Digital terrain models
The digital terrain model today is the standard way to represent the surface of the field in digital form. Surface of the field is represented by a mathematical model which is based on the use of proper height network (grid) or the use of a network of irregular triangles (TIN). These models are formed based on the known positions and heights of characteristic points and lines (structural and break lines) surface of the field. Aerial imaging and subsequent processing and digital photogrammetric measurements from images is one of the methods for collecting DTM data, which provides an optimal balance between demands for quality data, on the one hand and efficiency and economy on the other.
DTM is extremely useful for all types of spatial analysis and in the preparation and implementation of projects for the construction of various structures on the surface of the field (visibility analysis, 3D visualization, evaluation of erosion, earthworks, volume calculations...).
Data on the surface of the field to end users can be supplied in digital format as processed collected data (points, line terrain-contour lines), but it is often delivered in the form of a grid or TIN DTM data model. The formats for the delivery of this data are standard CAD and GIS vector formats for points, lines and TIN terrain, or it can be a raster GIS formats for DTM in the form of grid.