Examination of the SRTM-DEM Subdivision Technique Extracting and Using Topographic Breakline Information

Abstract

The topographic information on the mountainous area is used in many engineering fields. Hydrological analysis is one of these fields. In these application fields, the spatial resolution of DEM is required for analysis specifications. Usually, the spatial resolution of the available DEM data is not sufficient to analyze. However, the ‘SRTM 90m DEM’ produced by NASA, is available over the world wide area. It has a spatial resolution of approximately 90 meter. In this paper, the new technique of the DEM subdivision was examined with practical use. This new technique preserves the topographic breakline. The raster coordinate values of the topographic breakline are extracted first in the new technique. The extracted raster breakline data is converted into vector data. Adding the breakline vector data to the DEM subdivided by mathematical interpolation, the subdivided DEM which preserved the topographic breakline is regenerated. Regenerated DEM was compared with the DEM generated from the scale of 1: 25, 000 topographic maps which have a spatial resolution of 10 meter.