数字高程模型地形描述精度量化模拟研究

A Simulation on the Accuracy of DEM Terrain Representation

在首先提出数字高程模型 ( DEM)地形描述误差 ( Et)概念的基础上 ,以我国 5个不同地貌类型区为试验样区 ,采用比较分析的方法 ,研究 DEM地形描述误差的成因、影响因素、量测方法以及误差的数学模拟途径。统计分析的结果证明 DEM地形描述误差与 DEM空间分辨率及其地面粗糙度之间存在着线性相关关系 ,回归分析结果显示 ,DEM地形描述误差 Et的均方差 RMS值可以表达为 DEM水平分辨率 ( R)与地面垂直曲率 ( V)的函数 :RMS Et=( 0 .0 0 63 V+0 .0 0 66) R-0 .0 2 2 V+0 .2 41 5。该结果可用以估算所建立的 DEM的地形描述精度 ,也为确定适宜的 DEM分辨率提供了理论依据。

This research puts forward the concept of DEM terrain representation error (Et) first and then investigates the generation, major factors,measurement and simulation of Et. A multi resolution and multi relief comparative approach was used as the major methodology in this study. The experiment reveals a quantitative relationship between the errors and the variation of DEM resolution and terrain roughness at global levels. RMS Et is regressed against the mean profile curvature ( V ) and DEM resolution ( X ) at 6 resolution levels. It is found that the RMS Et may be expressed as RMS Et=(0.006 3 V+0.006 6)R-0.022 V +0.241 5. This founding should be helpful in calculating DEM accuracy, as well as determining the DEM resolution appropriate to the accuracy requirement of a particular application.