DEM interpolation from contours using medial axis transformation

Contours and digital elevation model (DEM) are the most commonly used digital terrain models. In this paper, we propose a technique for constructing a DEM from contours. The elevation of each ground point in DEM is computed by interpolating the heights of the two adjacent contours of the point. The technique decomposes each sub-domain between adjacent contours into a set of sub-regions using medial axis transformation. Each sub-region in the decomposition is classified into a variety of terrain features like hillsides, valleys, ridges, canyons, peaks, pits, etc. The elevations of points are interpolated with different methods according to terrain features they belong to. The interpolation is conducted on the approximate steepest or shortest slope lines constructed based on medial axis. The univariate monotone rational Hermite spline and convex rational Hermite spline are used for the interpolation.