一种减低DEM数据类型转换对河网提取影响的方法  

A method for reducing the effect of transforming the type of DEM on derived drainage network

作　　者：孔凡哲[1] 宋晓猛[1] 

机构地区：[1]中国矿业大学资源与地球科学学院,江苏徐州221116

出　　处：《中国矿业大学学报》2011年第3期399-404,409,共7页Journal of China University of Mining & Technology

基　　金：国家自然科学基金项目(50309002)

摘　　要：直接将浮点型DEM数据转换为整数型,会改变某些栅格的坡向和坡度,增加DEM中平坦区域和提取的河网中伪河道的数量.为了消除将DEM数据取整对提取河网的影响,提出了首先对DEM栅格高程进行放大,然后再取整的方法.以长台关流域为例,将直接对DEM数据取整和先放大后取整2种情况下提取的河网与由原始DEM提取的河网的对比分析结果为:对104个河段直接取整后只有7个河段的长度是相同的,放大后取整,河段长不相同的只有30个;直接取整后只有27个河段的比降是相同的,放大后取整河段比降不相同的只有16个.采用提出的方法可以得到与原始DEM更加吻合的数字河网.The direction of flow and slope of some digital elevation model（DEM） grids are changed by direct transformation of DEM from float type to integer type,so that the number of plat areas and false reaches derived from DEM are increased.To avoid these problems a new approach was developed,which requires that the float DEM must be magnified first before being transformed to integer DEM.The proposed approach has been tested on the Changtaiguan watershed.A comparison between the drainage structures derived from integer DEM transformed from magnified float DEM and that from the original float DEM was completed.The results show that in 104 reaches,only 7 lengths and 27 slopes of reaches derived from integer DEM are equal to those derived from original DEM,but only 30 lengths and 16 slopes of reaches derived from magnified integer DEM are not equal to those derived from original DEM.It is seen that the proposed approach can produce more realistic digital drainage network.

关 键 词：DEM 整数型 浮点型 数字河网 

分 类 号：P343.1[天文地球—水文科学]