When Digital Line Graphic (DLG)is used to generate DEM with interpolation,the qualities of DEMs quite depend on preferred cellsizes.For generation of acceptable landscapes by selection of an optimal one from cellsizes,it would be quite concern of engineers working on remote survey.In this study,for case study,it selected two typical research sites at an undulating hill of northeast China and a loess hill of northwest China,respectively.By using 1∶50 000 DLG,a preferred cellsize was determined by combination of information content analysis and sampling theroem analysis.Then,terrain analysis,contour line overlay analysis and stream network analysis were utilized to evaluate the qualities of the generated DEMs.The results showed that if using 1 ∶ 50 000 DLG for DEM generation,the preferred cellsize of hilly region was 20 m in northeast China,and 10 m in Loess Plateau.This study provides a reference to determine the preferred cellsize to generate appropriate DEM from DLG.%利用数字线划图(Digital Line Graphic,DLG)插值建立数字高程模型(Digital Elevation Model,DEM)时,栅格尺寸影响对所生成的DEM质量,并且不同地形类型区DEM的适宜栅格尺寸应该是不同的,如何确定不同地形类型区适宜的栅格尺寸成为亟须解决的问题.本文以1∶50 000 DLG数据为基础,在东北漫岗丘陵区和黄土丘陵沟壑区选择典型样区,基于信息含量和采样定理两种方法确定DEM适宜栅格尺寸,并通过地形形态分析、等高线套合分析和水文地貌关系分析三种方法对结果进行验证.实验结果表明,基于1∶50 000 DLG建立DEM时,东北漫岗丘陵区适宜栅格尺寸可设为20 m,黄土丘陵沟壑区可设为10 m.本研究为通过DLG插值建立DEM时适宜栅格尺寸的确定提供了参考.
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