利用点扩散函数的图像模糊特性,提出了一种利用点扩散函数进行数字高程模型(digital elevationmodel,DEM)尺度转换的方法,即以不同尺度的点扩散函数作为模板,通过其与原始DEM的卷积实现不同分辨率DEM的尺度上推。设计了DEM尺度转换的评价指标,该指标包括高程统计特征、空间自相关特性及地形结构特征等。以陕北和晋中两种不同地形的1∶1万5 m格网分辨率DEM为研究数据,对此方法进行了分析验证,并与常用的最邻近、双线性以及立方卷积等方法进行了对比。
DEM(digital elevation model) and terrain analysis based on DEM are scale-dependant.DEM scale transition that deducting other more scales from a fixed resolution is always met in application such as hydrology,soil science,and geomorphology.We present a new DEM scale transition with point spread function which is of image blur.The presented method is carried out by the spatial convolution between DEM with fixed resolution and simulated point spread functions with different radiuses.Then elevation statistics, contour matching,and autocorrelation are designed to evaluate the transformed DEM. Finally the results achived with the proposed method were compared with the results of nearest neighbor assignment, bilinear interpolation and cubic convolution in the two different study areas. The result shows that the proposed method is effective.