Terrain reconstruction from contours by skeleton construction

Generating terrain models from contour input is still an important process. Most methods have been unsatisfactory, as they either do not preserve the form of minor ridges and valleys, or else they are poor at modeling slopes. A method is described here, based on curve extraction and generalization techniques, that is guaranteed to preserve the topological relationships between curve segments. The skeleton, or Medial Axis Transform, can be extracted from the Voronoi diagram of a well-sampled contour map and used to extract additional points that eliminate cases of "flat triangles" in a triangulation. Elevation estimates may be made at these points. Based on this approach it is possible to make reasonable estimates of slopes for terrain models, and to extract meaningful intermediate points for triangulated irregular networks (TINs).