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

• US 6,573,842 B2
• Filed: 09/25/2001
• Issued: 06/03/2003
• Est. Priority Date: 10/06/2000
• Status: Expired due to Term

• 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
• Primary Examiner(s): PHAM, TOAN NGOC
• Application Number:
  US09/962,723
• Publication Number:
  US 20020042674A1
• Time in Patent Office: 616 Days
• Field of Search: 340/995, 340/988, 340/990, 340/961, 701/200, 701/208, 701/210, 701/212, 701/214
• US Class Current: 340/995.14
• 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 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) 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.

2. 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.

3. 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) 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.

4. 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.

5. A map display device, comprising:

a map storing unit operable to store first coordinate information, the first coordinate information showing positions of objects in a map;

a surface generating unit operable to generate 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 unit operable to (a) transform the first coordinate information to second coordinate information on each of the generated surfaces, and (b) map 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 unit operable to perspective-project the mapped images sequentially onto a flat virtual screen to obtain projected images, and display the projected images in sequence.

6. The map display device of claim 5,

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.

7. The map display device of claim 5,

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

the surface generating unit

(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.

8. The map display device of claim 7,

wherein the surface generating unit 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 unit generates the surfaces in accordance with the accepted indications.

9. The map display device of claim 8, further comprising:

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

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

10. The map display device of claim 9,

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.

11. The map display device of claim 10,

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.

12. The map display device of claim 5,

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.

13. The map display device of claim 5,

wherein the mapping performed by the mapping unit is texture mapping.

14. A map display device, comprising:

a map storing unit operable to store first coordinate information, the first coordinate information showing positions of objects in a map;

a surface generating unit operable to generate 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 unit operable to (a) transform the first coordinate information to second coordinate information on each of the generated surfaces, (b) perspective-project 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) display the projected images in sequence.

15. The map display device of claim 14,

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.

16. The map display device of claim 14,

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

the surface generating unit

(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.

17. The map display device of claim 16,

wherein the surface generating unit 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.

18. The map display device of claim 17, further comprising:

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

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

19. The map display device of claim 18,

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.

20. The map display device of claim 19,

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.

21. The map display device of claim 14,

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