Method and system for computing road grade data
First Claim
1. A computer-implemented method of representing road geometry for a geographic database comprising:
- providing data indicating a plurality of locations along roads, including data indicating longitude, latitude and altitude at said plurality of locations;
computing a horizontal distance between two of said locations;
using a Hough Line Transform to determine a plurality of straight line segments corresponding to a plurality of constant road grade sections along the road, wherein the Hough Line Transform uses data indicating altitudes and said horizontal distance along the road as inputs;
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 data that define said constant road grade sections in the geographic database.
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Accused Products
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.
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Citations
17 Claims
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1. A computer-implemented method of representing road geometry for a geographic database comprising:
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providing data indicating a plurality of locations along roads, including data indicating longitude, latitude and altitude at said plurality of locations; computing a horizontal distance between two of said locations; using a Hough Line Transform to determine a plurality of straight line segments corresponding to a plurality of constant road grade sections along the road, wherein the Hough Line Transform uses data indicating altitudes and said horizontal distance along the road as inputs; 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 data that define said constant road grade sections in the geographic database. - View Dependent Claims (2, 3, 4, 5)
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6. A computer-implemented method of obtaining data for a geographic database comprising:
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providing data indicating latitude, longitude and altitude at a plurality of locations along roads; performing a Hough Line Transform using said data indicating latitude, longitude and altitude to determine a plurality of straight line segments corresponding to a plurality of constant road grade sections along the road; and storing road grade data that identify said constant road grade sections determined by said Hough Line Transform in the geographic database. - View Dependent Claims (7, 8, 9, 10, 11, 12)
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13. A computer-implemented method of obtaining data for a geographic database comprising:
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providing data indicating latitude, longitude and altitude at a plurality of locations along roads; computing a horizontal distance between two of said locations; performing a Hough Line Transform 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; identifying a road grade value of one of said constant road grade sections as a slope of said corresponding straight-line segment; and storing data that define road grade in the geographic database. - View Dependent Claims (14, 15, 16, 17)
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Specification