DEM网格尺寸对地形因子精度的影响分析

Analysis on the influence of DEM grid size on the accuracy of topographical factors

本文以四川省为研究区,基于SRTM数据和GDEM数据,选取5种不同网格尺寸提取坡度、坡向、剖面曲率、平面曲率和地表粗糙度等地形因子,比较DEM网格尺寸变化对提取的地形因子计算结果的误差。研究表明,DEM网格尺寸的增大增加了DEM对地形信息的概括,提取的地形因子准确性降低;但是网格尺寸如果过小,会导致数据量快速增大,浪费大量时间和计算机资源。所以在生产实践中,应综合考虑多种因素选择适宜的网格尺寸。

The paper based on the SRTM data and GDEM data, took Sichuan Province as study area, and extracted topographical factors such as slope, aspect, profile curvature, plane curvature and surface roughness from DEM which were five different grid sizes, then compared the errors of topographical factors produced by different grid sizes. The research showed that the larger the grid size was, the simpler the expression of topographic information and the lower accuracy were. ff the grid size was too small, the amount of data would increase rapidly, which was a waste of time and computer resources. As a result, in the production practice many factors should be considered to choose the appropriate grid size.