Definition of DTM. History of DTM. Data Sources. TIN and grid data models. Spatial data structures for storing DTM. Creation of digital terrain models. Modifications and tuning DTM. Quality assessment of DTM. Imaging (visualization) DTM and related data. Analytical solutions over the role of DTM: volume calculations, the role of visibility, hydrological analysis, the slope of the terrain and more. Analysis of DTM as a basis for GIS modeling. The use of DTM.