DEM分辨率对地形因子提取影响——以安徽金寨县为例

Influence of DEM Resolution on Extraction of Terrain Factors——A Case Study in Jinzhai County,Anhui

以安徽省金寨县地区1∶50000比例尺的等高线数据,生成不同分辨率的DEM数据,分析在不同分辨率条件下,坡度、坡向、平面曲率和坡面曲率随分辨率的变化情况,并根据信息熵方法,获得这个地区不同分辨率DEM高程熵情况。结果显示,在25 m分辨率下,地形因子的变化基本处于平衡状态;而当上升至50 m时,则存在显著的变动,同时25 m条件下高程信息熵也逐渐降低变化速率。不难发现,案例地区在1∶50000比例尺的等高线下,分析该地区的地形,选取的最佳分辨率是25 m。

Contour data at a scale of 1:50000 in Jinzhai County of Anhui Province were used to generate DEM data at different resolutions and analyzed in the variation of slope,slope direction,plane curvature and slope curvature with resolution for different resolution conditions.According to the information entropy method,the DEM elevation entropy at different resolutions in this region was obtained.The results show that at 25 m resolution,the change of terrain factor is basically in equilibrium.When the resolution rises to 50 m,there are significant changes,and the rate of change of elevation information entropy also gradually decreases at 25 m.The case area was anal-yzed at a 1:50000 scale contour and the best resolution selected for the area's topography is 25 m.