分辨率是基于地形测绘数据插值生成DEM的基本问题。利用合适的分辨率既可使生成的DEM如实反映和描述地面地形特征，又可避免引入新误差。基于地貌学原理，以读取基础数据所有信息和有效表达地貌特征为目标，利用多种栅格DEM的坡度均方差 栅格尺寸关系曲线，结合对插值DEM上地貌特征的分析，可以客观地确定地形图插值生成DEM的合适栅格尺寸。系统介绍了这种方法的基本原理，并以黄土高原1∶25万地形图插值生成DEM为例，对该方法的应用进行了讨论。典型地区试验研究表明，黄土丘陵区1∶25万和1∶1万地形图（等高距分别为100 m和5 m）插值生成DEM，DEM的坡度均方差 栅格尺寸关系曲线拐点分别位于50 m和2.5 m处，因而分辨率分别为50 m和2.5 m。本研究可以为改进我国DEM质量提供支持。


It is essential for generating DEM by interpolation from digital topographic datasets to determine an optimal cellsize, with which the basic terrain characteristics can be depicted by the resultant DEM without new errors to be induced. On basis of geomorphological theory, targeting to read all the information from topographic map data, including contours, spot heights and stream- line, and to describe the terrain features efficiently, the breakpoint from steep to flatten in the diagram of the RMS slope and resolutions could be regarded as an optimal resolution. The method was introduced and demonstrated with DEM interpolating based on 1∶250,000 and 1∶10,000 topographic datasets with contour intervals of 100 m and 5 m respectively in loess plateau. The results show that the resolutions for the two scales of topographic maps are 50 m and 2.5 m.