Method and system for computing road grade data

• US 20050125146A1
• Filed: 01/03/2005
• Published: 06/09/2005
• Est. Priority Date: 09/22/2003
• Status: Active Grant

• Current Assignee: HERE Global B.V. (Nokia Corporation)
• Original Assignee: Bishnu Phuyal, Narayanan Alwar, Ole Henry Dorum
• Inventors: Alwar, Narayanan, Dorum, Ole Henry, Phuyal, Bishnu
• Granted Patent: US 7,398,154 B2
• Time in Patent Office: Days
• US Class Current: 701/208
• CPC Class Codes: G06F 16/29 Geographical information databases
• CPC Class Codes: G06T 17/05 Geographic models
• CPC Class Codes: Y10S 707/99943 Generating database or data structure, e.g. via user interface

Abstract

A method of obtaining data for a geographic database is disclosed. Data indicating a plurality of locations along roads including data indicating altitudes at the plurality of locations is provided. Road grade values for a plurality of subsections of the road are computed; each of the subsections is a portion of the road between two of the locations. A plurality of temporary change points are identified as joining two adjacent subsections having road grade values that differ by a value greater than a predetermined amount. Road grade values for each part of the road between adjacent temporary change points are computed. Consecutive parts of the road having road grade values that falls within a predetermined range are grouped into at least one constant road grade section. The geographic database stores data that define the constant road grade section.

Claims

1-19. -19. (canceled)

20. A method of representing road geometry for a geographic database comprising:

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

using the data indicating altitudes and horizontal distance along the road as inputs to a Hough Line Transform to determine a plurality of straight line segments corresponding to a plurality of constant road grade sections along the road; and

storing data that define said constant road grade sections in the geographic database.

21. The method of claim 20 further comprising identifying a grade change point corresponding to a location of an intersection of adjacent straight-line segments determined by the Hough Line Transform.

22. The method of claim 20 further comprising identifying a road grade value of one of said constant road grade sections as a slope of said corresponding straight-line segment.

23. The method of claim 22 further comprising storing said road grade value of said constant road grade section in the geographic database.

24. The method of claim 20 further comprising:

identifying a grade change point corresponding to a location of an intersection of adjacent straight-line segments determined by the Hough Line Transform; and

storing said grade change point in said geographic database.

25. The method of claim 20 wherein said data indicating said plurality of locations along roads including data indicating latitude and longitude at each of said plurality of locations.

26. The method of claim 25 wherein said horizontal distance is calculated from said data indicating latitude and longitude.

27. A method of obtaining data for a geographic database comprising:

providing data indicating latitude, longitude and altitude at a plurality of locations along roads;

performing a Hough Line Transform using said data to determine a plurality of straight line segments corresponding to a plurality of constant road grade sections along the road; and

storing data that identify said constant road grade sections in the geographic database.

28. The method of claim 27 further comprising identifying a grade change point corresponding to a location of an intersection of adjacent straight-line segments determined by the Hough Line Transform.

29. The method of claim 28 further comprising storing said grade change point in the geographic database.

30. The method of claim 27 further comprising identifying a road grade value of one of said constant road grade sections as a slope of said corresponding straight-line segment.

31. The method of claim 30 further comprising storing the road grade value of said constant road grade section in the geographic database.

32. The method of claim 27 wherein the data indicating altitudes and horizontal distances along the road are used as inputs to the Hough Line Transform.

33. The method of claim 32 wherein said horizontal distance is calculated from said data indicating latitude and longitude.

34. A method of obtaining data for a geographic database comprising:

providing data indicating latitude, longitude and altitude at a plurality of locations along roads;

performing a Hough Line Transform using said data to determine a plurality of straight line segments corresponding to a plurality of constant road grade sections along the road, wherein said inputs to said Hough Line Transform are horizontal distance along the road and altitude; and

storing data that define road grade in the geographic database.

35. The method of claim 34 further comprising identifying a grade change point corresponding to a location of an intersection of adjacent straight-line segments determined by the Hough Line Transform.

36. The method of claim 35 further comprising storing said grade change point in the geographic database.

37. The method of claim 34 further comprising identifying a road grade value of one of said constant road grade sections as a slope of said corresponding straight-line segment.

38. The method of claim 37 further comprising storing the road grade value in the geographic database.

39. The method of claim 34 wherein said horizontal distance is calculated from said data indicating latitude and longitude.