中文摘要：

在黄土高原选取代表不同黄土地貌类型的神木、绥德、延川、富县、宜君共5个研究样区，以样区1：1万地形图所建立的DEM为研究对象，分析不同水平分辨率DEM所提取的坡度和坡向的信息量变化规律，提出了基于互信息的精度指标。在每一样区随机选取20个试验样区，得到上述指标与水平分辨率的函数关系，可以根据其反函数由已知指标求得所需要的水平分辨率数值，并且该函数关系在每一样区的16个随机检验样区通过了检验。实例证明，该函数关系可以在保证精度的条件下节约成本，并可以减小数据量。

英文摘要：

We took Shenmu, Suide, Yanchuan, Fu County and Yijun as the five major sample areas, which have different landforms in the Loess Plateau, according to the map scale at 1 ： 10 000 as the DEMs objectly. For each sample area, the variation rules of the information amount of the slope and aspect derived by DEMs with differently horizontal resolutions were analyzed and the index of the mutual information was proposed. The relationship between the index and different horizontal resolutions is obtained in 20 experimental areas. If the index is known, the required horizontal resolution can be calculated according to its inverse function. The relationship model has passed test in 16 randomly selected test areas. The experimental results show that the model can decrease the amount of data and cut down the costs whilst keeping the accuracy.