摘要冲沟是生态系统严重退化的产物,元谋干热河谷冲沟极为发育,冲沟蚕食耕地、造成土地劣化,对土地资源危害很大,构建干热河谷区沟谷的数字高程模型(DEM)对其沟谷侵蚀定量化研究有重要意义。基于ArcGIS 平台,以云南元谋干热河谷区为例,通过野外实测获得高精度、高密度分布采样点高程数据;基于反距离函数插值,以平均误差、均方根误差为指标,通过交叉验证及检查点法,对比分析不同权指数、邻域搜索点数、搜索形状及搜索方位对 DEM 插值的影响。结果表明,权指数为2、椭圆形邻域、邻域点4 ~8 个、四方向插值得到的插值效果最好。构建的 DEM 能够较真实地模拟该地区的形态特征:冲沟汇水面积约0.011 km2 ,区域平均坡度35.37°,最大坡度85.76°, 区域沟壑密度3.95 km/ km2 ,切割深度7 ~12 m。
Abstract：Gully is often the result of serious degradation of ecosystem. In the dry鄄hot velleys the gullies are greatly developed, which destroy cultivated land and have caused serious land degradation and bring severe harms to land resources. Hence, it is meaningful to model terrain morphology DEM based on dry-hot valleys of Yuanmou, especially for the quantitative investigation of soil erosion at gully scale. In this study, high-accuracy and high-density elevation data at sampling points of a typical gully were obtained in Yuanmou by field surveying. Inverse Distance Weighted Method (IDW) interpolation was used to model the terrain surface. Mean error (E1 ) and root mean square error ( E2 ) were used to measure the difference when the weighted index, search points, search shapes and sector types changed. The check points and cross validation were adopted as well. The results showed that we can get the best interpolation effect when the weighted index was 2, neighborhood with 4 - 8 points, and interpolated with four directions. Through setting optimal parameters, the terrain surface can be simulated more actually. DEMs constructed by IDW have shown an ideal depiction of gullies in Yuanmou dry-hot valleys. The main morphological parameters are as follows: the whole area of the watershed is 0.011 km2, the average slope is 35.37°with the maximum 85.76°, and the density of regional gully is 3.95 km/ km2, with the cutting depth ranging between 7 m and 12 m.
2015, Vol. 13 
