Quantitative Analysis of Error in Extracting Slope Length from Grid-Based Digital Elevation Model

As one of the most important variables of topography, the quality of extracting slope length has a serious effect on soil and water conservation, soil erosion and environmental assessment studies. Based on the principle of data independent DEM interpretation analysis method, this paper quantitatively studies the error spatial distribution of slope length which is extracted from grid-based Digital Elevation Model. The result shows that the error of the direct calculation algorithm, which is widely used, is distributed mainly within valley area, and in the catchment area, the result of this algorithm is relatively satisfied.