What is Digital Elevation Model (DEM)

Both this article, referred to as Article I, and another one, Article II, entitled “Geometric Quality in Geographic Information IFSAR DEM Control”, published in this encyclopedia propose a method to evaluate the geometric integrity of Digital Elevation Models obtained by different techniques. Therefore, the theoretical aspect of the method to evaluate the geometric integrity and different stochastic hypotheses will be presented in both of them. Herein, we consider the classical topographic or aerial photogrammetry stereo images method (included ASTER or SPOT images) and we assume consistent stochastic hypotheses. In the Article II we consider Interferometry SAR (IFSAR) techniques and the stochastic hypotheses are specific according to the particular geometry involved in this technique.