The Method For Extraction Topographic Feature Line Based On Grid DEM

Digital Elevation Model contains a variety of features information of the structure of topographic, such as Ridge and Valley Line. Ridge and Valley Line is the line in undulating terrain changes, but also is the water separation line and the water colletion line. It is not only important significance to study the topography, but also in engineering applications. Due to the structure of the data, grid DEM often did not keep topographical features, such as the current national production of 1:1 million DEM.So the study of automatically extracte the Ridge and Valley line from DEM is become to one of the key problems in Earth Sciences research.This paper aims at the grid DEM producted by to the existing terrain map, and study the extraction method for extraction topographic characteristics.The method for extracting topographical features of the domestic and international situation and study the theory is introduced, the importance of terrain characteristics analysis to is presented, the judgement reason and methods for extraction the topographic feature line is Summarized, the principles and methods of extraction slope, aspect and the curvature based on grid DEM is systematic discussed. The data preprocessing based on grid DEM is researched, and the method for billabong treatment is improved.The author consider that how to efficient and accurate extracte the terrain factor, how to reasonable make decision the classification scheme after captured the terrain factor is the key technique to extraction topographic feature based on grid DEM.The verification of theoretical analysis and experimental method in the paper is approved through the experiment.The contribution of the paper is expresented in the following two points. First, the existing grid DEM data preprocessing is improved, the based on the grid classification and retrieval of the new DEM source data preprocessing algorithms is gived , the searched grid is gived the corresponding treating, so as to reach to no billabong effection.Second, the extracted algorithm based on grid DEM is gived through identification the potential regional of, and combined topographical feature points that use of Split method to achieved, carried out extraction topographical features lines based on grid DEM algorithms finally.This article can be expected that the results of research have a certain reference value on the hydrological analysis, land-use applications areas.