基于GIS的不同精度DEM提取地形指标误差分析——以盐池县南部山区为例

An Uncertainty Analysis of Terrain Features Derived from DEM with Different Precision Based on GIS——Taking the South Mountain Areas of Yanchi County as Example

以1∶5万和1∶10万地形图制作的DEM为研究对象,分别提取地面坡度及坡向、地表粗糙度、沟壑密度、坡长5种地形指标,并进行对比分析。实验样区为盐池县南部山区,基本技术平台为ARC/INFO地理信息系统软件。研究结果表明,两种精度DEM在提取地面坡度与地表粗糙度不同程度存在着误差,提取沟壑密度与坡长存在误差较小。提出了运用地理信息系统软件结合DEM提取沟壑密度与坡长的方法。研究成果对于DEM精度估算与误差纠正有一定的指导意义。

Taking DEMs which were made from the topographic maps of 1∶50 000 and 1∶100 000 map scaled as study cases,five indices including the terrain slope and aspect,soil roughness,ravine density,slope length from DEMs are derived,compared and analyzed.Taking the south mountain area of Yanchi county as a test area and ARC/INFO as a main working platform,the results show different errors can be found in terrain slope and soil roughness derived from two precision DEM,but in ravine density and slope length the difference is not significant.A kind of method is brought forward to derive ravine density and slope length from DEM with geographic information system software.The results of this study can be used to guide the error-rectifying and the accuracy-evaluation of the DEMs in practical applications.