基于DEM的地形曲率计算模型误差分析

Error analysis on DEM-based terrain curvatures models

地形曲率是地形表面几何形态和地学建模的基本变量之一。本文首先对曲率计算模型进行了归纳,然后通过数据独立的DEM误差分析方法和实际DEM的分析验证,对目前九种曲率计算的三类曲率计算模型进行了量化分析比较。研究结果表明,当DEM数据精度比较高时,高次曲面(四次曲面)能给出较高精度的曲率计算结果,而当DEM误差较大时,低次曲面(二次曲面)由于具有误差的平滑作用而能产生较高精度的曲率值。

Terrain curvature is one of fundamental variables in geomorphology and geoscience modeling.In this paper,the algorithm used to calculate the terrain curvatures is summarized firstly.Then three quantificational algorithms for the nine terrain curvatures used in our study by data-independence DEM and real DEM are analyzed.We found that higher-order local surface(partial quartic surface)can give more accurate results if the DEM elevation data is very accurate.While if elevation data have a relative error,lower-order local surface(quadratic surface),with its smoothness,can give calculate curvatures accurately.