Digital elevation model data analysis using the contact surface area

We present an approach for analyzing digital elevation model (DEM) data using the concept contact surface area and mathematical morphology, DEMs are digital representations of the Earth's surface. Generally speaking a DEM is generated as a uniform rectangular grid organized in profiles. In order to analyze DEM data by means of binary morphology, the models are represented as binary solids composed of regular polyhedrons (voxels). In the content of this work, we use morphological operators to erode DEMs, simplify binary solid data, preserve essential shape characteristics, understand shape in terms of a decomposition, and identify object features. This is shown by means of some simple examples. We define the contact surface area for DEMs composed of voxels. The contact surface area corresponds to the sum of the contact surface areas of the neighboring voxels of DEMs. A relation between the area of the surface enclosing the volume and the contact surface area is presented. The definition of contact surface area permits us to obtain a fast and efficient method for plotting models composed of a large number of voxels. (C) 1998 Academic Press.