Automatic Extraction Of Slope Length And Analyst Based On DEM In The Loess Plateau

Water and soil conservation is always an urgent issue in Loess Plateau. As a very important terrain factor in the research of water and soil loss, slope length, including its concepts, different extraction methods, analyst and research in loess landforms, is an important part in Loess Plateau research. This research was on the basis of summarizing formers' research results and experience extensively. Taking 5m grid cell DEMs as experiment data source, some concepts, types and practical application of slope length are discussed and summarized. Many theories and technological methods like GIS based spatial analyst, quantitively modeling of surface process were utilized to discuss the theories and ways of extracting slope length from DEM, and it attempted to reveal the spatial variation of slope length in North Shaanxi part of Loess Plateau, the influence of development of landforms to slope length and the relationship between slope length and other terrain factors. Firstly, in this research the development of its concepts was reviewed, and its types and some applications were retrospected. And then, two frequently-used methods of extracting slope length from DEM were compared and analyzed, and the suitability of them is discussed in the typical relief of Loess Plateau. The method of validation and elimination errors in the procedure was also given out in this paper. Finally, as well as the slope length variation of different typical samples in North Shaanxi Loess Plateau are studied from south to north, all part Loess Plateau in North Shaanxi was studied with many study areas of typical landforms by means of interpolation and spatial statistic. The causes of its formation are elaborated and analyzed from the directions of the relief configuration and others. Then the effect of slope length along with the development of landform and the relationship with other terrain factors were also studied. This research and some corresponding results provide a concrete foundation and technical support for water conservation project, erosion study and etc. in Loess Plateau.