understand manner.

In the navigation system of the seventeenth aspect of the present invention, the terrain data storage means stores the terrain shape data capable of giving elevation values to the terrain plane coordinates, and the map data storage means stores the map of roads, place names, etc. The position information and the incidental information of the map display element displayed in are stored.
When it becomes necessary to display the guide route, the display reference point position coordinates and the line-of-sight direction angle for determining the position and direction of the map displayed by the display reference point input means are input.

In this way, the display target area determining means determines the target area on the map (display target area) displayed on the screen according to the input display reference point position coordinates and the line-of-sight direction angle, and the plane / stereoscopic display is performed. The area determination means determines a flat display area and a stereoscopic display area for the display target area according to a preset rule in relation to the display reference point and the viewing direction angle.

Then, the terrain shape modeling means reads the terrain shape data of the sampling points belonging to the display target area from the terrain data storage means, models the terrain shape using the terrain shape data, and displays reference point elevation determining means. Determines the elevation value of the display reference point from the display reference point position coordinates and the terrain shape model by the terrain shape modeling means, and the viewpoint coordinate determination means determines the display reference point position coordinates and the line-of-sight direction angle and the display reference point elevation value. From, the viewpoint coordinates of perspective projection transformation are determined.

Further, the map element elevation determining means reads the map display element corresponding to the stereoscopic display area from the map data storage means, and if necessary, the elevation value of each map display element based on the topographic shape model by the topographic shape modeling means. Determine the 3D display graphic data, and the constant altitude value setting means reads the map display element corresponding to the flat display area from the map data storage means, and sets the altitude value almost equal to the display reference point altitude value. Set the elevation value of the map display element and create the graphic data for plane display.

Then, the coordinate conversion means uses the viewpoint coordinates determined by the viewpoint coordinate determination means and the line-of-sight direction angle input from the display reference point input means to input the topographical shape model and the stereoscopic display graphic data of the map display element. And perspective projection conversion, and the stereo map drawing processing means draws a stereo map image of the display target area based on the topographic data, the place name, and the background data in the perspective projection converted data, and further draws a plane bird's eye view. With respect to the plane display graphic data created by the constant elevation value setting means, the processing means performs an overwriting drawing process on the stereoscopic map image in order to display the plane bird's-eye view at the constant altitude value, and the image display means performs the stereoscopic map drawing processing means. The three-dimensional map image by the above and the two-dimensional bird's-eye view map image by the plane bird's-eye view drawing processing means are combined and displayed.

As a result, in this navigation system, a three-dimensional bird's-eye view of the road map is displayed in the three-dimensional display area of the display target area, the road map is displayed with a high sense of reality for the user, and the guide route and the current position are used. Make the person intuitively understand. In addition, for the plane display area including the display reference point, the elevation of the terrain data is made to match the elevation of the display reference point and is overwritten and displayed on the stereoscopic map image in the form of a plane bird's-eye view so that it is closer to the viewpoint than the display reference point. Even if there are high mountains, the surroundings of the display reference point are always clearly displayed without obstructing the line of sight.

According to the eighteenth aspect of the present invention, in the navigation system according to the thirteenth aspect, image clipping is performed on a boundary portion between the stereoscopic map image by the stereoscopic map drawing processing means by the image clipping means and the plane bird's-eye view map image by the plane bird's-eye view drawing processing means. By doing so, the connection portion between the three-dimensional map image and the two-dimensional bird's-eye view image is smoothed to display an easily viewable three-dimensional road map.

In the navigation system according to the nineteenth aspect of the present invention, both the three-dimensional map drawing processing means and the plan bird's-eye view drawing processing means draw the guide route in a drawing color or line type different from that of the normal road, so that the guide route is drawn. Clearly identify.

In the navigation system of the twentieth aspect of the invention, the plane / stereoscopic display area determining means has a certain front side including the display reference point with respect to the display target area determined by the display target area determining means. Area is the plane display area,
By determining the area on the back side as a stereoscopic display area, the original elevation of the point included in the area on the front side including the display reference point from the viewpoint is high enough to hide the display reference point. Even if there is, the display is changed to an altitude close to the display reference point, and even if there is a mountain or the like higher than the display reference point on the viewpoint side, the display reference point is always displayed without obstructing the line of sight.

In the navigation system according to the twenty-first aspect of the present invention, the plane / stereoscopic display area determining means defines a fixed circular area surrounding the display reference point with respect to the display target area determined by the display target area determining means. By determining the other area as the stereoscopic display area, even if the original elevation is high enough to hide the display reference point, it becomes the display reference point for the points included in the surrounding area including the display reference point. Even if there is a high mountain near the display reference point, the display reference point will not be obstructed and the display reference point will always be clearly displayed.

In the navigation system according to the twenty-second aspect of the invention, when the plane bird's-eye view drawing processing means draws the plane display area, by changing the drawing color of the area corresponding to the elevation value of the original topographical shape, With respect to the elevation change region including the display reference point which is deformed in a plane, the original undulation state can be displayed in a visually easy-to-understand manner by changing the display color.

[0077]

[0078]

[0079]

[0080]

[0081]

According to the first and second aspects of the present invention, the road map is displayed in a three-dimensional bird's-eye view, the road map is displayed in a highly realistic manner for the user, and the guide route and the current position are intuitive to the user. In addition, regarding the elevation change area including the display reference point, the elevation of the topographical data is changed to approach the elevation of the display reference point, and the 3D map display is performed, so that Even if there is a high mountain or the like on the side, the display reference point can always be clearly indicated without obstructing the line of sight.

According to the third aspect of the present invention, the guide route can be clearly distinguished from the normal road by drawing the guide route in a drawing color or line type different from that of the normal road.

According to the fourth aspect of the present invention, the original undulation state can be displayed in a visually easy-to-understand manner by changing the display color even in the elevation change area including the display reference point which is deformed into a relatively gentle undulation. it can.

According to the invention of claim 5, the road map is displayed in a three-dimensional bird's-eye view, the road map table is highly realistic for the user, and the guide route and the current position are intuitively grasped by the user. Can be done, and because the hidden surface removal processing is not performed,
High-speed drawing is possible by reducing the load on the CPU related to arithmetic processing. In addition, for the elevation change area including the display reference point, the elevation of the topographical data is changed to be close to the elevation of the display reference point, and a three-dimensional map display By performing the above, even if there is a mountain or the like higher than the display reference point on the viewpoint side, the display reference point can always be clearly displayed without obstructing the line of sight.

According to the invention of claim 6, the elevation value of the display position of each map display element is compared with the elevation value of the corresponding terrain shape based on the terrain drawing color, and based on the comparison result, the map display element is compared. Will output the command to draw the terrain shape by overwriting the terrain shape for which the corresponding terrain shape is equal to or greater than the terrain shape, so the map display element with a high elevation value is drawn with the drawing color corresponding to the elevation value. It can be overwritten and displayed in an easy-to-understand manner.

According to the seventh aspect of the present invention, when the map display element is a guide route, the guide route is clarified by drawing with a drawing color different from that of a normal road or with a different line type. Can be identified.

According to the eighth aspect of the present invention, the original undulation state can be recognized by the change of the display color in the elevation change region including the display reference point which is deformed to a relatively gentle undulation. According to the invention of claim 9, the road map is displayed in a three-dimensional bird's-eye view view, the road map is highly realistic for the user, and the user can intuitively grasp the guide route, the current position, and the like. In addition, regarding the elevation change area including the display reference point, the elevation of the topographical data is changed to be closer to the elevation of the display reference point, and the 3D map display is performed, so that there are mountains higher than the display reference point on the viewpoint side. Even when doing so, the display reference point can always be specified without obstructing the line of sight.

According to the tenth aspect of the present invention, the elevation value of the display position of each map display element and the elevation value of the corresponding terrain shape are compared based on the terrain drawing color, so the image created for display is used as it is. Therefore, the processing speed can be increased.

According to the eleventh aspect of the present invention, when the line figure is a guide route, the guide route is clearly identified by drawing with a different drawing color or a different line type from that of a normal road. Can be made.

According to the twelfth aspect of the present invention, by changing the elevation coordinate value of the viewpoint coordinate according to the display reference point elevation value, even if the elevation value of the display reference point changes, the elevation of the display reference point becomes the reference. When a three-dimensional bird's-eye view display is made flat and the current position of the vehicle is used as the display reference point, it is possible to avoid the problem that the viewpoint dives below the ground surface and correct display cannot be performed.

According to the thirteenth aspect of the present invention, with respect to the display reference point elevation value, a certain front side area including the display reference point from the viewpoint is determined as the elevation change area, and the display is seen from the viewpoint. Even if the original elevation of a point included in the front side area including the reference point is high enough to hide the display reference point, the display is changed to an altitude close to the display reference point, and the point of view rather than the display reference point is displayed. Even if there is a high mountain or the like on the side, the display reference point can always be clearly indicated without obstructing the line of sight.

According to the fourteenth aspect of the invention, for the display reference point elevation value, a constant circular area including the display reference point is determined as the elevation change area, so that it is included in the surrounding area including the display reference point. About the point to be displayed, even if the original altitude is high enough to hide the display reference point, it is changed to an altitude close to the display reference point and displayed, and even if there are high mountains near the display reference point The display reference point can always be specified without obstructing the line of sight.

According to the fifteenth aspect of the present invention, the elevation value of each sampling point belonging to the elevation change area is changed to a new elevation value with respect to the elevation value of the display reference point. Therefore, even if the original elevation of a point included in the area on the near side including the display reference point from the viewpoint or the area around the display reference point is close to the display reference point even if the original elevation is high enough to hide the display reference point. The altitude can be changed and displayed.

According to the sixteenth aspect of the present invention, when the terrain shape is drawn, the drawing color is changed according to the elevation value of the terrain, and the terrain shape is remodeled by changing the elevation value. Also changes the drawing color according to the elevation value before the change, so the original undulation state can be visually visualized by changing the display color even in the elevation change area that includes the display reference point that is relatively gentle undulation or is planarly deformed. Can be displayed in an easy-to-understand manner.

According to the seventeenth aspect of the present invention, the road map is displayed as a three-dimensional bird's-eye view for the three-dimensional display area in the display target area, and the road map is displayed with a high sense of reality for the user. In addition, the user can intuitively understand, and, in addition, for the plane display area including the display reference point, the elevation of the topographical data matches the elevation of the display reference point and overwrites it on the 3D map image in the form of a plane bird's-eye view. By displaying, even when there is a mountain or the like higher than the display reference point on the viewpoint side, the periphery of the display reference point can be always clearly displayed without obstructing the line of sight.

According to the eighteenth aspect of the present invention, by performing image clipping of the boundary portion between the three-dimensional map image and the two-dimensional bird's-eye view map image, the connection portion between the three-dimensional map image and the two-dimensional bird's-eye view image is smoothed and is easy to see. A road map can be displayed.

According to the nineteenth aspect of the present invention, the guide route is clearly identified by drawing the guide route in the three-dimensional map image and the planar bird's-eye view map image with a drawing color or line type different from that of a normal road. You can

According to the twentieth aspect of the invention, with respect to the display target area, a fixed front side area including the display reference point from the viewpoint is a flat display area, and an area on the back side is a stereoscopic display area. By making a decision, the point included in the area on the front side including the display reference point from the viewpoint is changed to an altitude close to the display reference point even if the original altitude is high enough to hide the display reference point. Even if there are mountains or the like higher than the display reference point on the viewpoint side, the display reference point can always be clearly displayed without obstructing the line of sight.

According to the twenty-first aspect of the invention, with respect to the display target area, the constant circular area surrounding the display reference point is determined as the flat display area, and the other areas are determined as the stereoscopic display area. Including the points included in the surrounding area, even if the original altitude is high enough to hide the display reference point, the display is changed to an altitude close to the display reference point, and a high mountain is displayed near the display reference point. Even if it exists, the display reference point can be always specified without obstructing the line of sight.

According to the twenty-second aspect of the present invention, when the plane display area is drawn, the drawing color of the corresponding area is changed according to the elevation value of the original topographical shape, so that the display reference deformed in a plane is used. With respect to the elevation change area including points, the original undulation state can be displayed in a visually easy-to-understand manner by changing the display color.

[0101]

[0102]

[0103]

[0104]

[0105]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows a system configuration according to one embodiment of the present invention. In terms of hardware, it is detected by a conventionally known GPS sensor or by self-contained navigation based on signals from a vehicle speed sensor, a direction sensor and a gyro sensor. Display reference point position input device 1 for calculating display reference point position coordinates and line-of-sight direction angle by designating a current position and traveling direction of a vehicle to be operated, or by designating an arbitrary point and traveling direction by a remote controller or a keyboard.
And an external storage device 2 for storing topographical data 2a composed of elevation value data of each point and map data 2b including road and place name information, a CPU capable of high-speed arithmetic processing, an internal storage device, and an input / output interface. It comprises an arithmetic processing unit 3 which is provided with a computer, and an image display unit 4 which displays an image signal output from the arithmetic processing unit 3.

As the topographical data 2a, the altitude value data for each actual longitude / latitude coordinate point as shown in FIG. 3A is stored in the form of a matrix table as shown in FIG. 3B. That is, a constant density in the horizontal direction,
For example, for each point (sampling point) arranged in a grid pattern at regular intervals in each of the meridian (y) and latitude (x) directions, the actual elevation value at that point is stored in a matrix table format.

Further, in the external storage device 2, the elevation value data in which such topographical data 2a is described for sampling points of plural kinds of density are regarded as different topographical data or different accuracy. Can be remembered. For example, every 100m, 500
The altitude data of the sampling points arranged every m and every 5 km are separately stored as the terrain data 2a of three kinds of accuracy. In this case, only one type of altitude data of 100 m sampling points, which is physically the highest accuracy, is stored as topographical data and used as it is according to the scale designation at the time of map display, or every 5 points exist. It is also possible to extract what is done as medium-precision terrain data, and to extract what is present at every 50 points as low-precision terrain data for use.

The data format of the topographical data 2a itself is not limited to this, and may be data represented by actual contour lines as shown in FIG. 4, and for example, z as latitude x and longitude y. It is also possible to register in the form of the curved surface equation given by = f (x, y), and the data form is not particularly limited. Map data 2b
Stores the display elements such as roads and place names displayed on the map and their position information and, if necessary, supplementary information such as attributes. For example, regarding a road, the position coordinates of a series of points indicating each end point are displayed as ridges or a series of ridges as position information of the road, and lakes, rivers, golf courses, and stations with wide basins are used. For area figures such as premises, the position coordinates of a series of points indicating each vertex and internal division points are displayed as polygons and used as the positional information of the relevant water system and facility, and the connection form of each point is an attribute. Is equipped with.

That is, when the water system or facility as shown in FIG. 5A is defined by the vertices 1 to 5 and the internal points 6 and 7, a small polygon to be divided (here, a triangle, (Not limited to the above), that is, a set of vertices constituting the same, that is, a set of vertices shown in FIG. Therefore, when describing this water system or facility, 7
By drawing two adjacent small polygons (here, small triangles) according to the connection form that is an attribute, the entire surface figure such as a water system or facility is displayed.

In addition, regarding the place name and the road name, the coordinates of the position where the character string is displayed on the map are used as the position information, and the character string is provided as the attribute. Further, the attribute information added to the road link includes the type of the road (because it is necessary to change the display color depending on whether it is a highway, national road, or prefectural road) and form (whether it is a normal road, a tunnel, or an overpass). There is. These pieces of position information can be described and stored as two-dimensional coordinates corresponding to longitude and latitude, and can also be stored as three-dimensional coordinates including altitude value data.

Further, regarding the guide route to the destination obtained by the execution of another program by the CPU or the guide route set by the user himself, it is the guide route at each link (line element) of the corresponding road data. It is stored in the internal memory so that it can be distinguished from a normal road by setting a flag indicating that For example,
When the road data is represented by connecting short straight lines (line elements), the road data is (x0, y0), (x1,
When it is specified that each coordinate of y1), (x2, y2), (x3, y3), ... Is connected by a straight line, it is specified as a guide route for such road data. , (X0, y0; 1), (x1, y1; 1), (x
2, y2; 1), ... Flags are set to identify these as line elements (links) of the guide route.

The structure of various arithmetic processing functions executed by the arithmetic processing unit 3 will be described. A display target area determining section 3-1, a terrain shape modeling section 3-2, and a display reference point elevation determining section 3-.
3, viewpoint coordinate determination unit 3-4, altitude change determination unit 3-5, terrain shape altitude change unit 3-6, map element altitude determination unit 3-7,
The coordinate conversion unit 3-8 and the drawing processing unit 3-9 are included.

The display target area determining unit 3-1 is a target on the map displayed as shown in FIG. 6 based on the display reference point coordinates and the line-of-sight direction angle input from the input device 1 such as the display reference point. This is a part that determines the area on a horizontal plane virtually placed at the same altitude as the display reference point. The terrain shape modeling unit 3-2 sets a point group appropriately distributed as shown in FIG. 7 in the display target area determined by the display target area determination unit 3-1 and sets the plane coordinates (x, The elevation value z corresponding to y) is read from the topographical data 2b to generate three-dimensional data of (x, y, z), and this (x, y, z) is used as an apex, and an appropriate ridge line is provided between each apex. It is a part that connects with to create a polyhedron showing the topographical shape.

The display reference point elevation determining unit 3-3, as shown in FIG. 8, displays the x and y coordinate values (Px, Py) of the display reference point input from the display reference point input device 1 and the terrain shape. This is a part for interpolating the height direction z coordinate value Pz of the display reference point from the topographical shape obtained by the modeling part 3-2, and the viewpoint coordinate determination part 3-4 is the display reference point elevation determination part 3.
Position coordinates of the display reference point (Px, Py, P
This is a part for obtaining the coordinates (Vx, Vy, Vz) of the viewpoint based on z).

As shown in FIG. 10, the altitude change area determination unit 3-5 sets a constant area around the display target area determined by the display target area determination unit 3-1 with reference to the display reference point. For example, as shown in FIG. 7A, a region orthogonal to the viewing direction on the near side from the viewpoint is determined as the altitude change region, or a constant region surrounding the display reference point as shown in FIG. Is a portion for determining the altitude change area. In the following description, it is assumed that a region orthogonal to the sight line direction on the front side as viewed from the viewpoint as shown in FIG.

The terrain shape elevation changing unit 3-6 determines the elevation determined by the elevation changing area determining unit 3-5 as shown in FIG. 9 with respect to the terrain shape model modeled by the terrain shape modeling unit 3-2. This is a part in which the elevation value of each sampling point belonging to the changed area is forcibly brought closer to the elevation value of the display reference point obtained by the display reference point elevation determination unit 3-3 and remodeling is performed.

The map element altitude determining unit 3-7 reads the map element data in the display target area from the map data 2b, and if there is no altitude value, the map reference point altitude determining unit 3-3 uses the same procedure as the calculation process. This is a part for performing a process for obtaining a corresponding altitude value by insertion.

The coordinate conversion section 3-8 is a section for obtaining two-dimensional coordinates (Sx, Sy) and depth coordinates Sz on the display screen by perspective projection conversion, and the drawing processing section 3-9 has a depth coordinate for each pixel. Are compared with each other, and only the pixels having a depth smaller than the already drawn pixels are updated and drawn to generate a stereoscopic map drawing signal with hidden surface removal enabled, and the stereoscopic map drawing signal is output to the image display device 4. This is a part for displaying a three-dimensional road map. Different drawing colors are assigned depending on the altitude value, and different drawing colors are assigned to roads, rivers, place names, etc. Furthermore, for the guide route, a drawing color different from that of a normal road, especially a prominent color, for example,
Assign colors such as red, yellow, and blue.

Next, the operation of the navigation system having the above configuration will be described with reference to the flowchart of FIG. The display processing of the three-dimensional map on the display screen of the image display device 4 by the arithmetic processing device 3 includes determination of the display target area, topography and map data every time the display reference point input from the input device 1 such as the display reference point is updated. Reading, determination of viewpoint coordinates,
Creation of display graphic data, coordinate conversion by perspective projection method,
It is executed by repeating a series of arithmetic processing such as drawing processing such as clipping.

When the position coordinates and the line-of-sight direction angle of the display reference points are input from the display reference point input device 1, the display target area determining unit 3-1 of the arithmetic processing device 3 causes the display target point determining unit 3-1 to display the position coordinates of these display reference points. And the target area on the map displayed on the screen is determined based on the line-of-sight direction angle. Then, the altitude change area determination unit 3-5 sets an altitude change area for this display target area (step S1).

Here, the display reference point is a representative point in the display screen for determining the position of the displayed map, and the line-of-sight direction angle is the azimuth angle of the orthogonal projection of the line-of-sight on the horizontal plane. That is. And to input this display reference point, for example, in a car navigation system,
When displaying the map of the current position of the host vehicle in the vicinity of the center input device, the host vehicle position measuring device that measures and outputs the current position and the traveling direction by the GPS sensor, the vehicle speed sensor, and the gyro sensor is displayed as a reference point. It can be used as the input device 1. Alternatively, when the user designates an arbitrary point on the map and displays the map in the vicinity in the desired line-of-sight direction, a point designating means such as a remote controller or a keyboard as the display reference point output device 1. Can also be used.

Here, the positional relationship between the viewpoint, the display reference point, and the display target area will be described with reference to FIG. The display target area is specified by the two-dimensional coordinate system (x, y) corresponding to longitude and latitude regardless of the altitude value, and here, the horizontal plane having the same altitude as the display reference point is assumed to be the map plane. Further, if the height of the viewpoint coordinates is described by the offset h from the altitude value of the display reference point, the positional relationship shown in FIG. 6 is always established regardless of the altitude, and the conventional bird's-eye view display navigation system is used. Similarly, the display target area can be specified. That is, when the two-dimensional position coordinates (Px, Py) excluding the altitude of the display reference point and the line-of-sight direction angle φ are given from the display reference point input device 1, a predetermined viewpoint height offset h, a line-of-sight depression angle θ, The display target area can be obtained using the viewing angle β, the display reference point display position δ, and the like.

The altitude change area determination unit 3-5 sets display reference points for the display target area determined by the display target area determination unit 3-1 according to a preset rule as shown in FIG. Set the elevation change area in front of the included viewpoint.

Next, as shown in FIG. 7, the terrain shape modeling section 3-2 reads the terrain data in the range that can sufficiently cover the display target area obtained in step S1 from the external storage device 2 to model the terrain shape. (Step S
2). When reading this topographical data, some or all of the necessary data has been used for the previous display processing, and the internal storage device (not shown) of the arithmetic processing unit 3 has already been used.
When the data is stored in the memory, the internal storage data is used as the data of the overlapping portion, and only the necessary data is read from the external storage device 2 to shorten the data transfer time.

In the terrain shape modeling process, the process shown in FIG.
As shown in, the sampling points included in a range that sufficiently covers the display target area determined by the display target area determination unit 3-1 (that is, (x, y) points at which topographical data is registered). Group) is set, the elevation value data z is read for each sampling point, a vertex is generated at the (x, y, z) coordinates for each sampling point as shown in FIG. As shown in (c), these vertices are connected to each other with adjacent latitudes and longitudes to generate a small quadrilateral (not necessarily a plane), and further, in each of these small quadrilaterals, for example, southeast -An open polyhedron shape is created by dividing it into two small triangles (which become a plane) by a diagonal line connecting the northwest vertices.

Next, the display reference point elevation determining section 3-3 determines the elevation value Pz of the display reference point (Px, Py) (step S3). This includes an input device 1 such as a display reference point.
Can input the elevation value Pz with sufficient accuracy, the value can be directly used. However,
In the case of a system where sufficient accuracy is not guaranteed, or the elevation value Pz
In the case of a system that does not measure itself, the display reference point is 2
A corresponding altitude value Pz is approximately calculated from the dimensional position coordinates (Px, Py) and the terrain data read in the previous step S2. This method will be described with reference to FIG. First, among the sampling points that give the elevation value of the topographic data, xy2
Three points that are close to the display reference point (Px, Py) in the dimensional coordinate system are obtained. Next, as the points A, B, and C in the three-dimensional space in which the elevation values are given to these three points, the equation of the plane passing through these three points A, B, and C is obtained. The z value obtained by substituting (x, y) = (Px, Py) into the equation of this plane is taken as the elevation value Pz of the display reference point. That is, if the position vectors of the three spatial points A, B, and C are A, B, and C, Pz can be calculated by the following equation (1).

[0127]

[Equation 1] However, here

[Equation 2] And (Dx, Dy, Dz) represents a vector perpendicular to the plane defined by the three points A, B, and C.

Next, the viewpoint coordinate determining unit 3-4 adds the predetermined viewpoint height offset h to the altitude value Pz of the display reference point thus obtained, thereby increasing the height of the viewpoint coordinates. Directional coordinate value Vz (= Pz + h)
Ask for. The xy coordinates (Vx, Vy) of the viewpoint are also obtained based on the line-of-sight direction angle and the like (step S4). That is, the viewpoint coordinates (Vx, Vy, Vz) are calculated based on the following equation (3) with reference to FIG.

[0129]

[Equation 3] Next, the terrain shape elevation changing unit 3-6 uses the open polyhedral terrain shape model as shown in FIGS. 7C and 9B modeled by the terrain shape modeling unit 3-2.
The altitude value data hi of each sampling point belonging to the altitude change region determined by the altitude change region determination unit 3-5 is shown in FIG.
As shown in (c), based on the display reference point elevation value Pz determined by the display reference point elevation determination unit 3-3, the following equation (4)
Change based on.

Hi ← (hi−Pz) × α + Pz (4) Here,
1> α ≧ 0, which is set in advance.

For the sampling point i (x, y) belonging to the altitude change area, the altitude value data calculated by the equation (4) is used, that is, (x, y, hi) is used, and the remaining area of the display target area is used. With respect to the part (1), the original topographical data (x, y, z) is used to re-model the topographical shape model to obtain an open polyhedral shape as shown in FIG. 9D (step S5). In this example, α = 0 is set, and the altitude changing process is performed to make the altitudes hi of all sampling points in the altitude changing region equal to the altitude Pz of the display reference point.

Next, the map element elevation determining unit 3-7 reads the map element data such as roads and place names in the display target area from the map data 2b of the external storage device 2 based on the display target area, and also changes the altitude. If there is no value data, the process of determining the corresponding elevation value by interpolation is performed as in the procedure of calculating the display reference point elevation value (step S6).

That is, the map data 2b has the position coordinates of each map display element as position information. If this is described by the two-dimensional coordinates (x, y), it means that it is a display reference point. Similarly, for each map display element, three sampling points including the position coordinates thereof are specified, and the elevation value data for each of these three sampling points is obtained from the topographical shape data obtained in step S5. ) The elevation value of each map display element is calculated based on the equation.

When the altitude value determination processing for all map display elements is completed in this way, the coordinate conversion unit 3-8 executes the processing of step S7 in the flowchart of FIG.
That is, the perspective projection conversion is executed. In this perspective projection transformation, the perspective projection transformation is performed on the display graphic data such as the terrain shape, the map display element, and the display reference point, and the coordinate value on the display screen is calculated. When this conversion formula is expressed in the homogeneous coordinate system, the following formula (5) is obtained.

[0135]

[Equation 4] Here, the vector M is the map space coordinates (Mx, My, Mz) of the display graphic data to be converted, and 1 is added as the fourth component, and Vx, Vy, Vz are the viewpoint coordinates obtained by the equation (3). , Φ, θ are gaze direction angles and depression angles, f, n are upper and lower limit values that specify the clipping range in the depth coordinates, and Ds is a theoretical distance from the viewpoint to the display screen in pixel units.

Homogeneous coordinates obtained as a result of the conversion T =
For (Tx, Ty, Tz, Tw), the two-dimensional coordinates (Sx, Sy) used for drawing are Sx = Tx / Tw, S
It is calculated by y = Ty / Tw. The depth coordinate is S
z = Tz / Tw.

After this perspective projection conversion processing, the drawing processing unit 3
-9 executes a drawing process including hidden surface removal and outputs it to the image display device 4 to display a stereoscopic bird's-eye view of the road map (step S8).

In this processing, each drawing element after coordinate conversion is subjected to clipping processing or the like for drawing. Regarding the clipping in the x and y directions, based on the drawing range determined in advance by the size of the display screen, only those in which (Sx, Sy) are within this range are drawn, and other parts are not drawn. In the depth direction, n ≦ S
Only objects within the range of z ≦ f are to be drawn. Further, for pixels to be rendered, depth coordinates are compared for each pixel, and only those with a depth smaller than the already rendered pixels are updated and rendered, thereby rendering a three-dimensional map with hidden surface removal enabled. .

Each drawing element to be drawn is displayed using a predetermined drawing color. In this case, for example, the terrain shape is drawn by using a drawing color that continuously changes according to the altitude value as shown in FIG. In this case, the correspondence between the altitude value and the drawing color to be assigned to the altitude value is determined in advance, and for example, the altitude value 0 to 50 m, 50 to 100 m, 100 to 200 m,
It is possible to draw as shown in FIG. 11 by giving the altitude value a width of 200 to 400 m and assigning the same color to the altitude values falling within the range.

It is also possible to draw the ridgeline at the same time as drawing the surface of the polyhedron representing the terrain shape. Then, in this case, as shown in FIG.
By drawing only those that correspond to the meridian direction (do not draw the dashed ridgelines), simply display the ridgelines clearly and 3
Not only can the effect of recognizing the topography as a dimensional shape be enhanced, but also the directions of north, south, east, and west can be clearly recognized on the three-dimensional map.

Each drawing element is executed by filling the corresponding pixel on the display screen with a predetermined drawing color for each pixel. When filling the pixel located at the screen coordinates (Sx, Sy), Corresponding depth coordinate Sz
Is stored in the register corresponding to (Sx, Sy),
Next, when trying to paint the same pixel (Sx, Sy) for another drawing element, the new depth coordinate Sz1 is compared with the value Sz0 already stored in the corresponding register, and Sz1
Is smaller, that is, only when the element to be drawn later is closer to the viewpoint, the drawing color of the corresponding pixel and the depth coordinate in the register are updated. If not, it is not updated. . This process is a method of hidden surface removal called Z buffering, and a pixel close to the viewpoint is always displayed for each pixel regardless of the order in which the drawing elements are drawn.

By enabling such Z buffering, as shown in FIG. 13, the drawing elements existing on the other side are displayed in such a manner that only the overlapping portions on the same line of sight are hidden, and the drawing elements are changed according to the movement of the viewpoint. The visible range is gradually changed, and a more realistic expression can be made.

In this way, by executing the drawing processing up to step S8, one stereoscopic map screen is created and the image display device 4
It is determined whether or not to continue the map display in step S9, and if it continues, the procedure returns to step S1 and the procedure for creating and displaying the next screen is repeated. If the process is not continued, the above-described series of processing procedures are ended, and the process is moved to another process of the navigation system such as vehicle position detection and route calculation.

As described above, the map screen based on the stereoscopic bird's-eye view according to the first embodiment of the present invention displays the map on the topographical shape three-dimensionally expressed based on the elevation value data of the actual topographical shape and the map data. A 3D map with display elements can be created and displayed, a map display that gives the user a sense of reality can be displayed, and the current position can be confirmed and the relationship with the surrounding environment can be intuitively recognized. In addition, since the altitude of the sampling points belonging to the elevation change area near the display reference point is adjusted to be closer to the display reference point, change correction is performed.
As shown in FIG. 14, even if there is a mountain or the like which is originally higher than the display reference point on the viewpoint side and the display reference point cannot be seen because it is hidden by the mountain from the viewpoint, the present invention According to this, it becomes possible to always display the periphery of the display reference point, and particularly when the position of the own vehicle is used as the display reference point, it becomes possible to always grasp the existing point of the own vehicle, which is not practical. improves.

In the first embodiment, the drawing processing unit 3-9 draws the terrain shape in different drawing colors according to the altitude value, but the area in which the terrain shape is changed corresponds to the corresponding range. It is also possible to use a drawing color according to the original topographical elevation value of. As a result, even if the background is deformed into gentle undulations, it becomes possible to visually grasp the undulations of the terrain by the drawing color.

Next, FIG. 15 shows a second embodiment of the present invention.
~ It demonstrates based on FIG. The feature of the second embodiment is that the drawing processing as in the first embodiment is performed on the data of the perspective projection conversion processing result executed by the coordinate conversion unit 3-8 in the arithmetic processing device 3. By omitting the hidden surface removal processing performed by the unit 3-9, instead performing the processing of sequentially drawing from the back surface to the front side in the display target area from the back surface to the front side in the first embodiment. The point is that the 3D map can be drawn as in the case of the form.

The structure of the second embodiment will be described with reference to FIG. The hardware configuration is the same as that of the first embodiment shown in FIG.
The configuration of the arithmetic processing function in is changed.
The arithmetic processing unit 3 includes a display target area determination unit 3-1 to a terrain shape elevation change unit 3-6 similar to those in the first embodiment. The map element elevation determining unit 3-7 ', the coordinate converting unit 3-8', the terrain shape drawing processing unit 3-10, and the map element elevation comparing unit 3-1 are constituent elements different from those of the first embodiment.
1 and a map element drawing processing unit 3-12.

Of the new components, the map element elevation determining unit 3-7 'reads the map element data in the display target area from the map data 2b, and if the elevation value is not registered, the display reference point elevation determining unit. Similar to 3-3, this is a part for calculating a corresponding elevation value by interpolation based on the equations (1) and (2) using three sampling points surrounding the representative point.

The coordinate transformation unit 3-8 'is a portion for obtaining the two-dimensional coordinates (Sx, Sy) on the display screen by perspective projection transformation, but unlike the first embodiment, the depth coordinate Sz.
Does not ask.

The terrain shape drawing processing unit 3-10 is a part for drawing the polyhedron indicating the terrain shape by sequentially overwriting from the surface toward the back. Even in the drawing process of the terrain shape, the drawing color is changed according to the altitude value. The map element elevation comparison unit 3-11, for each map display element, in the case of a road, a water system, a facility, etc., an endpoint of each constituent point, and in the case of a place name, only the representative point thereof and the elevation value on the screen. This is the part to compare with the terrain elevation value already drawn at the same position. Here, if the elevation value of the map display element is not smaller, it is assumed to be in front of the ground surface. 16 (a), 16 (b)
As shown in, when it is attempted to draw a map display element at the position of the point P on the bird's-eye view, if the terrain shape is already drawn in the drawing color according to the elevation value, the color of the pixel at the point P is On the line, the altitude value h1 of the point A closest to the viewpoint is shown. Therefore, if the elevation value of the map element to be drawn is smaller than this, this map element will be present at the point B on the back side of the mountain in the figure, and will be hidden and invisible.

In the case of a road, the map element drawing processor 3-12 draws the line elements as usual if both end points of both line elements are smaller than the ground surface. This is a part for performing a process of drawing if the value is small and not drawing if the value is small and outputting the instruction to the image display device 4. That is, as shown in FIG. 17, since the terrain shape is modeled by approximating a polyhedron, even if the elevation value of the road is obtained for each constituent point, if the terrain shape between the constituent points is convex, the road can be seen. Disappear. In the hidden surface removal processing executed in the first embodiment, in order to determine whether each pixel is visible or hidden, the road may partially disappear even if both end points are visible. However, in the second embodiment, it is possible to simplify the arithmetic processing by determining whether or not to draw the entire line segment by determining the visibility of only the end points. It is possible to avoid the phenomenon of interruption.

The operation of the navigation system of the second embodiment having the above configuration will be described based on the flowcharts of FIGS. 18 and 19. The display target area determination unit 3-1 in the arithmetic processing device 3 determines the display target area, and the altitude change area determination unit 3-5 determines the altitude change area (step S1).
-2 reads the terrain data to model the terrain shape (step S2), the display reference point elevation determination unit 3-3 determines the display reference point elevation value (step S3), and the viewpoint coordinate determination unit 3-4. The viewpoint coordinates are determined by (step S
4) Furthermore, the terrain shape is re-modeled by changing the elevation value of the elevation change area around the display reference point with respect to the terrain shape model modeled by the terrain shape modeling section 3-2 by the terrain shape elevation changing section 3-6. The procedure until conversion (step S5) is the same as the procedure of the first embodiment shown in the flowchart of FIG.

After these processes, the map element elevation determining unit 3-7 'displays the display determined by the display target area determining unit 3-1 like the map element elevation determining unit 3-7 of the first embodiment. Map data 2b in the external storage device 2 based on the target area
The map element data such as roads and place names in the display target area is read from, and if there is no elevation value data, the corresponding elevation value is determined by interpolation similarly to the calculation procedure of the display reference point elevation value (step. S6 ').

Subsequently, the coordinate transformation unit 3-8 'executes perspective projection transformation in the same manner as the coordinate transformation unit 3-8 of the first embodiment, and the above-mentioned homogeneous coordinate T = obtained as a result of the transformation.
For (Tx, Ty, Tz, Tw), the two-dimensional coordinates (Sx, Sy) used for drawing are Sx = Tx / Tw, Sy
= Ty / Tw. However, in the case of this embodiment, the depth coordinate Sz is not obtained (step S
7 ').

Next, the terrain shape drawing processing unit 3-10 draws the polyhedron representing the terrain shape remodeled by the terrain shape elevation changing unit 3-6 in the overwrite mode in order from the back side to the viewpoint. The image is processed and displayed on the image display device 4. At this time, the drawing color is changed according to the altitude value (step S1).
0).

Further, the map element elevation comparison unit 3-11 and the map element drawing processing unit 3-12 cooperate with each other to judge whether or not each map display element in the display target area is a place name or the like (step S11), if it is data including a representative point such as a place name and a character string, the elevation value of the representative point is compared with the elevation value of the terrain in the two-dimensional coordinates of the representative point (step S12), and the representative point When the altitude value is larger, the map element such as the character string assigned to the representative point is overwritten on the topographical shape (step S13).

If it is determined in step S11 that the map element is not a place name or the like, then it is determined whether the map element is a line figure such as a road, river, or railway (step S14).
In the case of a line figure, the elevation value of each of the end points 1 (one end point) and the end point 2 (the other end point) of each link is compared with the elevation value of the terrain of the corresponding two-dimensional coordinate (step S1
5, S16), when both end points are equal to or greater than the elevation value of the terrain, the map display element of this line figure is overwritten on the terrain display (step S17).

Further, if it is determined in step S14 that the map element is not a line figure, it is a plane figure representing a lake, river or station facility with a wide basin, golf course or other water system, facility. It is determined whether or not all of the vertices 1 to n of the small polygon divided by the method shown in (4) are equal to or higher than the elevation value of the terrain (steps S18-1 to S18-1).
18-n), if any of the vertices 1 to n is equal to or larger than the elevation value of the terrain, the map display element of the surface figure is overwritten on the terrain display (step S19).

Then, the above steps S11 to S19 are repeatedly executed for all the map elements included in the display target area. Also, the display reference point mark such as the own vehicle position mark is displayed in accordance with the display of this map element (step S110). As a result, a three-dimensional bird's-eye view display of a road map can be displayed on the screen of the image display device 4 as in the first embodiment.

Further, in step S111, it is determined whether or not to continue the map display.
Return to step 1 and repeat the procedure for creating and displaying the next screen. If the process is not continued, the above-described series of processing procedures are ended, and the process is moved to another process of the navigation system such as vehicle position detection and route calculation.

As described above, according to the second embodiment of the present invention, the terrain three-dimensionally represented based on the elevation value data and the map data of the actual terrain shape as in the first embodiment. It is possible to create and display a 3D map with map display elements on top of the shape, display a map that gives the user a strong sense of reality, and intuitively check the current position and the relationship with the surrounding environment. In addition to this, since the change correction is performed so that the altitude of the sampling points that belong to the altitude change area near the display reference point is closer to the display reference point, it should be closer to the viewpoint than the display reference point. Even in the situation where there is a high mountain in the sky and the display reference point is hidden from the view point and the display reference point cannot be seen, it becomes possible to always display the area around the display reference point. When using as a display reference point , Will be able to keep track of presence point of the vehicle, utility is improved.

Further, in the case of the second embodiment, since it is not necessary to perform the hidden surface erasing processing which puts a large burden on the CPU, the burden on the CPU is reduced, and the CPU to be mounted on the system is required for practical use. The required performance can be reduced, and the cost can be reduced accordingly. On the contrary, if the system is equipped with a high-performance CPU, the drawing process can be speeded up accordingly. Further, in the case of the second embodiment, it is possible to eliminate the interruption of the line figure of the road or the like due to the approximation error of the terrain shape, and the correct display can be achieved.

In the second embodiment, the terrain shape drawing processing unit 3-10 draws the terrain shape in different drawing colors according to the altitude value, but the terrain shape is also changed. It is also possible to use a drawing color according to the original topographical elevation value of the range. As a result, even if the background is deformed into gentle undulations, it becomes possible to visually grasp the undulations of the terrain by the drawing color.

Next, FIG. 20 shows a third embodiment of the present invention.
It will be described based on. The hardware configuration of the navigation system of the third embodiment is the same as that of the first embodiment shown in FIG.
15 and the second embodiment shown in FIG. 15, except that the data type stored in the external storage device 2 and the configuration of the arithmetic processing function in the arithmetic processing device 3 are changed. Has been.

The external storage device 2 stores the terrain data 2a similar to that of the first embodiment, but the map data includes the terrain, representative point position information such as icons, and incidental information such as place name character strings, and the like. Place name and background data 2b1 for storing position information of map elements represented by surface figures such as water systems and facilities and incidental information such as connection forms, and position information of map elements represented by line figures such as roads, railways, rivers, etc. And additional information such as each attribute and the like are separately stored in the line figure data 2b2.

The arithmetic processing unit 3 has the same display target area determining section 3-1 to topographical shape elevation changing section 3 as in the first embodiment.
-6 is provided. The map element altitude determining unit 3-7 ", the coordinate converting unit 3-8", the drawing processing unit 3-9 ', the line graphic data altitude comparing unit 3-13, and the line graphic are constituent elements different from those of the first embodiment. The data drawing processing unit 3-14 is provided.

Among the new constituent elements, the map element elevation determining unit 3-7 ″ sets the map element data in the display target area to the place name of the external storage device 2, the background data 2b1 and the line graphic data 2.
By reading from b2, if the elevation value is not registered, by using the three sampling points surrounding the representative point as in the display reference point elevation determination unit 3-3, interpolation based on the equations (1) and (2) is performed. This is the part to calculate the corresponding elevation value.

The coordinate conversion unit 3-8 ″ obtains the two-dimensional coordinates (Sx, Sy) on the display screen by perspective projection conversion as in the first embodiment, and the map display elements other than the line graphic data 2b2. That is, the depth coordinate Sz is also obtained for the place name, background data 2b1 and topographical data 2a.

The drawing processing unit 3-9 'displays the image by enabling the hidden surface removal for the data other than the line graphic data, that is, the terrain data, the place name, and the background data by the same processing as that of the first embodiment. This is a part to be displayed on the device 4.

The line figure data altitude comparing section 3-13 uses the second
Similar to the map element elevation comparing unit 3-11 in the embodiment, the elevation value of the end point of each line element of the line graphic data and the terrain elevation value already drawn at the same position on the screen (given by the drawing color) ) Is the part to compare with.

Then, the line graphic data drawing processing unit 3-14
Similarly to the map element drawing processing unit 3-12 of the second embodiment, is a portion for drawing each line element of the line graphic data as usual unless both end points have an elevation value smaller than the ground surface.

Next, the operation of the navigation system of the above-mentioned third embodiment will be described based on the flowchart of FIG. The display target area determination unit 3-1 in the arithmetic processing device 3 determines the display target area, and the altitude change area determination unit 3-5 determines the altitude change area around the display reference point (step S1), and the terrain shape modeling is performed. The terrain data is read by the section 3-2 to model the terrain shape (step S2), and the display reference point elevation determining section 3-
The display reference point elevation value is determined by 3 (step S3),
The viewpoint coordinate determining unit 3-4 determines the viewpoint coordinates, and the terrain shape altitude changing unit 3-6 models the altitude changing area around the display reference point with respect to the terrain shape model modeled by the terrain shape modeling unit 3-2. The procedure up to remodeling the terrain shape by changing the altitude value (step S5) is the same as the procedure of the first embodiment shown in the flowchart of FIG.

After these processes, the map element elevation determining unit 3-7 ″ displays the display determined by the display target area determining unit 3-1 like the map element elevation determining unit 3-7 of the first embodiment. The map element data is stored in the external storage device 2 based on the target area.
The map element data such as roads, place names, etc. in the display target area is read from the place name, background data 2b1 and line figure data 2b2, and if there is no altitude value data, the same as the procedure for calculating the display reference point altitude value. The corresponding elevation value is determined by insertion (step S6 ″).

Subsequently, the coordinate transformation unit 3-8 ″ executes perspective projection transformation in the same manner as the coordinate transformation unit 3-8 of the first embodiment, and the above-mentioned homogeneous coordinates T = obtained as a result of the transformation.
For (Tx, Ty, Tz, Tw), the two-dimensional coordinates (Sx, Sy) used for drawing are Sx = Tx / Tw, Sy
= Ty / Tw, and depth coordinates Sz (= Tz / Tw) are obtained for data other than line figure data (that is, topographic data, place names, background data) (step S7 ″).

Subsequently, the drawing processing unit 3-9 'erases hidden surfaces for data other than line figure data such as topographical data, place names, and background data, as in the drawing processing unit 3-9 of the first embodiment. Is enabled and displayed on the image display device 4 (step S8 ').

Further, the line figure data altitude comparing section 3
-13 cooperates with the line graphic data drawing processing unit 3-14,
End point 1 of each link for each line figure in the display area
The elevation value of each of the end points (one end point) and the end point 2 (the other end point) is compared with the elevation value of the terrain having the corresponding two-dimensional coordinates (steps S20 to S22), and the elevation values of the terrain having both end points are the respective coordinates. If it is larger than this, this line figure is overwritten on the topography, place name, icon, etc. (step S
23).

The above steps S20 to S23 are repeated for all the line figures included in the display target area (step S24).

As a result, a stereoscopic bird's-eye view display of a road map can be displayed on the screen of the image display device 4 as in the first embodiment.

Further, in step S25, it is determined whether or not the map display is continued, and if it is continued, step S1
Return to and repeat the procedure for creating and displaying the next screen. If the process is not continued, the above-described series of processing procedures are ended, and the process is moved to another process of the navigation system such as vehicle position detection and route calculation.

As described above, according to the third embodiment of the present invention, the terrain three-dimensionally represented based on the elevation value data and the map data of the actual terrain shape as in the first embodiment. It is possible to create and display a 3D map with map display elements on top of the shape, display a map that gives the user a strong sense of reality, and intuitively check the current position and the relationship with the surrounding environment. In addition to this, since the change correction is performed so that the altitude of the sampling points that belong to the altitude change area near the display reference point is closer to the display reference point, it should be closer to the viewpoint than the display reference point. Even in the situation where there is a high mountain in the sky and the display reference point is hidden from the view point and the display reference point cannot be seen, it becomes possible to always display the area around the display reference point. When using as a display reference point , Will be able to keep track of presence point of the vehicle, utility is improved.

Further, in the case of the third embodiment, since the line figure of a road or the like can be seen or hidden only by the end points, it is possible to eliminate the discontinuity due to the approximation error of the terrain shape, and the hidden surface of the place name, the icon, etc. Since the drawing process is performed by erasing, even if the representative point is hidden, it can be partially displayed, and the stereoscopic effect can be further enhanced.

Incidentally, also in the third embodiment,
Similar to the first embodiment, the drawing processing unit 3-9 ′ draws the terrain shape in different drawing colors according to the elevation value. However, regarding the portion where the terrain shape is changed, the original terrain in a corresponding range is drawn. A drawing color according to the altitude value may be used.
As a result, even if the background is deformed into gentle undulations, it becomes possible to visually grasp the undulations of the terrain by the drawing color.

Next, FIG. 22 shows a fourth embodiment of the present invention.
~ It demonstrates based on FIG. The hardware configuration of the navigation system of the fourth embodiment is the same as that of the first embodiment shown in FIG.
The configuration of the arithmetic processing function in is changed.

The arithmetic processing unit 3 has the same display target area determining section 3-1 to viewpoint coordinate determining section 3-4 as in the first embodiment.
Is equipped with. The plane display area determination unit 3-1a, the stereoscopic display area determination unit 3-1b, the map element elevation determination unit 3-70, the coordinate conversion unit 3-80, and the stereoscopic map drawing process are constituent elements different from those of the first embodiment. A unit 3-91, a plane bird's-eye view drawing processing unit 3-92, and an image clipping unit 3-93 are provided.

Among the new components, the plane display area determining unit 3-1a sets a predetermined area (first area) including the display reference point for the display area determined by the display area determining unit 3-1.
In the embodiment of the present invention, the same area as the altitude change area shown in FIG. 10) is determined as the plane bird's-eye view display area, and the stereoscopic display area determination unit 3-1b excludes the plane bird's-eye view display area from the display target area. Is a portion for determining the 3D map display area.

Then, the constant altitude value setting unit 3-60 reads out the map display elements within the plane bird's-eye view display area determined by the plane display area determination unit 3-1a from the map data 2b, and the display reference point altitude determination unit 3-3 This is a part for determining and setting the elevation value of the display reference point to the elevation value of the representative point of those map display elements.

The map element elevation determining unit 3-70 executes the same arithmetic processing as the map element elevation determining unit 3-7 of the first embodiment, and reads the map display element in the three-dimensional map display area from the map data 2b. If the elevation value is not registered, the corresponding elevation is obtained by interpolation based on the equations (1) and (2) by using the three sampling points surrounding the representative point as in the display reference point elevation determination unit 3-3. This is the part that calculates the value.

The coordinate conversion section 3-80 is a section for obtaining the two-dimensional coordinates (Sx, Sy) and depth coordinate Sz on the display screen by perspective projection conversion as in the first embodiment.

The three-dimensional map drawing processing unit 3-91 compares depth coordinates for each pixel and updates and draws only those having a depth smaller than the already drawn pixels to enable hidden surface erasing. Is the part that produces
The plane bird's-eye view drawing processing unit 3-92 draws the plane bird's-eye view map at the same altitude value as the display reference point set by the constant altitude value setting unit 3-60 for the map display elements in the plane bird's-eye view display area, and the three-dimensional map drawing processing unit 3-92. The image clipping unit 3-93 is a portion for overwriting the corresponding portion on the created three-dimensional map by 91, and the image clipping unit 3-93 clips the boundary portion between the three-dimensional map image and the plane bird's-eye view image to display the final image signal as an image. This is a part for outputting the composite image to the device 4. Here, different drawing colors are assigned depending on the altitude value, and different drawing colors are also assigned to roads, rivers, place names, and the like. Further, the guide route is assigned a drawing color different from that of a normal road, and a particularly noticeable color such as red, yellow, or blue is assigned.

Next, the operation of the navigation system of the above-mentioned fourth embodiment will be described. As shown in FIG. 23A, the display target area of the terrain data 2a is determined from the display reference point coordinates and the line-of-sight direction angle input by the display target area determination unit 3-1, and the flat display region determination unit 3 is further determined. -1
The plane bird's-eye view display area and the stereoscopic map display area are determined in the display target area by a and the stereoscopic display area determination unit 3-1b.

Then, the terrain shape modeling unit 3-2 reads the terrain data corresponding to the display target area to model the terrain shape, and the display reference point elevation determination unit 3-3 determines the display reference point elevation value. The viewpoint coordinates determining unit 3-4 determines the viewpoint coordinates.

Further, the map element elevation determining unit 3-70 is the first
The same calculation processing as the map element elevation determination unit 3-7 in the embodiment of the present invention is performed, and the map display elements existing in the stereoscopic map display area determined by the stereoscopic display area determination unit 3-1b are stored in the map of the external storage device 2. If there is no elevation value data read from the data 2b, the corresponding elevation value is determined by interpolation similarly to the procedure for calculating the display reference point elevation value, and the coordinate conversion unit 3
Give it to -80. Further, the constant altitude value setting unit 3-60 reads the map display elements belonging to the plane bird's-eye view display area determined by the plane display area determination unit 3-1a from the map data 2b, and displays them as the elevation value of the representative point of each map display element. The display reference point elevation value determined by the point elevation determination unit 3-3 is set and passed to the coordinate conversion unit 3-80.

The coordinate transformation unit 3-80 executes perspective projection transformation, and the above-mentioned homogeneous coordinate T = obtained as a result of the transformation.
For (Tx, Ty, Tz, Tw), the two-dimensional coordinates (Sx, Sy) used for drawing are Sx = Tx / Tw, Sy
= Ty / Tw, and the depth coordinate Sz (= Tz
/ Tw). Then, the three-dimensional map drawing processing unit 3-91
Generates a stereoscopic map image as shown in FIG. 23 (b) with hidden surface removal enabled for the coordinate-converted display map data.

Further, the plane bird's-eye view drawing processing unit 3-92
As shown in FIG. 23 (c), the background is filled with a drawing color conforming to the display reference point elevation value to represent the flat terrain, and the map display is set to the display reference point elevation value by the constant elevation value setting unit 3-60. The plane bird's-eye view is drawn by overwriting the corresponding portion of the element based on the coordinate-converted data by the coordinate conversion unit 3-80. Further, the image clipping unit 3-93 clips the boundary portion between the stereoscopic map image and the plane bird's-eye view image and synthesizes them into the final output image, and the stereoscopic map as shown in FIG. A plane bird's-eye view synthetic road map is displayed on the image display device 4.

As described above, according to the navigation system of the fourth embodiment, similarly to the first embodiment, the terrain shape represented three-dimensionally based on the elevation value data and the map data of the actual terrain shape is displayed. It is possible to create and display a 3D map with map display elements on top, and to display a map that gives the user a strong sense of reality, and to intuitively recognize the current position and the relationship with the surrounding environment. In addition, a plane bird's-eye view is displayed for the area near the display reference point.Therefore, if there is a mountain higher than the display reference point on the viewpoint side, there is a mountain that is higher than the display reference point. Even if the display reference point is hidden behind the display reference point, it is possible to display the area around the display reference point at all times, especially when the position of the own vehicle is set as the display reference point. Always grasp Will be able, utility is improved.

Even if the elevation of the display reference point changes, the amount of calculation can be reduced because the data (terrain shape model, elevation values of map display elements, etc.) in the three-dimensional map display area remains unchanged, and the drawing process Speed is improved.

In the fourth embodiment, the three-dimensional map drawing processing unit 3-91 draws the three-dimensional map by the hidden surface removal processing, but instead of this, as in the second embodiment. You may make it draw by overwrite processing.

Further, the plane bird's-eye view drawing processing unit 3-92
Instead of filling the background with the drawing color according to the display reference point elevation value, the background may be painted with a drawing color that changes according to the original topographical elevation value in the corresponding range. In this case, even though the background is a flat surface, it is possible to visually grasp the appearance of the terrain by the drawing color. Furthermore, although the navigation system has been described in the above first to fourth embodiments,
Various processing function units incorporated in the arithmetic processing unit 3 of these navigation systems are incorporated into the internal storage device as software programs, or stored as an application software program in an appropriate storage medium to be used by the arithmetic processing unit 3 at the time of use. It is possible to adopt a method in which it is read into an internal storage device and executed.

[Brief description of drawings]

FIG. 1 is a functional block diagram of a first embodiment of the present invention.

FIG. 2 is a flowchart of map display processing according to the above embodiment.

FIG. 3 is an explanatory diagram showing an example of a terrain data structure in the above embodiment.

FIG. 4 is an explanatory diagram showing another example of the terrain data structure in the above embodiment.

FIG. 5 is an explanatory diagram showing a structure of surface graphic data in the above embodiment.

FIG. 6 is an explanatory diagram showing a principle of determining a viewpoint and a display target area in the above embodiment.

FIG. 7 is an explanatory diagram showing modeling of a terrain shape in the above embodiment.

FIG. 8 is an explanatory diagram showing a method of calculating an elevation value of a display reference point in the above embodiment.

FIG. 9 is an explanatory diagram showing an example of setting an altitude change area in the above embodiment.

FIG. 10 is an explanatory diagram showing a remodeling process of a terrain shape model by a terrain shape elevation changing unit in the above embodiment.

FIG. 11 is an explanatory diagram showing a display example of a polyhedron shape created based on the terrain data in the above embodiment.

FIG. 12 is an explanatory diagram showing another display example of the polyhedral shape created based on the terrain data in the above embodiment.

FIG. 13 is an explanatory diagram showing a change in place name display due to movement of a viewpoint in the above embodiment.

FIG. 14 is an explanatory diagram showing an example in which the display reference point is hidden by the high terrain around it because the elevation change area is not set by the stereoscopic bird's-eye view map drawing process.

FIG. 15 is a functional block diagram of a second embodiment of the present invention.

FIG. 16 is an explanatory diagram showing the principle of stereoscopic bird's eye view display in the above embodiment.

FIG. 17 is an explanatory diagram showing a display process of a hidden portion of a road in the above embodiment.

FIG. 18 is a flowchart of the former stage of the map display processing according to the above embodiment.

FIG. 19 is a flowchart of a latter stage of the map display process according to the above embodiment.

FIG. 20 is a functional block diagram of a third embodiment of the present invention.

FIG. 21 is a flowchart of map display processing according to the above embodiment.

FIG. 22 is a functional block diagram of a fourth embodiment of the present invention.

FIG. 23 is an explanatory diagram of drawing processing according to the above-described embodiment.

FIG. 24 is an explanatory diagram of a display example of a three-dimensional road map obtained by the above embodiment.

FIG. 25 is an explanatory diagram showing a conventional bird's-eye view display.

[Explanation of symbols]

1 Display reference point input device 2 External storage device 2a Topographic data 2b Map data 3 arithmetic processing unit 4 Image display device 3-1 Display target area determination unit 3-1a Flat display area determination unit 3-1b Stereoscopic display area determination unit 3-2 Terrain shape modeling section 3-3 Display reference point altitude determination unit 3-4 Viewpoint coordinate determination unit 3-5 Elevation change area determination unit 3-6 Terrain shape elevation change section 3-7, 3-7 ', 3-7 "Map element elevation determination unit 3-8, 3-8 ', 3-8 "coordinate conversion unit 3-9, 3-9 'Drawing processing unit 3-10 Terrain shape drawing processing unit 3-11 Map element elevation comparison section 3-12 Map element drawing processor 3-13 Line figure data altitude comparison section 3-14 Line graphic data drawing processing unit 3-60 Constant elevation value setting section 3-70 Map element elevation determination unit 3-80 Coordinate conversion unit 3-91 3D map drawing processing unit 3-92 Plane bird's-eye view drawing processing unit 3-93 Image clipping unit

─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-9-138136 (JP, A) JP-A-4-133183 (JP, A) JP-A-5-203457 (JP, A) JP-A-8- 44996 (JP, A) JP 5-101163 (JP, A) JP 6-195436 (JP, A) JP 8-189838 (JP, A) JP 7-249114 (JP, A) JP-A-3-75682 (JP, A) JP-A-5-120410 (JP, A) JP-A-8-179688 (JP, A) JP-A-5-46080 (JP, A) JP-A-7-190792 (JP, A) JP-A-8-124095 (JP, A) JP-A-7-220055 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G09B 29/00-29 / 14 G01C 21/00 G06T 17/50 G08G 1/0969

Claims (22)

(57) [Claims] 1. A terrain data storage means for storing terrain shape data capable of giving elevation values to terrain plane coordinates, and position information and incidental information of map display elements such as roads and place names displayed on a map. Map data storage means to be stored, display reference point position coordinates for determining the position and direction of the displayed map, display reference point etc. input means, and input from the display reference point etc. input means Display target area determination means for determining a target area (display target area) on the map displayed on the screen in accordance with the displayed reference point position coordinates and the line-of-sight direction angle, and the display target area determined by the display target area determination means. Elevation change region for the display target region, which determines the altitude change region according to a preset rule based on the relationship between the input display reference point and the line-of-sight direction angle. A terrain shape that determines the terrain shape data of the sampling points belonging to the display target area determined by the display target area determining means from the terrain data storage means, and uses the terrain shape data to model the shape of the terrain. Display reference point elevation determination for determining the elevation value of the display reference point from the modeling means, the display reference point position coordinates input from the display reference point etc. input means, and the terrain shape model obtained by the terrain shape modeling means. Means and sampling points belonging to the altitude change area determined by the altitude change area determination means, the altitude value of the corresponding point of the topographical shape modeled by the topographical shape modeling means by the display reference point altitude determination means Make a change to approach the altitude value of the determined display reference point,
Topographic shape elevation changing means for remodeling the topographic shape, display reference point position coordinates and line-of-sight direction angles input from the display reference point input means, and display determined by the display reference point elevation determining means Viewpoint coordinate determining means for determining perspective coordinates for perspective projection conversion from the reference point elevation value, and a map display element corresponding to the display target area is read from the map data storage means, and the topographical shape elevation changing means as necessary. Map element elevation determining means for determining the elevation value of each map display element based on the terrain shape model remodeled by, and the viewpoint coordinates determined by the viewpoint coordinate determining means and the map coordinates Perspective projection conversion of the terrain shape model and the map display element for which the elevation value has been determined based on the line-of-sight direction angle input from input means such as a display reference point. Coordinate conversion means, a drawing processing means for drawing a stereoscopic map image of the display target area based on the data perspective-transformed by the coordinate conversion means, and an image display means for displaying the stereoscopic map image. Consisting of a navigation system. 2. The navigation system according to claim 1, wherein the drawing processing unit draws the data that has been perspective-projection converted by the coordinate conversion unit while performing hidden surface removal. 3. The navigation system according to claim 1, wherein the drawing processing unit draws the guide route in a drawing color or line type different from that of an ordinary road. 4. The drawing processing means, when drawing the terrain shape, changes the drawing color according to the elevation value of the terrain, and when the terrain shape is remodeled by changing the elevation value. The navigation system according to any one of claims 1 to 3, wherein the drawing color is changed according to the altitude value before the change. 5. Topographical data storage means for storing topographical shape data capable of giving elevation values to topographical plane coordinates, and position information and incidental information of map display elements such as roads and place names displayed on a map. Map data storage means to be stored, display reference point position coordinates for determining the position and direction of the displayed map, display reference point etc. input means, and input from the display reference point etc. input means Display target area determination means for determining a target area (display target area) on the map displayed on the screen in accordance with the displayed reference point position coordinates and the line-of-sight direction angle, and the display target area determined by the display target area determination means. Elevation change region for the display target region, which determines the altitude change region according to a preset rule based on the relationship between the input display reference point and the line-of-sight direction angle. Determining means, and a sampling point group having a predetermined density is set in the display target area determined by the display target area determining means, and the elevation value z corresponding to the plane coordinates (x, y) of each sampling point is set to the topography. A three-dimensional sampling point (x, y, z) group is read from the data storage means, and the three-dimensional sampling point group is connected by ridge lines according to a predetermined rule to create an open polyhedral terrain shape model. And a display reference for determining the elevation value of the display reference point from the display reference point position coordinates input from the display reference point input means and the topographic shape model obtained by the topography shape modeling means. Point elevation determining means, display reference point position coordinates and line-of-sight direction angles input from the display reference point input means, and display reference point elevation determining means Viewpoint coordinate determining means for determining viewpoint coordinates for perspective projection conversion from the display reference point altitude value determined by the above, and the terrain shape modeling means for sampling points belonging to the altitude changing area determined by the altitude changing area determining means. The elevation value of the corresponding point of the topographical shape modeled by is changed to approach the elevation value of the display reference point determined by the display reference point elevation determining means,
Topographic shape elevation changing means for remodeling the topographic shape, and a map display element corresponding to the display target area is read from the map data storage means, and remodeled by the topographic shape elevation changing means as necessary. The map element elevation determining means for determining the elevation value of each map display element based on the terrain shape model and creating display graphic data, the viewpoint coordinates determined by the viewpoint coordinate determining means, the display reference point, etc. Coordinate conversion means for performing perspective projection conversion between the terrain shape model and the map display element for which the elevation value has been determined based on the line-of-sight direction angle input from the input means, and terrain subjected to perspective projection conversion by the coordinate conversion means. Topographical shape drawing processing means for drawing a polyhedron indicating a shape by overwriting from the surface on the back side with respect to the viewpoint and outputting a stereoscopic map image; Map element elevation comparison means for comparing the elevation value of the display position of each map display element determined by the map element elevation determination means and the elevation value of the corresponding terrain shape, based on the comparison result of the map element elevation comparison means, Map element drawing processing means for drawing the map display element by overwriting on the terrain shape with respect to the terrain shape corresponding to or higher than the corresponding terrain shape, and a stereoscopic map image from the terrain shape drawing processing means, and A navigation system comprising: an image display unit for displaying a composite with a map element image from a map element drawing processing unit. 6. The map element elevation comparing means compares the elevation value of the display position of each of the map display elements with the elevation value of the corresponding terrain shape based on the terrain drawing color. The described navigation system. 7. The map element drawing processing means draws when the map display element is a guide route, with a drawing color or line type different from that when the map display element is a normal road. The navigation system according to claim 5 or 6. 8. The terrain shape drawing processing means changes the drawing color according to the elevation value of the terrain when the terrain shape is drawn, and the terrain shape is remodeled by changing the elevation value. The navigation system according to any one of claims 5 to 7, wherein the drawing color is changed according to the altitude value before the change. 9. A terrain data storage means for storing terrain shape data capable of giving an elevation value to a terrain plane coordinate, and position information and ancillary information for displaying line figures such as roads, rivers and railways on a map. Line graphic data storage means for storing information, position information and additional information for displaying character strings such as place names,
Or, the location name for storing the positional information and the additional information for displaying the surface figure expressed by a polygon such as the background, the background data storage means, and the display reference point position coordinates for determining the position and direction of the displayed map. And a display reference point etc. inputting means for inputting the line-of-sight direction angle, and a target area on the map displayed on the screen according to the display reference point position coordinates and the line-of-sight direction angle inputted from the display reference point etc. input means (display Display target area determining means for determining a target area), and the display target area determined by the display target area determining means is set in advance in the relationship between the input display reference point and the viewing direction angle. The altitude change area determining means for determining the altitude change area according to the rule, and a sampling point group of a predetermined density is set in the display target area determined by the display target area determining means. Then, the elevation value z corresponding to the plane coordinates (x, y) of each sampling point is read from the topographical data storage means to generate a three-dimensional sampling point (x, y, z) group, and this three-dimensional Terrain shape modeling means for creating a polyhedral shape terrain shape model by connecting sampling points by ridgelines according to a predetermined rule, and display reference point position coordinates input from the display reference point input means and the above Display reference point elevation determining means for determining the elevation value of the display reference point from the topographic shape model obtained by the topographic shape modeling means, and sampling points belonging to the elevation changing area determined by the elevation changing area determining means, The elevation value of the corresponding point of the terrain shape modeled by the terrain shape modeling means is the display reference point elevation determining means. Therefore make changes to approach the altitude value of the determined display reference point,
Topographic shape elevation changing means for remodeling the topographic shape, display reference point position coordinates and line-of-sight direction angles input from the display reference point input means, and display determined by the display reference point elevation determining means Viewpoint coordinate determination means for determining perspective coordinates for perspective projection conversion from the reference point elevation value, line graphic data corresponding to the display target area is read from the line graphic data storage means, and the place name and background data storage means are used to read the line graphic data. Read the place name and background data, and determine the display value of each line figure, place name, etc. and the elevation value of each surface figure based on the topographic shape model remodeled by the topographic shape elevation changing means, and display it. Map element elevation determining means for creating graphic data for use, viewpoint coordinates determined by the viewpoint coordinate determining means, and visual point input from the display reference point input means. Coordinate conversion means for performing perspective projection conversion of the topographic shape model and the display graphic data of each map display element for which the elevation value has been determined based on the direction angle, and data for perspective projection conversion by the coordinate conversion means. Of these, topographic data, place names, and background data are drawn while performing hidden surface removal, and a hidden surface removal drawing processing unit that outputs a stereoscopic map image, and each line element of the line graphic data determined by the map element elevation determination unit Based on the comparison result of the line figure data elevation comparing means for comparing the elevation value of the end point of the with the elevation value of the corresponding topographical shape, the elevation value of the end point of the line element of the line figure Is a line figure data drawing processing unit that draws by overwriting on the terrain shape with respect to the terrain shape having the same or larger elevation value than the corresponding terrain shape; Navigation system comprising an image display means for displaying by synthesizing the line drawing image from three-dimensional map image and the line graphic data drawing processing means from the processing means. 10. The map element elevation comparing means compares the elevation value of the display position of each of the map display elements with the elevation value of the corresponding terrain shape based on the terrain drawing color. The described navigation system. 11. The line graphic data drawing processing means, when the line graphic is a guide route, draws with a drawing color different from that when the line graphic is an ordinary road, or with a different line type. The navigation system according to claim 9 or 10, characterized in that. 12. The viewpoint coordinate determining means changes the altitude coordinate value of the viewpoint coordinates according to the display reference point altitude value determined by the display reference point altitude determining means. Navigation system according to any one. 13. The elevation change area determining means sets the display target area determined by the display target area determining means,
The fixed front side area including the display reference point when viewed from the viewpoint is determined as an elevation change area.
The navigation system according to any one of 1 to 12. 14. The elevation change area determining means sets the display target area determined by the display target area determining means,
14. The navigation system according to claim 1, wherein a constant circular area surrounding the display reference point is determined as an elevation change area. 15. The topographic shape elevation changing means determines the elevation calculated by the topographical modeling means with respect to the elevation value (hp) of the display reference point determined by the display reference point elevation determining means. The elevation value (denoted as h) of each sampling point belonging to the area is changed based on the following equation to obtain a new elevation value h.
The navigation system according to any one of 3 above. h ← (h-hp) × α + hp However, 1> α ≧ 0. 16. The hidden surface removal drawing processing means changes a drawing color in accordance with an elevation value of the terrain when drawing the terrain shape, and the terrain shape is remodeled by changing the elevation value. The navigation system according to any one of claims 9 to 15, wherein the drawing color is changed depending on the altitude value before the change. 17. A terrain data storage means for storing terrain shape data capable of giving elevation values to terrain plane coordinates, and position information and incidental information of map display elements such as roads and place names displayed on a map. Map data storage means to be stored, display reference point position coordinates for determining the position and direction of the displayed map, display reference point etc. input means, and input from the display reference point etc. input means Display target area determination means for determining a target area (display target area) on the map displayed on the screen in accordance with the displayed reference point position coordinates and the line-of-sight direction angle, and the display target area determined by the display target area determination means. With respect to the display target area, a flat display area and a stereoscopic display area are set according to a rule preset in relation to the input display reference point and the line-of-sight direction angle. Plane constant to -
The stereoscopic display area determining means and the topographical shape data of the sampling points belonging to the display target area determined by the display target area determining means are read from the topographical data storage means, and the topographical shape data is used to model the shape of the topography. A display reference for determining the elevation value of the display reference point from the terrain shape modeling means to perform, the display reference point position coordinates input from the display reference point input means, and the terrain shape model obtained by the terrain shape modeling means. Point elevation determining means, the display reference point position coordinates and line-of-sight direction angle input from the display reference point etc. inputting means, and the display reference point elevation value determined by the display reference point elevation determining means for perspective projection conversion. Viewpoint coordinate determining means for determining viewpoint coordinates, and determination by the plane / stereoscopic display area determining means from the map data storage means. A map display element corresponding to the determined stereoscopic display area is read, and if necessary, the elevation value of each map display element is determined based on the terrain shape model modeled by the terrain shape modeling means, and a stereoscopic display figure is displayed. Map element elevation determining means for creating data, and a map element corresponding to the flat display area determined by the flat / stereoscopic display area determining means is read from the map data storage means, and determined by the display reference point elevation determining means. A constant elevation value setting means for setting the elevation value substantially equal to the display reference point elevation value to the elevation value of the map display element to create the plane display graphic data, and the viewpoint coordinates determined by the viewpoint coordinate determining means. A stereoscopic display diagram in which the terrain shape model and the elevation value are determined based on the line-of-sight direction angle input from the display reference point and other input means. Coordinate conversion means for performing perspective projection conversion of the data, stereoscopic map drawing processing means for drawing a stereoscopic map image of the display target region based on the data subjected to perspective projection conversion by the coordinate conversion means, and the constant elevation value setting means With regard to the plane display graphic data created by the above, the plane bird's-eye view drawing processing unit that overwrites the drawn image by the three-dimensional map drawing processing unit to display the plane bird's-eye view at the constant elevation value, and the three-dimensional map by the three-dimensional map drawing processing unit. A navigation system comprising: an image and image display means for displaying the plane bird's-eye view map image by the plane bird's-eye view drawing processing means. 18. The navigation according to claim 17, further comprising image clipping means for performing image clipping of a boundary portion between the three-dimensional map image by the three-dimensional map drawing processing means and the two-dimensional bird's-eye view map image by the two-dimensional bird's-eye view drawing processing means. system. 19. The method according to claim 17, wherein both the three-dimensional map drawing processing means and the plan bird's-eye view drawing processing means draw the guide route in a drawing color or line type different from that of an ordinary road. Navigation system. 20. The plane / stereoscopic display area determining unit includes:
With respect to the display target area determined by the display target area determination means, a certain front side area including the display reference point from the viewpoint is determined as a flat display area, and a rear side area is determined as a stereoscopic display area. The method according to claim 17, wherein
Navigation system according to any one of. 21. The plane / stereoscopic display area determining means
The constant circular area surrounding the display reference point is determined as a flat display area and the other areas are determined as stereoscopic display areas with respect to the display target area determined by the display target area determination means. 19. The navigation system according to any one of 19. 22. The plane bird's-eye view drawing processing means, when drawing the plane display area, changes a drawing color of a corresponding area according to an elevation value of an original topographical shape. 21. The navigation system according to any one of 21 to 21.