Map display device, map display method, and computer program for use in map display device

• US 20020042674A1
• Filed: 09/25/2001
• Published: 04/11/2002
• Est. Priority Date: 10/06/2000
• Status: Active Grant

• Current Assignee: Godo Kaisha IP Bridge 1 (IP Bridge, Inc.)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Mochizuki, Yoshiyuki, Senda, Keiichi
• Granted Patent: US 6,573,842 B2
• Time in Patent Office: Days
• US Class Current: 701/211
• CPC Class Codes: G01C 21/3635 Guidance using 3D or perspective road maps

Abstract

When a user indicates a portion of a map to be enlarged or contracted, a surface generating unit generates surfaces by gradually changing a surface from a first shape to a second shape, the first shape corresponding to a position of a map portion previously indicated and the second shape corresponding to a position of the map portion currently indicated. A mapping unit maps the map onto the generated surfaces in sequence, to obtain mapped images. A projecting/displaying unit sequentially projects the mapped images onto a flat virtual screen, and displays the projected images. Thus, the desired portion of the map can be enlarged/contracted, while maintaining connections of roads. Also, the map display can be transformed smoothly, even when the target of enlargement/contraction changes from one map portion to another according to the user'"'"'s indications. This helps the user comprehend the contents of the map quickly and accurately.

Claims

1. A map display device, characterized by

(a) generating surfaces with different shapes which are obtained in a process of gradually changing a curvature of a surface with time,

(b) transforming first coordinate information that relates to a map, to second coordinate information on each of the generated surfaces, and

(c) displaying the map in accordance with the second coordinate information on each of the generated surfaces.

2. The map display device of claim 1, comprising:

map storing means for storing the first coordinate information, the first coordinate information showing positions of objects in the map;

surface generating means for generating the surfaces which are obtained in a process of gradually deforming the surface from a first shape to a second shape, the generated surfaces including (a) intermediate surfaces that each have an intermediate shape between the first shape and the second shape and (b) a surface that has the second shape;

mapping means for (a) transforming the first coordinate information to the second coordinate information on each of the generated surfaces, and (b) texture-mapping graphics that represent the objects onto each of the generated surfaces with reference to positions shown by the second coordinate information, to obtain mapped images corresponding to the generated surfaces; and

projecting/displaying means for perspective-projecting the mapped images sequentially onto a flat virtual screen to obtain projected images, and displaying the projected images in sequence.

3. The map display device of claim 2,

wherein the first shape and the second shape are (a) a flat surface and a curved surface, (b) a curved surface and a flat surface, or (c) two curved surfaces.

4. The map display device of claim 2,

wherein a portion of the map that includes a point of interest should be enlarged or contracted gradually with time, and

the surface generating means

(a) generates, when the portion should be enlarged, the surfaces where the second shape is defined such that:

an angle formed between a part of the surface with the second shape to which graphics which represent objects included in the portion are texture-mapped and a line of sight directed to the part of the surface in the perspective projection is larger than any angles formed between other parts of the surface and lines of sight directed to the other parts of the surface in the perspective projection, and

(b) generates, when the portion should be contracted, the surfaces where the second shape is defined such that;

an angle formed between a part of the surface with the second shape to which graphics which represent objects included in the portion are texture-mapped and a line of sight directed to the part of the surface in the perspective projection is smaller than any angles formed between other parts of the surface and lines of sight directed to the other parts of the surface in the perspective projection.

5. The map display device of claim 4,

wherein the surface generating means includes:

a point accepting unit for accepting an indication of a position of the point of interest and an indication regarding whether the portion including the point of interest should be enlarged or contracted, from a user, and

the surface generating means generates the surfaces in accordance with the accepted indications.

6. The map display device of claim 5, further comprising:

altitude storing means for storing altitude information showing a correspondence between positions of points in the map and altitudes of the points,

wherein the mapping means includes;

a surface deforming unit for (a) transforming the positions shown by the altitude information to positions on each of the generated surfaces, and (b) providing undulations corresponding to the altitudes shown by the altitude information, to each of the generated surfaces at the transformed positions, to generate deformed surfaces, and

the mapping means transforms the first coordinate information to the second coordinate information on each of the deformed surfaces.

7. The map display device of claim 6,

wherein the surface deforming unit includes:

an altitude changing unit for changing altitudes in the altitude information that correspond to positions which belong to a first area in the map, to a uniform value, the first area being made up of a current position of the map display device and a neighborhood thereof, and

the surface deforming unit generates the deformed surfaces using the changed altitude information.

8. The map display device of claim 7, wherein the altitude changing unit further changes altitudes in the altitude information that correspond to positions which belong to an area around the first area in the map, in accordance with distances of the positions from the first area.

9. The map display device of claim 2,

wherein when sequentially displaying the projected images, the projecting/displaying means also displays character strings that show the objects, with reference to display positions of the graphics that represent the objects.

10. The map display device of claim 1, comprising:

map storing means for storing the first coordinate information, the first coordinate information showing positions of objects in the map;

surface generating means for generating the surfaces which are obtained in a process of gradually deforming the surface from a first shape to a second shape, the generated surfaces including (a) intermediate surfaces that each have an intermediate shape between the first shape and the second shape and (b) a surface that has the second shape; and

projecting/displaying means for (a) transforming the first coordinate information to the second coordinate information on each of the generated surfaces, (b) perspective-projecting graphics that represent the objects onto each of the generated surfaces which serve as virtual screens with reference to positions shown by the second coordinate information, to obtain projected images corresponding to the generated surfaces, and (c) displaying the projected images in sequence.

11. The map display device of claim 10,

wherein the first shape and the second shape are (a) a flat surface and a curved surface, (b) a curved surface and a flat surface, or (c) two curved surfaces.

12. The map display device of claim 10,

wherein a portion of the map that includes a point of interest should be enlarged or contracted gradually with time, and

the surface generating means

(a) generates, when the portion should be enlarged, the surfaces where the second shape is defined such that:

an angle formed between a part of the surface with the second shape to which graphics which represent objects included in the portion are perspective-projected and a line of sight directed to the part of the surface in the perspective projection is smaller than any angles formed between other parts of the surface and lines of sight directed to the other parts of the surface in the perspective projection, and

(b) generates, when the portion should be contracted, the surfaces where the second shape is defined such that;

an angle formed between a part of the surface with the second shape to which graphics which represent objects included in the portion are perspective-projected and a line of sight directed to the part of the surface in the perspective projection is larger than any angles formed between other parts of the surface and lines of sight directed to the other parts of the surface in the perspective projection.

13. The map display device of claim 12,

wherein the surface generating means includes:

a point accepting unit for accepting an indication of a position of the point of interest and an indication regarding whether the portion including the point of interest should be enlarged or contracted, from a user, and

the surface generating means generates the surfaces in accordance with the accepted indications.

14. The map display device of claim 13, further comprising:

altitude storing means for storing altitude information showing a correspondence between positions of points in the map and altitudes of the points,

wherein the projecting/displaying means includes;

a map deforming unit for (a) calculating altitudes at the positions shown by the first coordinate information, based on the altitude information, and (b) changing the first coordinate information according to the calculated altitudes, and

the projecting/displaying means transforms the changed first coordinate information to the second coordinate information on each of the generated surfaces.

15. The map display device of claim 14,

wherein the map deforming unit includes:

an altitude changing unit for changing altitudes shown by the altitude information that correspond to positions which belong to a first area in the map, to a uniform value, the first area being made up of a current position of the map display device and a neighborhood thereof, and

the map deforming unit changes the first coordinate information in accordance with the changed altitude information.

16. The map display device of claim 15,

wherein the altitude changing unit further changes altitudes shown by the altitude information that correspond to positions which belong to an area around the first area in the map, in accordance with distances of the positions from the first area.

17. The map display device of claim 10,

wherein when sequentially displaying the projected images, the projecting/displaying means also displays character strings that show the objects, with reference to display positions of the graphics that represent the objects.

18. A map display device, characterized by

(a) transforming, when a position of a point of interest on a map is indicated by a user, first coordinate information which relates to the map to second coordinate information on a curved surface whose shape corresponds to the indicated position, and

(b) displaying the map according to the second coordinate information.

19. A map display method, comprising:

a surface generating step for generating surfaces which are obtained in a process of gradually deforming a surface from a first shape to a second shape, the generated surfaces including (a) intermediate surfaces that each have an intermediate shape between the first shape and the second shape and (b) a surface that has the second shape;

a mapping step for (a) transforming first coordinate information to second coordinate information on each of the generated surfaces, the first coordinate information showing positions of objects in a map, and (b) texture-mapping graphics that represent the objects onto each of the generated surfaces with reference to positions shown by the second coordinate information, to obtain mapped images corresponding to the generated surfaces; and

a projecting/displaying step for perspective-projecting the mapped images sequentially onto a flat virtual screen to obtain projected images, and displaying the projected images in sequence.

20. A map display method, comprising:

a surface generating step for generating surfaces which are obtained in a process of gradually deforming a surface from a first shape to a second shape, the generated surfaces including (a) intermediate surfaces that each have an intermediate shape between the first shape and the second shape and (b) a surface that has the second shape; and

a projecting/displaying step for (a) transforming first coordinate information to second coordinate information on each of the generated surfaces, the first coordinate information showing positions of objects in a map, (b) perspective-projecting graphics that represent the objects onto each of the generated surfaces which serve as virtual screens with reference to positions shown by the second coordinate information, to obtain projected images corresponding to the generated surfaces, and (c) displaying the projected images in sequence.

21. A computer-readable program for realizing a map display method on a computer, comprising:

a surface generating step for generating surfaces which are obtained in a process of gradually deforming a surface from a first shape to a second shape, the generated surfaces including (a) intermediate surfaces that each have an intermediate shape between the first shape and the second shape and (b) a surface that has the second shape;

a mapping step for (a) transforming first coordinate information to second coordinate information on each of the generated surfaces, the first coordinate information showing positions of objects in a map, and (b) texture-mapping graphics that represent the objects onto each of the generated surfaces with reference to positions shown by the second coordinate information, to obtain mapped images corresponding to the generated surfaces; and

a projecting/displaying step for perspective-projecting the mapped images sequentially onto a flat virtual screen to obtain projected images, and displaying the projected images in sequence.

22. A computer-readable program for realizing a map display method on a computer, comprising:

a surface generating step for generating surfaces which are obtained in a process of gradually deforming a surface from a first shape to a second shape, the generated surfaces including (a) intermediate surfaces that each have an intermediate shape between the first shape and the second shape and (b) a surface that has the second shape; and

a projecting/displaying step for (a) transforming first coordinate information to second coordinate information on each of the generated surfaces, the first coordinate information showing positions of objects in a map, (b) perspective-projecting graphics that represent the objects onto each of the generated surfaces which serve as virtual screens with reference to positions shown by the second coordinate information, to obtain projected images corresponding to the generated surfaces, and (c) displaying the projected images in sequence.