DEM 地形描述误差的概率分布特征研究

以黄土丘陵1:1万DEM为基础数据,通过稀疏抽点法获取不同格网点布设位置下的DEM,进而分析不同分辨率DEM中单个地面点和区域地形单元的Et概率分布特征。实验结果表明:对于任意格网分辨率DEM,无论是不同布设方案下的单个地面点,还是区域地形单元,其Et的概率密度均呈现正态分布特征。对于单个地面点,如果以其为中心的3×3DEM格网单元区域以凸地形为主,其Et概率密度呈现出右偏正态分布特征;如果以凹地形为主,则呈现左偏正态分布特征,其他区域则呈现标准正态分布特征。

Probability distribution characteristics of DEM terrain representation error

Taking a 1∶10 000 DEM of loess hill as the source data ,this paper analyzes the probability distribution characteristics of Et for individual points and regional terrain units via getting DEMs with different layout schemes through sparse resampling technique . Experimental results show that :for any resolution of DEM ,the probability density of Et appears in the characteristics of a normal distribution ,no matter it is gotten from individual points or regional terrain units ;for a single ground point ,if located in an area corresponding to 3 × 3 grid cells with this point as the center and this area has mainly a convex terrain on the earth , the probability density of Et shows a right skewed normal distribution . If this area corresponds mainly to a concave surface , the probability density of Et shows a left skewed normal distribution ,and it shows a standard normal distribution for the area with other surface forms .