Map display device and a recording medium

• US 6,282,490 B1
• Filed: 08/06/1998
• Issued: 08/28/2001
• Est. Priority Date: 08/08/1997
• Status: Expired due to Fees

• Current Assignee: Aisin AW Company Limited (Aisin Corp.)
• Original Assignee: Aisin AW Company Limited (Aisin Corp.)
• Inventors: Morimoto, Hirofumi, Nimura, Mitsuhiro, Masuda, Hiroyoshi
• Primary Examiner(s): Nguyen, Tan
• Assistant Examiner(s): Beaulieu, Yonel
• Application Number:
  US09/129,773
• Time in Patent Office: 1,118 Days
• Field of Search: 701/200, 701/208, 701/211, 701/72, 701/23, 701/26, 342/176, 342/178, 342/180, 342/190, 342/191, 340/990, 340/995, 345/133, 345/419, 345/427, 345/438, 345/510
• US Class Current: 340/995.14
• CPC Class Codes: G01C 21/367 Details, e.g. road map scale, orientation, zooming, illumination, level of detail, scrolling of road map or positioning of current position marker
• CPC Class Codes: G08G 1/096827 where the route is computed onboard
• CPC Class Codes: G08G 1/096872 where instructions are given per voice
• CPC Class Codes: G08G 1/096894 where input is assisted by the navigation device, i.e. the user does not type the complete name of the destination, e.g. using zip codes, telephone numbers, progressively selecting from initial letters
• CPC Class Codes: G08G 1/0969 having a display in the form of a map
• CPC Class Codes: G09B 29/106 using electronic means

Abstract

A map display device is presented including an information memory device for storing map data, a display device for displaying a map based on map data stored in the information memory device, and a display control device, which has a coordinate transformation device for transforming coordinates on a curved plane into coordinates on a projected plane, for controlling the readout of map data from the information memory device and the map display on the display device. The display control device relates coordinates on the map to coordinates on the curved plane with respect to a coordinate transformation reference point, transforms coordinates on the curved plane into coordinates on the projected plane using the coordinate transformation device, and displays a map on the display device by using the coordinates transformed on the projected plane. Therefore, the device enables a driver to obtain the same sense of distance unaffected by the direction by using the present position. A map of the vicinity of the present position is displayed over a wide area.

Claims

1. A map display device, comprising:

information memory means for storing map data;

display means for displaying a map based on map data stored in said information memory means; and

display control means for controlling a readout of map data from said information memory means and the map display on said display means, comprising;

coordinate transformation means for transforming coordinates on a curved plane into coordinates on a projected plane,

wherein said display control means relates coordinates on the map to coordinates on the curved plane with respect to coordinates of a coordinate transformation reference point, transforms coordinates on the curved plane into coordinates on the projected plane using said coordinate transformation means, and displays a projected map, based on coordinates transformed on the projected plane, on said display means.

2. The map display device according to claim 1, wherein the curved plane is a spherical plane.

3. The map display device according to claim 1, wherein the curved plane is an oval spherical plane.

4. The map display device according to claim 1, wherein said display control means relates coordinates on a map area within a fixed radius from the coordinate transformation reference point, to the coordinates on the plane and transforms coordinates on the plane into coordinates on the projected plane, and further relates coordinates of the map area which are outside said specified radius to coordinates on the curved plane and transforms coordinates on the curved plane into coordinates on the projected plane.

5. The map display device according to claim 1, wherein said display control means relates coordinates on the map to coordinates on the curved plane which curvature is gradually reduced at every fixed radius around the coordinate transformation reference point, and transforms coordinates on the curved plane into coordinates on the projected plane using said coordinate transformation means.

6. The map display device according to claim 1, wherein said display control means relates only X-coordinates of coordinates on the map below the coordinate transformation reference point to coordinates on the curved plane, and transforms coordinates on the curved plane into coordinates on the projected plane by said coordinate transformation means.

7. A map display device according to claim 1, wherein the curved plane is a partial cone plane.

8. Map display device, comprising:

information memory means for storing map data;

present position detection means for detecting a present position of a vehicle;

display means for displaying a map on the basis of map data stored in said information memory means; and

display control means, which has coordinate transformation means for transforming coordinates on the curved plane into coordinates on the projected plane, for controlling a readout of map data from said information memory means and a map display on said display means,

wherein said display control means relates coordinates on the map to coordinates on the curved plane with respect to coordinates of the present position detected by said present position detection means, transforms coordinates on the curved plane into coordinates on the projected plane using said coordinate transformation means, and displays a projected map based on coordinates transformed on the projected plane, on said display means.

9. The map display device according to claim 8, wherein the curved plane is a spherical plane.

10. The map display device according to claim 8, wherein the curved plane is an oval spherical plane.

11. The map display device according to claim 8, wherein the display control means relates coordinates on a map area within a fixed radius from the coordinate transformation reference point, to the coordinates on the plane and transforms coordinates on the plane into coordinates on the projected plane, and further relates coordinates of the map area which are outside the specified radius to coordinates on the curved plane and transforms coordinates on the curved plane into coordinates on the projected plane.

12. The map display device according to claim 8, wherein the display control means relates coordinates on the map to coordinates on the curved plane which curvature is gradually reduced at every fixed radius around the coordinate transformation reference point, and transforms coordinates on the curved plane into coordinates on the projected plane using the coordinate transformation means.

13. The map display device according to claim 8, wherein the display control means relates only X-coordinates of coordinates on the map below the coordinate transformation reference point to coordinates on the curved plane, and transforms coordinates on the curved plane into coordinates on the projected plane by the coordinate transformation means.

14. A map display device according to claim 8, wherein the curved plane is a partial cone plane.

15. A computer readable recording medium for storing programs, comprising:

a program that relates coordinates on a map to coordinates on a curved plane with respect to coordinates of a coordinate transformation reference point;

a program that transforms coordinates on the curved plane into coordinates on a projected plane; and

a program that displays a projected map based on coordinates transformed on the projected plane.