Method of operating a navigation system to provide road curvature

摘要

A computer implemented method of operating a navigation system to provide road curvature is provided. The method comprises obtaining a plurality of spline control points representing a two-dimensional geometry of a portion a road segment and obtaining data indicating a road grade of the portion of the road segment. The spline control points and data indicating road grade are obtained from a geographic database associated with the navigation system. The method further comprises projecting the spline control points onto a slope provided by the road grade to obtain a representation of a restored true road curvature of the portion of the road segment.