关键词: 地形因子, 特征, GIS, 紫色土区, 统计分析

Abstract: In order to explore the specific distribution characteristics of terrain factors in purple soil region, based on ASTER GDEM(30 m resolution ratio), this paper extracted and analyzed the distribution characteristics of terrain factors, including slope gradient, slope length, slope and length factor (LS factor) and gully density, etc. terrain factors by spatial analysis tools of ArcGIS. The results showed that the proportion of steep slope (>15°) was 58% in the whole region, that in Qinba mountain region was the largest, reaching 80%; that in the regions with slope length within the scope of 0~40 cm took 60%, mainly concentrated in Sichuan and Chongqing mountain hilly regions. The proportion with LS factor value >15 was 55%, mainly distributed in Qinba mountain region and Wuling mountain and hilly regions, with the same slope distribution. The gully density of purple soil region was 0.69 km/km2, that in Sichuan and Chongqing mountain and hilly regions were the least, only 0.57 km/km2, being inferior to 17.39% of the average scale gully density value. The results provided scientific basis for soil erosion assessment, soil erosion prediction, and ecological repair and reconstruction in the purple soil regions.

Key words: terrain factor, characteristic, GIS, purple soil region, statistic analysis