THE COMBINATION OF GEODETIC AND CLOSE-RANGE PHOTOGRAMMETRY METHODS IN TERRAIN MAPPING FOR THE PURPOSE OF HYDROLOGICAL ANALYSIS IN LAND EROSION PROTECTION

Hydrological analysis represent important input for water erosion identification, which is essential for the land protection against erosion. Soil erosion caused by water presents a dynamic process in the landscape. Basic geomorphological parameters surveyed by geodetic methods within a spatial scale of cadastral district determine a fundamental characteristic of erosion intensity. Geodetic surveys represent classical selective measurement, where the surveyor identifies the main and significant terrain lines and points based on his/her experience. On the other hand, photogrammetry represents standard non-selective method of terrain surveying. Spatial position of arbitrary points is captured usually within a predefined raster of density that is unlimited or limited by ground sample distance (GSD). Result of a photogrammetric processing represents a high density set of spatial points captured within the whole surveying area regardless of changes in terrain elevation. In addition, available high temporal resolution is important in research of erosion threat and subsequent erosion protection, because it allows to determine changing volumetric parameters. The presented work describes possibilities to increase the level of detail for objects surveyed by geodetic measurement by combination with close-range photogrammetry technologies used to determine parameters of digital elevation model (DEM). DEM is a basic element for hydrological analysis in erosion protection. Achieved results show comparable quality of geodetic and photogrammetric data, especially for more precise definition of shapes and geometry of surveyed objects. This enables modeling of dynamic process in land with high resolution accuracy.