Constructing a dem from grid-based data by computing intermediate contours

Abstract

We present a technique for creating a digital elevation model (DEM) from grid-based contour data. The method computes new, intermediate contours in between existing isolines. These are found by finding the shortest line segment that connects points on two neighboring contours with differing elevations. The midpoint of the line segment becomes a point on the intermediate contour. The contours are completed by connecting individual points. The new contours are then used as data for successive iterations, until an initial surface is formed. Peaks are computed by Hermite splines that follow the slope trend. Gaussian smoothing is applied to the entire surface or only to newly computed elevations, yielding an approximated or interpolated surface, respectively. The DEMs are tested with quantitative methods, and are shown to compare favorably to well established algorithms.