JP2001241957A - System and method for map display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that a sharp elevation difference is generated in the boundary part between a two-dimensional bird's-eye view and a three- dimensional bird's-eye view in a map display system and that underground road data is not displayed. SOLUTION: A reference-elevation-value decision means obtains a reference elevation value on the basis of elevation data belonging to a prescribed region. On the basis of the reference elevation value, an elevation-data change means performs a processing operation in which the elevation of a plane region and that of a three-dimensional region can have continuity. Two-dimensional surface- of-the-earth road data and two-dimensional underground road data are differentiated so as to be stored in a two-dimensional road-data storage means. A three- dimensional road-data generation means generates three-dimensional surface-of- the-earth road data on the basis of the two-dimensional surface-of-the-earth road data and the elevation data, and it generates three-dimensional underground road data on the basis the two-dimensional underground road data and the elevation data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a map display system for displaying map data on a screen, such as a navigation system.

[0002]

2. Description of the Related Art A navigation system is a GPS system.
(Grobal Posistiong System) or a self-contained navigation system to detect the current position of the user, and to display the current position on the screen together with map data of the surrounding area.

In such a navigation system,
Since it is necessary to be able to intuitively grasp the situation to a distant place, various devices have been devised for the screen display mode of the map data. For example, JP-A-7-2200
In the navigation system disclosed in No. 55, map data of a smaller scale is displayed on the screen as the user moves away from the current position, and the map data thus displayed on the screen is subjected to a perspective projection conversion process described later. A bird's-eye view (a map drawn as if viewed from a high place) generated by the application is adopted.

However, since the above-described navigation system uses two-dimensional map data, the map displayed on the screen is always a two-dimensional bird's-eye view. Therefore, there is a problem that it is difficult to grasp the current position on uneven terrain without matching the actual scene.

Therefore, in the navigation system disclosed in Japanese Patent Application Laid-Open No. H10-207356, a distant place is displayed as a three-dimensional bird's-eye view on a screen by using three-dimensional map data. I do.

First, the two-dimensional map data storage means 1
Map data including attribute information and position information on roads, facilities, blocks, nature, place names, and the like is stored, and the position information is represented by two-dimensional coordinates corresponding to latitude and longitude.

The terrain data storage means 2 stores elevation data at intersections of latitudes and longitudes at predetermined intervals. That is, as shown in FIG. 14, points indicated by white circles correspond to intersections of the above-mentioned parallels and meridians at predetermined intervals, and a polyhedron (hereinafter, referred to as a solid) formed by connecting black circles obtained by giving elevation values to the intersections "Mesh-shaped terrain") represents the actual undulation state of the ground surface, that is, the terrain (described later).

Here, when the present position detecting means (not shown) detects the current position of the user, the two-dimensional bird's-eye view generating means 3 and the three-dimensional bird's-eye view generating means 4 are activated, and the perspective projection shown in FIG. Perform conversion processing.

That is, the two-dimensional bird's-eye view generating means 3 first specifies an area to be displayed on the screen as a two-dimensional bird's-eye view (hereinafter, referred to as a “plane area”) (here, specifies an area to be displayed on the lower side of the screen). Two-dimensional bird's-eye view data is generated by extracting map data belonging to this plane area from the map data storage means 1 and then performing perspective projection transformation of the thus extracted map data to a display screen coordinate system.

On the other hand, the three-dimensional map data generating means 23
First, after specifying an area to be displayed on the screen as a three-dimensional bird's-eye view (hereinafter referred to as a “three-dimensional area”) (here, specifying an area to be displayed on the upper side of the screen), map data belonging to this three-dimensional area is stored in the map data storage unit 1 Out of the
Elevation data belonging to this three-dimensional area is taken out from the topographic data storage means 2, and then three-dimensional map data as shown in FIG. 16 is generated based on the map data thus taken out and the elevation data. The three-dimensional map data is perspective-transformed to the display screen coordinate system by the three-dimensional bird's-eye view generating means 4 to generate three-dimensional bird's-eye view data.

When the two-dimensional bird's-eye view data and the three-dimensional bird's-eye view data are generated as described above, the screen display means 5 displays the two-dimensional bird's-eye view data in a plane area on the lower side of the screen and the upper side of the screen. 3D bird's-eye view data is displayed in the three-dimensional area (see FIG. 17).

Further, in the above description, the two-dimensional map data is treated as a single unit including roads, facilities, and the like. However, when the road is mainly handled as in a car navigator,
As described below, road information is superimposed and displayed on the map information displayed as described above.

For example, the two-dimensional road data storage means 21 (which may be included in the two-dimensional map data storage means)
Various kinds of information on roads are stored as two-dimensional road data. The two-dimensional road data includes “point number information” for identifying points (hereinafter referred to as “road constituent points”) constituting roads, "Latitude / Longitude information" expressing the latitude / longitude where the constituent point is located in two-dimensional coordinates (x coordinate / y coordinate) corresponding thereto, for example, "Road type information" indicating the type of road such as National Highway XX It is composed of “connection information” indicating the road composing point to be represented by the point number. For example, FIG.
As shown in (a), point 2 (x, y) = (100, -100) which is connected to point 3 and constitutes National Route 16 is (2, x).
100, -100, ROUTE 16, 3) [point number information, x-coordinate, y-coordinate, road number, point number information of next connection point] and the like.

By the way, on the assumption that the map information is converted into a three-dimensional bird's-eye view as described above, how to overlay the road information on the topographic data becomes a problem.

Therefore, as shown in FIG. 13, the three-dimensional road data generating means 22 first specifies an area to be displayed on the screen based on the current position, and then determines two-dimensional road data belonging to this screen display area. While being taken out from the two-dimensional road data storage means 21, the terrain data belonging to this screen display area is taken out from the terrain data storage means 2, and based on the two-dimensional road data and the elevation data thus taken out, three-dimensional data is obtained. Road data is generated, and the three-dimensional road data is subjected to perspective projection transformation.

In this way, ground surface image data and three-dimensional road image data are generated, and a stomach bird's eye view generating means 4 that scatters them generates a bird's eye view and passes it to a screen display means 5.

As a result, even in the case of a three-dimensional part, an image in which the ground surface image data and the three-dimensional road image data are combined is displayed on a monitor or the like on a screen.

[0018]

However, in the navigation system disclosed in the above-mentioned Japanese Patent Application Laid-Open No. H10-207356, two-dimensional bird's-eye view data is created based only on two-dimensional map data (ie, not based on elevation data). It is generated. That is, the three-dimensional area B
Although the actual altitude value is used as the altitude value of 0, 0 is used for the altitude value of the plane area. As a result, the boundary between the two-dimensional bird's-eye view and the three-dimensional bird's-eye view is
As shown in FIG. 7, there is a problem that a sudden elevation difference occurs.

In the conventional navigation system, three-dimensional road data is generated simply by connecting road constituent points with straight lines. Therefore, as shown in FIG. When there are road constituent points, it is not possible to draw the ground road along the undulation of the mesh terrain. This problem is remarkable in a straight line portion where the density of road constituent points is lower than that in a curved portion such as a curve.

Further, in the above-mentioned conventional navigation system, since the road constituent points are located on the ground surface, it is necessary to draw on the ground surface even on an underground road such as a tunnel, or not to draw the underground road. And it was difficult for the user to see.

The present invention has been proposed based on the above-mentioned conventional circumstances, and has as its object to provide a map display system capable of continuously displaying a two-dimensional bird's-eye view and a three-dimensional bird's-eye view on a screen. It is another object of the present invention to provide a map display system capable of drawing a ground surface road along the undulations of a mesh terrain, and further capable of drawing not only a surface road but also an underground road.

[0022]

The present invention employs the following means to achieve the above object. That is, according to the present invention, as shown in FIG. 1, a planar area represented by two-dimensional coordinates
Of the 2-dimensional bird's-eye view map data obtained by perspective processing, a three-dimensional bird's-eye view obtained by the three-dimensional map data of the three-dimensional region given elevation value at a plurality of positions of map data represented by 2-dimensional coordinates by perspective processing It is assumed that a map display system that displays a screen is used.

Here, the reference elevation value determining means 6 calculates the elevation data belonging to the predetermined area, such as the average value of the elevation data belonging to the plane area and the average value of the elevation data belonging to the boundary area between the plane area and the three-dimensional area B. Is determined as the reference altitude value.

The altitude data changing means 7 changes the altitude difference between the plane area and the three-dimensional area B to a relative height as seen from the user, based on the reference altitude value. That is, the altitude data changing means 7 changes the altitude data belonging to the three-dimensional area B to a value obtained by subtracting the reference altitude value from the altitude data. If the value thus changed becomes a negative value, the negative value is treated as 0.

According to the procedure described above, the two-dimensional bird's-eye view
The two-dimensional bird's-eye view is continuously displayed on the screen (see FIG. 4).

Further, instead of using the standard altitude value as described above, the following processing may be performed. That is, as shown in FIG. The gap formed at the boundary is interpolated so that both have continuity. In this case, the altitude data changing means forcibly makes the altitude value coincide with any altitude between the respective altitude values of the boundary between the plane area side and the solid area side constituting the gap, and The smoothing process is performed so that the amount of change from the original altitude value decreases as the distance from the camera increases.

Next, a method of displaying a three-dimensional road in the map display system will be described below.

That is, in the three-dimensional road data generating means,
Interpolation is performed by giving an altitude to a predetermined position between straight lines connecting road constituent points. As a result, the road information composed of the road composing points follows the terrain data composed of a predetermined rectangle and altitude data such as latitude lines and meridians.

When drawing underground road data, two-dimensional road data storage means distinguishes and stores two-dimensional surface road data and two-dimensional underground road data, and three-dimensional road data generation means The three-dimensional ground data is generated based on the two-dimensional ground road data and the altitude data, and the three-dimensional ground road data is generated based on the two-dimensional ground road data and the altitude data.

Here, the above-mentioned three-dimensional underground road data generating means, when both the start point and the end point of the underground road are known,
Elevation values of road constituent points located in the ground are calculated based on a straight line connecting the start point and the end point. If one of the start point and the end point of the underground road is known, the elevation value of the road composing point located in the ground is calculated based on the elevation value of the ground surface corresponding to the road composing point.

Thus, not only the three-dimensional ground road but also the three-dimensional underground road can be drawn on the display device, and a more convenient map display system for the user can be provided.

[0032]

(Embodiment 1) Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic functional block diagram of a navigation system to which the present invention is applied. Hereinafter, the configuration of the navigation system will be described only for points different from the above-described conventional system.

That is, since the contents stored in the map data storage means 1 and the terrain data storage means 2 and the procedure for generating the two-dimensional bird's-eye view data are the same as those in the above-described conventional art, the description will be omitted. A procedure for generating bird's-eye view data will be described.

First, the reference elevation value determination means 6 retrieves the elevation data belonging to the plane area A shown in FIG. 2 from the topographic data storage means 2 and calculates the average value of the elevation data belonging to this plane area. The average value is passed to the altitude data changing means 7 as the reference altitude value.

Here, after the elevation data changing means 7 retrieves the elevation data belonging to the three-dimensional area B from the topographical data storage means 2, first, the elevation value of the plane area A is made uniform at 0. At the same time, an operation of subtracting the reference altitude value passed as described above from the altitude data belonging to the three-dimensional area B is performed. Therefore, the altitude of the entire three-dimensional area becomes lower by the reference altitude value.

Next, the altitude data (to be described later) adjacent to the plane area in the altitude data which is the result of the operation is changed to “0”, and this change result is passed to the three-dimensional map data generating means 8. For example, among the elevation data “103”, “102”, “104”, and “98” belonging to the three-dimensional area B, “103” and “102” are the elevation data adjacent to the plane area, and the reference elevation value is “ If the altitude data is “100”, the altitude data “103” becomes “0” and the altitude data “1”
02 is “0” and the altitude data “104” is “4”.
The altitude data "98" is changed to "-2" by the altitude data changing means 7 and passed to the three-dimensional map data generating means 8.

The altitude data adjacent to the plane area is the altitude data at a point indicated by a black circle on the boundary α in FIG.

Thereafter, the operation is the same as that of the above-described conventional method except that the above-described change result is used as the elevation data belonging to the three-dimensional area B. That is, the three-dimensional map data generation means 8 retrieves the two-dimensional map data belonging to the three-dimensional area B from the two-dimensional map data storage means 1, and then generates a three-dimensional map data based on the map data and the elevation data as the result of the change. Is generated, and the three-dimensional map is perspective-transformed to the display screen coordinate system by the three-dimensional bird's-eye view generating means 4 to generate three-dimensional bird's-eye view data.

According to the procedure described above, for example, FIG.
3B, the reference elevation value is subtracted from the plane area A and the three-dimensional area B as shown in FIG.
The relative elevation value becomes lower, and the two-dimensional bird's-eye view and the three-dimensional bird's-eye view are displayed on the screen continuously (FIG. 4).
reference).

Further, not only the topography of the plane area and the topography of the three-dimensional area are continuous but, for example, when a road extends from the plane area to the three-dimensional area, the road is also displayed in a continuous state.

Although the average value of the elevation data belonging to the plane area A is set as the reference elevation value here, the average of the elevation data belonging to the "boundary area C between the plane area A and the three-dimensional area B" shown in FIG. The value may be used as the reference altitude value. This boundary area can be defined as an area within a predetermined range from the boundary between the plane area A and the three-dimensional area B.

The altitude data “98” belonging to the three-dimensional area B is changed to “−2”. If the altitude data after the change becomes a negative value, the negative value is changed to “0”. It may be changed to ".

Further, the procedure for generating the two-dimensional bird's-eye view data is the same as the above-described conventional one (particularly, the plane area A
May be set to 0), and a procedure for generating two-dimensional bird's-eye view data after giving a reference elevation value to the plane area A may be used. That is, instead of subtracting the reference altitude value from the altitude data belonging to the three-dimensional area B, the same effect as described above can be obtained even if the plane area A is given a uniform reference altitude value.

Further, here, a two-dimensional bird's-eye view is displayed at the lower side of the screen, and a three-dimensional bird's-eye view is displayed at the upper side of the screen. Can be changed by the user. That is, a two-dimensional bird's-eye view can be displayed in a predetermined range (for example, within a radius of 100 m) from the current position of the user, and a three-dimensional bird's-eye view can be displayed farther from the user's current position. In this case, from the viewpoint of improving the processing speed,
The circular plane area C shown in FIGS. 5A and 5B is preferably transformed into a rectangular area R including the circular plane area C. In this case, the rectangular area R facilitates the extraction of position data with the intersection of the latitude line and the longitude line at a predetermined interval as the vertex. Further, as shown in FIG. 5 (a), the rectangle is not limited to the east, west, north and south directions, but a rectangle having the vertex at the intersection of the latitude and the longitude as shown in FIG. 5 (b) is sufficient. .

Further, it is needless to say that the present invention can be applied to any system that displays map data on a screen without using a navigation system.

In the above, the two-dimensional map data obtained from the two-dimensional map data storage means 1 or the elevation data obtained from the terrain data storage means 2 are transmitted via communication.
The data may be input to the reference altitude value setting means 6, the altitude data changing means 7, and the like. As a result, only map data or elevation data of a necessary area is handled, so that the configuration of the system can be simplified.

(Embodiment 2) FIG. 7 is a block diagram showing a configuration of Embodiment 2 of the present invention.

To provide continuity between the plane area A and the three-dimensional area B, there is a method of moving the end point of the three-dimensional area downward on the display screen as shown in FIG. For example attract endpoint a ₁ so as to eliminate the difference in elevation of the end points a ₁ endpoint a ₀ and solid area B of the flat region A in the end point a ₀ side, to place the both points on the end point a _0. Further, the point a ₂ corresponding to the corner of the next mesh in the direction away from the boundary of the three-dimensional region B, and the next point a ₃ ... Are sequentially reduced at a predetermined ratio of the movement amount of the end point a _1. Move it up and down. This allows the plane area A and the three-dimensional area B to have continuity without changing the elevation value of the vertex T ₀ .

The above processing is performed as shown in FIG.
It can be executed by the data changing means 70. That is,
The altitude data changing means 70 includes the altitude data changing means 7.
First, the elevation data belonging to the three-dimensional area B is
After taking out from the data storage means 2, the elevation value of the plane area A is
Set to 0. Then, the end point a of the plane area A₀And three-dimensional area B
End point a₁And altitude difference h₀Is detected. In addition, the altitude
Difference h₀Each interpolation point in the direction away from the boundary based on
Elevation after correction (in this case, the corner of mesh-shaped terrain)
Is calculated. Furthermore, a predetermined distance (mesh
Point a per interval) _Ten-A₁₁, A₂₀-A_{twenty one}... the same process
The values calculated in this way are converted to 3D map data
It will be passed to the generating means 8. Embodiment 3 Hereinafter, Embodiment 3 of the present invention will be described with reference to the drawings.
Therefore, it will be described in detail.

FIG. 8 is a schematic functional block diagram of a navigation system to which the present invention is applied. Hereinafter, the configuration of the navigation system will be described only for points different from the above-described conventional system.

First, the two-dimensional road data storage means 21
It has a two-dimensional surface road data storage means 21a, and stores two-dimensional surface road data composed of road constituent points as shown in FIG. When the contents of this embodiment are implemented simultaneously with the contents of the first embodiment shown in FIG. 1, the two-dimensional road data storage means 21 stores
It may be common to the one-dimensional map data storage unit 1.

On the other hand, as described above, the terrain data storage means 2 stores terrain (mesh-shaped terrain) data in which elevation values at intersections of latitudes and longitudes are given.

Further, the present system has a three-dimensional surface road data generating means 3 for generating three-dimensional surface road data based on the two-dimensional surface road data, and generates three-dimensional surface road data as follows. I do.

That is, as shown in FIG. 11 or FIG. 19, when the two-dimensional road data belonging to the screen display area is road constituent points 71, 72, 73, 74 (that is, points indicated by black squares), Point 71 ・ 72 ・ 73 ・
If the lines 74 are simply connected by a straight line, the ground road cannot be drawn along the undulation of the mesh terrain.

Therefore, the three-dimensional surface road data generation unit 23
a is, as shown in FIG.
The lines 73 and 74 are connected by a straight line, and the intersections 75, 76, 77, 78 and 79 between the straight line and the boundary of the mesh (that is, points indicated by white squares) are interpolated as road constituent points. In this way, as shown in FIG. 12, it is possible to draw a ground road along the undulation of the mesh terrain.

Here, since it is assumed that the terrain data is a mesh terrain, interpolation is performed on the boundary of the mesh. However, the position at which the interpolation is performed is determined according to the form of the terrain data. Good.

As described above, even if a road that follows the shape of the ground surface can be drawn, if the two-dimensional ground surface road data is connected as it is, it will appear on the ground surface up to an underground road such as a tunnel. Therefore, the following configuration and processing are performed.

First, the two-dimensional road data stored in the two-dimensional road data storage means 21 includes an “underground road flag” indicating whether or not the road constituent point is located in the ground by ON / OFF or the like. A configuration is provided. For example, as shown in FIG. 18 (b), point 2 which connects to point 3 and forms National Route 16
If (100, -100) is located underground, this point 2
Is (2,100, -100, ROUTE16,3, O
N) and other two-dimensional underground road data.

If the two-dimensional road data storage means 21 can store the surface road and the underground road separately, the two-dimensional road data is provided with the "underground road flag" as described above. You don't have to. That is, 2
Two-dimensional road data storage 21a for storing two-dimensional underground road data and two-dimensional underground road data storage 21b for storing two-dimensional underground road data If the means 21 is configured, it is not necessary for the two-dimensional road data to have an “underground road flag”.

The three-dimensional road data generating means 23 is provided with a three-dimensional underground road data generating means 23b.
The operation of b will be described.

That is, FIG. 9A shows the x-axis / y-axis / z
FIG. 3 is a yz plan view of a three-dimensional space formed of three axes viewed from the x-axis direction, and two-dimensional road data (road configuration points) belonging to the screen display area includes road configuration points 80 to 83 and an underground road flag OFF; 87 to 89 and road constituent points 84 to 86 with the underground road flag ON. At this time, 3
The three-dimensional underground road data generation unit 23 b
4 (x1, y1) · 85 (x2, y2) · 86 (x3,
y3), the z-coordinate corresponding to the altitude value is given, and the three-dimensional road composing points 84 '(x1, y1, z1) and 85' (x
2, y2, z2) · 86 ′ (x3, y3, z3),
Between the three-dimensional road constituent points 84 'to 85' and 85 'to
The three-dimensional underground road data is generated by connecting 86 'with a straight line.

Here, since the road constituent points 84 and 86 are the starting point and the ending point of the underground road and are located on the ground surface, their elevation values z
Although 1 · z3 can be calculated by a conventional method, a method of calculating the altitude value z2 of the road constituent point 85 located in the ground becomes a problem. That is, what is stored in the terrain data storage means 2 is the same terrain data (altitude value on the ground surface) as the above-mentioned conventional one.
, The elevation value z of the road composing point 85 located underground
2 must be calculated by a new method.

Therefore, in the present invention, when both the starting point and the ending point of the underground road are known (described later), the elevation value of the road constituent point located in the ground is converted into a straight line connecting the starting point and the ending point. The calculation is performed based on this.

That is, the three-dimensional underground road data generation unit 2
3b is a road constituent point 84 which is a starting point of an underground road.
(X1, y1) and the road constituent point 86 which is the end point of the underground road
(X3, y3), a straight line represented by Equation 1 is obtained, and then a point on this straight line and a road composing point 85 (x2, y3)
Find the closest point 90 (x4, y4) from 2),
Using the point 90 (x4, y4), the calculation shown in Expression 2 is performed, and the calculation result “Z” is set as the altitude value z2 of the road composing point 85 (where “A” shown in Expression 2 is The distance between the road constituent points 84 to 90, "B" is the road constituent points 86 to 90
Distance).

[0066]

(Equation 1)

[0067]

(Equation 2) Note that “Z” obtained by Expression 2 is equivalent to three-dimensional road constituent points 84 ′ (x1, y1, z1) and 86 ′ (x3, y3,
z3) on a straight line connecting the point 90 (x4,
This corresponds to the elevation value of a point having the same x coordinate and y coordinate as y4). The elevation value z2 of the road composing point 85 is obtained by such an operation, as shown in the xy plan view of FIG. This is because the point 85 is not always located.

On the other hand, when only one of the start point and the end point of the underground road is known (described later), the elevation value of the road constituent point located in the ground is the elevation value of the ground surface corresponding to this road constituent point. Is calculated based on

For example, as shown in FIG. 10, the elevation values of road constituent points 93 and 94 located in the ground are points 95 and 96 located on the ground surface having the same x-coordinate and y-coordinate, respectively.
Is multiplied by a reduction coefficient (for example, “0.7”).

Note that instead of multiplying the elevation values of the points 95 and 96 by the reduction coefficient, a predetermined number may be subtracted from the points 95 and 96. That is, the method of calculating the elevation value of the road composing point located in the ground may be another method as long as a value smaller than the elevation value of the ground surface corresponding to this road composing point is obtained. .

In the above description, different operations are performed depending on whether or not the start point and the end point of the underground road are known. However, whether or not the known points are known in a work memory (not shown) This indicates whether the start point and end point are stored. That is, the two-dimensional road data storage means 21
Of course, both the start point and end point are stored.
The two-dimensional road data stored in the work memory by the three-dimensional underground road data generation unit 23b is only data necessary for displaying on the screen. Therefore, only one of the start point and the end point may be stored in the work memory. In this case, it is necessary to generate the underground road data without any trouble. You are going to.

As described above, according to the present invention, since the surface road and the underground road are distinguished from each other, not only the underground road but also the underground road can be drawn, and interpolation is performed on the boundary of the mesh. Therefore, the ground road along the undulation of the mesh terrain can be drawn.

[Brief description of the drawings]

FIG. 1 is a schematic functional block diagram of a navigation system to which the present invention is applied.

FIG. 2 is an explanatory diagram of a boundary region.

FIG. 3 is a diagram showing a change in a mesh-shaped terrain;

FIG. 4 is a diagram showing a screen display state in the present invention.

FIG. 5 is a diagram showing a modification of the plane area.

FIG. 6 is an explanatory diagram of the second embodiment.

FIG. 7 is a block diagram showing a configuration of the second embodiment.

FIG. 8 is an explanatory diagram of the third embodiment.

FIG. 9 is a diagram showing a method for generating three-dimensional underground road data (both start and end points are known).

FIG. 10 is a diagram showing a method of generating three-dimensional underground road data (one of a start point and an end point is known).

FIG. 11 is an explanatory diagram of interpolation.

FIG. 12 is a diagram showing a road drawn according to the present invention.

FIG. 13 is a block diagram showing a conventional technique.

FIG. 14 is an explanatory diagram of terrain data (elevation data).

FIG. 15 is an explanatory diagram of perspective projection conversion processing.

FIG. 16 is a conceptual diagram of a mesh-shaped topographic map.

FIG. 17 is a diagram showing a conventional screen display state.

FIG. 18 is an explanatory diagram of two-dimensional road data.

FIG. 19 is a diagram showing roads in a three-dimensional area drawn by a conventional method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Map data storage means 2 Terrain data storage means 3 Two-dimensional bird's-eye view generation means 4 Three-dimensional bird's-eye view generation means 5 Screen display means 6 Reference elevation value determination means 7 Elevation data change means

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) G09B 29/10 G09B 29/10 A (72) Inventor Kenji Nishimura 1006 Kazuma, Kazuma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Hitoshi Araki 1006 Kadoma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Inventor Masato Yuda 1006 Odaka Kadoma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd.

Claims (26)

[Claims] 1. A two-dimensional bird's-eye view obtained by performing a perspective process on map data of a plane area represented by two-dimensional coordinates, and a three-dimensional area obtained by giving elevation values to a plurality of positions of the map data represented by the two-dimensional coordinates. A map display system for displaying a three-dimensional bird's-eye view obtained by perspective processing of the three-dimensional map data on the screen, comprising: a reference altitude value determining means for obtaining a reference altitude value based on altitude data belonging to a predetermined area; A map display system, comprising: altitude data changing means for performing a process of giving continuity to altitudes of a plane area and a three-dimensional area. 2. The map display system according to claim 1, wherein the reference altitude value is a value calculated based on an altitude value of a predetermined area of the plane area. 3. The map display system according to claim 1, wherein said altitude data changing means changes the altitude data belonging to the three-dimensional area to a value obtained by subtracting the reference altitude value from the altitude data. 4. The map display according to claim 3, wherein the altitude data changing means treats the negative value as 0 when the value obtained by subtracting the reference altitude value from the altitude data belonging to the three-dimensional area is a negative value. system. 5. The altitude data changing means changes altitude data belonging to a plane area to the reference altitude value.
The map display system described in. 6. The map display according to claim 2, wherein said elevation data changing means treats a value smaller than the reference elevation value as a reference elevation value when the elevation data belonging to the three-dimensional area is a value smaller than the reference elevation value. system. 7. The map display system according to claim 1, wherein the altitude data changing means changes altitude data adjacent to the plane area to 0 among the altitude data belonging to the three-dimensional area. 8. The map display system according to claim 3, wherein said altitude data changing means changes altitude data adjacent to a plane area among the altitude data belonging to the three-dimensional area to the reference altitude value. 9. The map display system according to claim 1, wherein said reference elevation value determination means determines an average value of elevation data belonging to a plane area as a reference elevation value. 10. The map display system according to claim 1, wherein the reference elevation value determination means determines an average value of elevation data belonging to a boundary area between the plane area and the three-dimensional area as a reference elevation value. 11. The map display system according to claim 3, further comprising operation means for inputting an instruction to transform a plane area into a rectangular area having a vertex at an intersection of a latitude line and a meridian line at a predetermined interval. 12. A two-dimensional bird's-eye view obtained by performing a perspective process on map data of a plane area represented by two-dimensional coordinates, and elevation data are given to a plurality of positions of the map data represented by the two-dimensional coordinates. In a map display system for displaying a three-dimensional bird's-eye view obtained by perspective processing of three-dimensional map data of a three-dimensional area on a screen, a process of interpolating a gap formed at a boundary between the two-dimensional area and the three-dimensional area to have continuity between the two. A map display system, comprising: altitude data changing means for performing the following. 13. The altitude data changing means forcibly matches an altitude value with any altitude between respective altitude values of a boundary between a plane area side and a solid area side constituting the gap, 13. The map display system according to claim 12, wherein smoothing is performed such that the amount of change from the original altitude value decreases as the distance from the boundary increases. 14. The method according to claim 1, wherein said two-dimensional map data or altitude data transferred by communication is used.
The map display system described in. 15. The map display system according to claim 1, wherein road data is continuous in a plane area and a three-dimensional area. 16. A two-dimensional bird's-eye view obtained by performing a perspective process on map data of a plane area represented by two-dimensional coordinates, and a three-dimensional area obtained by giving elevation values to a plurality of positions of the map data represented by the two-dimensional coordinates. A map display method for displaying a three-dimensional bird's-eye view obtained by perspective processing of the three-dimensional map data on a screen, wherein a process of interpolating a gap formed at a boundary between the planar area and the three-dimensional area to have continuity therebetween is performed. A map display method comprising the steps of: 17. A two-dimensional bird's-eye view obtained by performing a perspective process on map data of a plane area represented by two-dimensional coordinates, and a three-dimensional area in which elevation values are given to a plurality of positions of the map data represented by the two-dimensional coordinates. A map display method for displaying a three-dimensional bird's-eye view obtained by perspective processing of the three-dimensional map data on a screen, wherein a reference altitude value setting process for setting altitude data belonging to a predetermined area as a reference altitude value; And an altitude data changing procedure for performing a process of giving continuity to the plane area, the three-dimensional area, and the altitude. 18. A map display system for displaying three-dimensional road data in which elevation data is given to road constituent points represented by two-dimensional coordinates with surrounding terrain and displaying the screen on a screen. 3. A map display system, comprising: three-dimensional road data generating means for giving an altitude to a predetermined position to perform interpolation. 19. A map display system which combines three-dimensional ground road data obtained by giving altitude data to two-dimensional ground road data represented by road constituent points with surrounding terrain data and displays the combined data on a screen. A two-dimensional road data storage means for storing the two-dimensional ground road data and the two-dimensional underground road data separately, based on the two-dimensional ground road data and the elevation data,
A three-dimensional road data generating means for generating three-dimensional underground road data and generating three-dimensional underground road data based on the two-dimensional underground road data and the altitude data; system. 20. The three-dimensional underground road data generating means, when both the starting point and the end point of the underground road are known, connects the elevation value of the road constituent point located underground between the starting point and the end point. The map display system according to claim 19, wherein the map is calculated based on a straight line. 21. The three-dimensional underground road data generating means, when one of a start point and an end point of the underground road is known, associates an elevation value of a road constituent point located underground with the road constituent point. 20. The map display system according to claim 19, wherein the map is calculated based on an elevation value of the ground surface. 22. The three-dimensional underground road data generating means multiplies an altitude value of the ground surface by a predetermined number,
An elevation value of a road component point located in the ground is calculated.
2. The map display system according to 1. 23. The three-dimensional underground road data generation means, by subtracting a predetermined number from the elevation value of the ground surface,
An elevation value of a road component point located in the ground is calculated.
2. The map display system according to 1. 24. Use of the two-dimensional road data or altitude data transferred by communication.
9. The map display system according to 9. 25. A map display method in which three-dimensional road data in which an elevation value is given to a road component point represented by two-dimensional coordinates is combined with the surrounding terrain and displayed on a screen, wherein a straight line connecting the road component points is provided. 3. A map display method comprising: interpolating altitude data at a predetermined position. 26. A map display method in which three-dimensional road data in which an elevation value is given to a road composing point represented by two-dimensional coordinates and surrounding terrain is displayed on a screen. The two-dimensional road data storage means is distinguished from the middle road data and stored in the two-dimensional road data storage means. The three-dimensional ground road data is generated based on the two-dimensional ground road data. A map display method characterized by generating road data.