Abstract: This article discusses the algorithm and the flowchart of topographic factors for soil erosion based on grid GIS. Under the environment of ARCGIS grid, the program of computing topographic factors for universal soil loss equation is developed with arc macro language (AML). At the same time, the core codes of the program are supplied. The real application indicates that the precision of the results depends on the precision of data sources.

Key words: Grid GIS; Soil erosion; Universal soil loss equation (USLE); Topographic factors; AML

摘要： 论述了基于栅格GIS 土壤侵蚀地形因子的计算方法和流程，在ARCGIS 栅格模块中利用AML 开发了通用土壤流失方程地形因子的计算程序，并给出了程序核心部分的编码。实际应用表明，计算结果的精度依赖于数据源的精度。

关键词: 栅格GIS；土壤侵蚀；通用土壤流失方程；地形因子；AML