Topographic display system

• US 6,448,969 B1
• Filed: 10/06/1999
• Issued: 09/10/2002
• Est. Priority Date: 02/20/1998
• Status: Expired due to Term

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Watanabe, Masaki, Saitou, Hiroshi, Kishi, Norimasa, Minakawa, Rumi
• Primary Examiner(s): Zimmerman, Mark
• Assistant Examiner(s): Padmanabhan, Mano
• Application Number:
  US09/402,543
• Time in Patent Office: 1,070 Days
• Field of Search: 345/421, 345/426, 345/427, 345/428, 345/419, 345/618, 345/7, 345/9, 345/619, 345/648, 701/14, 701/301, 701/213, 701/208, 701/4, 701/8, 340/995, 342/26, 342/33
• US Class Current: 345/428
• CPC Class Codes: G01C 21/3635 Guidance using 3D or perspective road maps
• CPC Class Codes: G06T 17/05 Geographic models
• CPC Class Codes: G09B 29/106 using electronic means
• CPC Class Codes: G09B 29/12 Relief maps relief models G09B25/06

Abstract

In a stereoscopic landform display apparatus disclosed herein, landform data comprising altitude value of landform are stored in an external storage (3), and when a display subject region to be displayed is designated by a display reference point and-the-like output section (5), landform data designated by this display subject region are read from the external storage (3), altitude magnification for emphasizing and displaying undulation state is obtained by a computation unit (1) based on landform data in this region, a computation of a stereoscopic landform image is performed from an altitude value which is multiplied by this altitude magnification, and this stereoscopic landform image is displayed to an image display section (7).

Claims

1. A stereoscopic landform display apparatus comprising:

landform data storing means for storing landform data including altitude value of a landform;

display region designating means for designating a display subject region to be displayed;

computation means which reads said landform data designated by said display subject region from said landform data storing means, obtains altitude magnification for emphasizing and displaying an undulation state of a landform based on said landform data within said region, and performs a computation of a stereoscopic landform image from altitude value which is multiplied by said altitude magnification; and

image display means for displaying said stereoscopic landform image.

2. A stereoscopic landform display apparatus according to claim 1, wherein said computation means comprises:

reference altitude value determining means which reads, from said landform data storing means, said landform data in a range covering said display subject region, and determines altitude value of a reference point displayed in said display subject region based on said landform data;

actual asperity value determining means for determining an actual asperity value indicative of undulation state of said landform based on said landform data which is read;

altitude magnification determining means for determining said altitude magnification in said display subject region based on said actual asperity value;

display altitude value generating means for generating display altitude value by multiplying each altitude value forming said landform data which is read, by said altitude magnification;

display data generating means for generating landform display graphic data which are required for displaying said landform based on said display altitude value;

coordinate conversion means for carrying out coordinate conversion for said landform display graphic data to a stereoscopic landform image; and

drawing processing means for drawing said stereoscopic landform image on said image display means.

3. A stereoscopic landform display apparatus according to claim 2, wherein said actual asperity value determining means determines said actual asperity value using said landform data within a region previously defined in the vicinity of said reference point.

4. A stereoscopic landform display apparatus according to claim 2, wherein said altitude magnification determining means includes input means for inputting a value for designating said altitude magnification, and determines a quotient obtained by dividing said value, which is input, by said actual asperity value as said altitude magnification.

5. A stereoscopic landform display apparatus according to claim 2, wherein said altitude magnification determining means determines said altitude magnification such that said altitude magnification becomes equal to a predetermined value or greater.

6. A stereoscopic landform display apparatus according to claim 2, wherein said drawing means visually draws a shape indicative of degree of said altitude magnification independently from drawing of said stereoscopic landform image.

7. A stereoscopic landform display apparatus according to claim 2, wherein said landform data storing means stores map data including map elements including at least roads and place names, in addition to said landform data;

said display region designating means reads said map element designated by said display subject region from said landform data storing means together with said landform data;

said display data generating means generates display graphic data also with respect to said map element which is read;

said coordinate conversion means carries out coordinate conversion also for said display graphic data; and

said drawing processing means draws said display graphic data which is coordinate converted together with said landform display graphic data.

8. A stereoscopic landform display apparatus according to claim 2, wherein said actual asperity value determining means broadens up to and refers to said landform data possessed by a region which is not displayed around said display subject region, thereby determining said actual asperity value.

9. A stereoscopic landform display apparatus according to claim 8, wherein said actual asperity value determining means broadens said landform data to be referred along an expectable traveling direction, thereby determining said actual asperity value.

10. A stereoscopic landform display apparatus according to claim 2, wherein said altitude magnification determining means determines said altitude magnification using said altitude value at said display reference point, in addition to said actual asperity value.

11. A stereoscopic landform display apparatus according to claim 2, wherein said altitude magnification determining means determines said altitude magnification by referring also to said altitude magnification which was determined in the past.

12. A stereoscopic landform display apparatus according to claim 2, wherein said altitude magnification determining means determines said altitude magnification such that said altitude magnification becomes equal to a predetermined value or less.

13. A stereoscopic landform display apparatus according to claim 1, wherein said computation means comprises;

reference altitude value determining means which reads, from said landform data storing means, said landform data in a range covering said display subject region, and determines altitude value of a reference point displayed in said display subject region based on said landform data;

actual asperity value determining means for determining an actual asperity value indicative of undulation state of said landform based on said landform data which is read;

altitude magnification determining means for determining said altitude magnification in said display subject region based on said actual asperity value;

display altitude value generating means for generating display altitude value by multiplying each altitude value forming said landform data which is read, by said altitude magnification;

landform display color determining means for determining display color of said landform based on said display altitude value;

display data generating means for generating landform display graphic data which are required for displaying said landform based on said display altitude value or said altitude value;

coordinate conversion means for carrying out coordinate conversion for said landform display graphic data to a stereoscopic landform image; and

drawing processing means for drawing said stereoscopic landform image on said image display means using said landform display color.

14. A stereoscopic landform display apparatus according to claim 8, wherein said landform display color determining means determines said display color corresponding to a predetermined lower limit value instead of said display altitude value when said display altitude value becomes extremely small, and determines said display color corresponding to a predetermined upper limit value instead of said display altitude value when said display altitude value becomes extremely great.