地形信息对确定DEM适宜分辨率的影响  

Effects of different topographic attributes on determining appropriate DEM resolution

作　　者：呼雪梅[1,2] 秦承志[1] 

机构地区：[1]中国科学院地理科学与资源研究所资源与环境信息系统国家重点实验室,北京100101 [2]中国科学院大学,北京100049

出　　处：《地理科学进展》2014年第1期50-56,共7页Progress in Geography

基　　金：国家科技支撑计划项目(2013BAC08B03-4);中科院地理资源所优秀青年人才基金项目(2011RC203)

摘　　要：分辨率会直接影响基于栅格数字高程模型(DEM)的数字地形分析结果,因此在实际应用中,需要选择适宜的DEM分辨率。目前采取的基本方法,基于某种地形信息定量刻画尺度效应曲线,从而确定DEM适宜分辨率,但对于采用不同地形信息时所产生的影响尚缺乏研究。本文针对该方法中通常采用的坡度、剖面曲率、水平曲率等3种地形信息,每种地形信息提取时,分别使用两种不同的常用算法,在3个不同地形特征的研究区中,逐一计算其在不同分辨率下的局部方差均值,以刻画尺度效应曲线,确定相应的DEM适宜分辨率,并进行对比分析。结果表明:①采用剖面曲率或水平曲率所得适宜分辨率结果基本相同,但采用坡度所得出的适宜分辨率结果则有明显差别,后者所得的适宜分辨率更粗;②采用不同地形信息时,越是在平缓地形为主的研究区,所得的适宜分辨率结果越相近,在复合地形特征的研究区所得到的适宜分辨率区间均明显较宽;③地形属性计算时所用的算法对适宜分辨率结果的影响不明显。Due to the scale effect of changing resolution for grid-based digital terrain analysis, it is important to determine an appropriate resolution （or a range of appropriate resolutions） for gridded digital elevation model （DEM） in practice. The commonly-used approach to determining appropriate resolutions is based on a scale ef- fect curve characterized by certain types of statistics （the mean of local variance is commonly used）, which is calculated on the multi-resolution dataset of a specific topographic attribute derived from the gridded DEMs with a series of spatial resolutions. The resolution with the highest value of the mean of local variance is consid- ered to be an appropriate DEM resolution. Although several topographic attributes （such as slope gradient and curvature） have been used in this approach, there are few researches on the effects of different topographic attri- butes on the results from this approach. In this paper, we used an experiment to compare the effects of three types of topographic attributes （i.e., slope gradient, profile curvature, and horizontal curvature） applied to deter- mining appropriate DEM resolutions. The experiment was conducted in three study areas with different terrain conditions, i.e. Xuancheng area with low relief, Coweeta area with high relief, and Kaixian area with more com- plex terrain conditions. The tested topographic attributes were calculated from the DEMs with a series of spatial resolutions （i.e., 5, 10, 15, 20, 25, 30, 50, 100, 150, 200, 300 m）. For each topographic attribute, two wide- ly-used algorithms were tested. One is proposed by Wood （1996）, and the other is the one implemented in Arc- GIS software. The appropriate DEM resolution for a study area had the highest value of the mean of local vari- ance derived from each tested topographic attribute, respectively. Experimental results showed that the effects of slope gradient and curvature are different on the results of the appropriate DEM resolution, while there is little diff

关 键 词：数字高程模型(DEM) 数字地形分析(DTA) 地形信息 适宜分辨率 尺度 

分 类 号：P209[天文地球—测绘科学与技术] P218