Method for representing the vertical component of road geometry and computing grade or slope

• US 20060149780A1
• Filed: 12/15/2005
• Published: 07/06/2006
• Est. Priority Date: 10/03/2001
• Status: Active Grant

• Current Assignee: HERE Global B.V. (Nokia Corporation)
• Original Assignee: Rajashri Joshi
• Inventors: Joshi, Rajashri
• Granted Patent: US 7,730,049 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/29 Geographical information databases
• CPC Class Codes: Y10S 707/99933 Query processing, i.e. searching
• CPC Class Codes: Y10S 707/99934 Query formulation, input preparation, or translation

Abstract

A geographic database represents roads including an altitudinal component of the geometry of the roads. The altitudinal component of the geometry of roads is represented using data that indicate straight line segments and vertical curves, in particular parabolic vertical curves. The straight lines and vertical curves are determined by providing data, indicating the altitude at a plurality of locations along portions of roads, as an input to a Hough transform to determine the straight line segments and vertical curves that coincide with the portions of the roads vertically. Then, data that define the straight line segments and vertical curves are stored to represent the altitudinal component of the geometry of the portions of the roads in the geographic database. The altitudinal variation of roads is thus expressed in closed form. From this closed form representation, the slope or grade at any point along the road can be easily computed.

Claims

1. A geographic database stored on a computer readable medium for use with a navigation system, said geographic database comprising:

data representing roads located in a geographic area,

wherein the data representing roads includes data representing the road geometry,

wherein the data representing the road geometry include a horizontal component and an altitudinal component,

wherein the altitudinal component includes data defining straight line segments and vertical curves coinciding vertically with the represented portions of roads, and

wherein said data representing roads may be used by said navigation system to provide a navigation-related feature, wherein said navigation-related feature includes at least one of;

a map display, a route calculation, a route guidance, an adaptive cruise control and an adaptive lighting control.

2. The geographic database of claim 1 wherein the vertical curves are parabolas.

3. The geographic database of claim 1 wherein the horizontal component includes data defining straight line segments and circular arcs coinciding horizontally with the represented portions of roads.

4. The geographic database of claim 1 wherein the data defining said straight line segments and vertical curves comprise parameters.

5. The geographic database of claim 1 wherein the data defining said straight line segments and vertical curves further comprise data indicating end points of the straight line segments and vertical curves.

6. The geographic database of claim 1 wherein said data defining said straight line segments and vertical curves are determined using data indicating altitudes at a plurality of locations along the roads to provide an input to a Hough Transform.

7. The geographic database of claim 6 wherein said data indicating altitudes at said plurality of locations along the roads are obtained using a positioning system located in a vehicle traveling along the roads.

8. The geographic database of claim 7 wherein said vehicle is a probe vehicle.

9. The geographic database of claim 7 wherein said vehicle is operated by a geographic database developer.

10. The geographic database of claim 1 wherein said data indicating altitudes at said plurality of locations along the roads are obtained from maps.

11. A geographic database stored on a computer readable medium for use with a computing platform, said geographic database comprising:

data representing geometry of roads located in a geographic area,

wherein the data representing geometry of roads include a horizontal component and an altitudinal component,

wherein the altitudinal component includes data defining straight line segments and vertical curves coinciding vertically with the represented portions of roads, and

wherein said data representing geometry of roads may be used by said computing platform to provide a navigation-related feature.

12. The geographic database of claim 11 wherein said navigation-related feature is a map display.

13. The geographic database of claim 11 wherein said navigation-related feature is a route calculation.

14. The geographic database of claim 11 wherein said navigation-related feature is a route guidance.

15. The geographic database of claim 11 wherein said navigation-related feature is an adaptive cruise control.

16. The geographic database of claim 11 wherein said navigation-related feature is an adaptive lighting control.

17. The geographic database of claim 11 wherein said data defining said straight line segments and vertical curves are determined using data indicating altitudes at a plurality of locations along the roads to provide an input to a Hough Transform.

18. A computer implemented method of representing roads in a geographic database comprising:

providing data indicating altitudes at a plurality of locations along roads;

using the data indicating altitudes to provide an input to a Hough Transform to determine straight line segments and vertical curves coinciding with the roads vertically; and

storing data representing said straight line segments and vertical curves to represent an altitudinal component of the geometry of the roads in the geographic database.

19. A geographic database formed according to the process of claim 18.

20. The method of claim 18 further comprising:

providing data indicating latitude and longitude at a plurality of locations along the road;

using the data indicating latitude and longitude to provide an input to a Hough transform to determine straight line segments and circular arcs coinciding with the road horizontally; and

storing data defining said straight line segments and circular arcs to represent the horizontal component of the road geometry in the geographic database.