DEM对典型喀斯特山区地形及流域特征的尺度效应分析

通过对数字高程模型(DEM)数据进行最近邻方法重采样,获取不同空间尺度DEM数据.针对不同空间尺度DEM,研究地形因子和流域信息提取与DEM的尺度效应,并进行相关性分析.结果表明:1)随DEM空间尺度的增大,高程信息、坡度和地面粗糙度等地形因子的平均值呈下降趋势,河网总长度与河网密度值随DEM空间尺度的增大而减小,大尺度DEM无法较好地表达喀斯特山区细小河流信息;2)经相关性分析发现,坡度、地面粗糙度与DEM分辨率相关性较强,用幂函数拟合相关性为显著相关;3)借鉴信息熵理论方法分析可知,研究区地形和流域信息提取的DEM最佳分辨率范围区间为30~120 m.

Analysis of the Scale Effect of DEM on Topography and Watershed Characteristics in Typical Karst Mountainous Area

Based on the DEM data,the nearest neighbor resampling method was used to obtain different DEM data of different spatial scales. According to the different spatial scales DEM,the topographic factors,the watershed information extraction and the scale effect of DEM and the correlation analysis were investiged. The results showed that:( 1)With the increased of the spatial scale of DEM,the average values of terrain factors,such as elevation,slope and surface roughness,showed a decreasing trend; The total length of the river network and the density of river network decreased with the increase of the spatial scale of the DEM,and the large scale DEM could not express the information of the small rivers in Karst mountain area.( 2) Through the correlation analysis,the correlation between slope,surface roughness and DEM resolution was strong,and the correlation was significantly correlated with power function fitting.( 3) According to the analysis of information entropy theory,the optimal resolution range of DEM was 30~120 m in the study area.