Hydrologische Anwendungen des digitalen Geländemodelles

Abstract

In this treatise possibilities are tested to extract hydrologically interesting basic terrain features from a digital terrain model (DTM) based on a regular rectangle grid. A method for the automated derivation of river networks and basin delineation as well as the derivation of slope vectors is practically proved. At first the main concepts and terms are discussed. The next part introduces summing up of the water flow as a method to obtain the river network. Catchment areas are defined for river sections (between two neighbouring nodes) and found by 'flooding' the DTM with regard to their weighted affiliation to the river sections. Pit removal is an own task discussed in the next section. Methods are developed that allow for the derivation of a model without pits. These model is then used for obtaining river networks and delineating basins. Then methods are tested to calculate slope vectors. The slope vectors array is implemented within the DTM program package SCOP. It allows for special graphic representations of the terrain. A pyramid structure of the DTM-data is proposed as a very elegant and effective method for working with very large models as well as for working with a DTM at pretty different scales. In the appendix a developing environment is described, that has been developed especially for developing and testing algorithms with raster data. Emphasis was put on the ease of enhancement, high flexibility and the possibility to allocate complex operations within so-called procedures.