Digital terrain models (DTM) have recently become products which substitute standard methods for the terrain relief presentation. As a part of a Geographic Information Systems (GIS) they represent not only a data base related to heights that are used for terrain visualization by the means of interpolation routines for the generation of contours, or terrain presentation by the 3D meshes, but also a useful data base in many GIS and other applications. Numerous users of DTMs should also be supplied with information of DTM quality. This is obtained by the statistical analysis of residuals between generated height and heights of the control points called ground truth. The results of this analysis might be compulsorily part of metadata base for all DTMs products.