单流向算法与多流向算法下土壤侵蚀因子的比较研究

Comparison of topographic factors based on single flow direction arithmetic and multiple flow direction arithmetic

本文分别论述了单流向算法与多流向算法下土壤侵蚀因子提取的基本原理、计算模型以及计算流程,并以陕北黄土丘陵区为实验区域,以30m分辨率DEM数据作为基础数据,对比分析了单流向算法与多流向算法下土壤侵蚀因子的空间结构特征与空间数据统计特征。实验结果表明,多流向算法具有与DEM相似的空间结构特征即表面光滑连续特性;空间数据统计分析表明,单流向算法与多流向算法对土壤侵蚀因子的计算影响,在土壤侵蚀因子计算值较小区域有显著性差异。

In the paper, the principles for extracting the topographic factors were expounded and the calculation models and flow chart were suggested, respectively by the methods of single flow direction and the multiple flow direction. By taking the area of Hilly Loess Plateau in northern Shaanxi as an example and the DEM of 30 meter as the basic data, the terrain factors were extracted with the methods of single flow direction and multiple flow direction. And with the spatial structure and spatial statistic analysis of the experimental results, it showed that the method of multiple flow direction was superior to the method sin- gle flow direction for its continuity in the raster surface of the topographic factors, which was in according with the surface of the origin DEM. Meanwhile the two methods for extracting the topographic factors had obvious differences in the low calculating value region.