摘要
基于DEM的坡度计算,其误差来源于DEM误差、DEM结构和坡度计算模型。在顾及DEM误差自相关的前提下,对四种DEM坡度计算模型进行了分析和评价。研究表明,三阶不带权差分能给出较高的坡度计算精度;在局部窗口中,格网点数量越多,坡度计算越准确;等权比不等权的坡度计算模型更准确;DEM误差自相关结构形式对坡度计算无影响。进一步的理论分析和试验分析还表明:DEM误差自相关性的存在,不仅能够改善地形分析的精度,也能改善DEM自身精度。
Slope is the most frequently utilized variables in GIS-based terrain analysis and geographical modeling. There have been some analyses of the accuracy of these variables derived from grid-based DEM. With analytical and simulated method, this paper assesses the four slope algorithms that widely apply in currently GIS and terrain analysis software. With the findings of this study, we can draw the following conclusions： ① the 3rd Non Weighted Finite Difference （3FD） slope algorithm can estimate more accurately slope than any other slope algorithms under any circumstance, whether the DEM error is spatial autocorrelated or not; ② The structure of the spatial autocorrelation models is not key for assessing the accuracy of the slope algorithms;③ The accuracy of slope estimated from DEM with error＇ s spatial autocorrelation is better than that from DEM error without autocorrelation. It can be therefore coneluded that the error information about a DEM should not only contain Root Mean Square Error （RMSE） of DEM, but also an estimation of the spatial autocorrelation of the elevation errors.
出处
《测绘学报》
EI
CSCD
北大核心
2008年第2期200-206,共7页
Acta Geodaetica et Cartographica Sinica
基金
国家自然科学基金项目(40571120
40671148)
