等高线节点密度对DEM精度的影响

Effect of the Node Density of Contour on the Accuracy of DEM

以西南丘陵地区两种比例尺的地形图为数据源,利用GIS软件平台研究不同等高线节点密度下的DEM精度,旨在揭示节点密度对DEM精度的影响。结果表明:不同节点密度所生成的DEM的高程主要差异区域分布在地形结构线附近;当比例尺为1∶2 000和1∶1万,分辨率分别高于2 m和5 m时,节点的变化对DEM的精度并没有明显影响;分辨率低于2 m和5 m时,其理想的节点密度分别约为1/7个/m和1/12个/m,当大于此节点密度时,增加等高线节点并不能改善DEM的质量,反而会降低DEM的精度。

In many cases,contour maps maybe the only source of elevation data at an appropriate scale,which can be available by digitizing.However,few studies have been done on the effect of the node density on the accuracy of DEM.In this paper,taking the contour maps of hilly region in southwest china as data source,using the GIS software,the effect of the node density of contour on the accuracy of DEM was discussed.The results show that：1） The distinction between the DEM interpolated with the contour with different node density mainly exists at the nearby of the structure line of the terrain.2） When the resolution of DEM interpolated with contour at the scale of 1∶2 000 and 1∶10 000 are higher than 2 m and 5 m respectively,there aren＇t significant effect of the node density on the accuracy of DEM.3） However,the resolution are lower than 2 m and 5 m,the best the node density are around 1/7 and 1/12 per meter,the accuracy can＇t be improved by densifying the node when the node density are higher than that