DEM随机噪声误差去除方法研究--以黄土沟沿线地形剖面为例  

Method for Noise Removal of DEMs:A Case Study on Terrain Profile of Loess Shoulder Line

作　　者：曹建军[1,2] 那嘉明 汤国安[1] 杨昕[1] CAO Jian- jun NA Jia-ming TANG Guo-an YANG Xin(School of Geography Science ,Key Laboratory of Virtual Geographic Environment of Ministry of Education ,Nanjing Normal University, Nanjing 210023 School of Environment Science ,Nanjing Xiaozhuang University ,Nanjing 211171 ,China)

机构地区：[1]南京师范大学地理科学学院,虚拟地理环境教育部重点实验室,江苏南京210023 [2]南京晓庄学院环境科学学院,江苏南京211171

出　　处：《地理与地理信息科学》2017年第2期12-18,F0003,共8页Geography and Geo-Information Science

基　　金：国家自然科学基金项目(41671389、41471316、41401441)

摘　　要：在黄土高原数字地形分析中,基于DEM提取的地形参数和地貌对象是研究黄土地形地貌特征的基础。但在使用这些对象和参数进行小流域尺度的数字地形分析时,DEM数据中隐含的噪声在一定程度上会影响分析结果的可靠性。该文以分别位于陕北黄土丘陵沟壑区(绥德)和黄土塬区(淳化)的两个小流域为试验区,以国家基础地理数据库5m分辨率DEM为实验数据,以黄土地貌中最具典型特征的沟沿线为研究对象,对其地形剖面所隐含噪声的特征、提取及去除方法进行了研究。实验中采用EMD-MFDFA和EEMD-MFDFA两种组合方法对上述两个小流域黄土沟沿线地形剖面数据进行了分析。实验结果显示,沟沿线地形剖面数据噪声与地形复杂程度有很大关系;同EMD-MFDFA方法相比,EEMD-MFDFA对去除噪声成分具有更好的效果;EEMD-MFDFA方法在上述两个样区的沟沿线原始剖面与降噪后重构地形剖面的RMSE分别为2.053m和3.188m。Terrain parameters and obiects derived from the DEMs are the basis of geomorphologic studied, especially in loess plateau of China. However, when analyzing in the scale of watershed, the topographic noises of DEMs are often ignored. In this paper, taking Suide and Chunhua as the study areas,and the loess shoulder-lines as research objects, the characteristics, extrac- tion,and removal method of the topographic noises are studied. Firstly, terrain elevation is sampled by loess shoulder-line ex- tracted by DEMs. Then, EMD and EEMD is performed to obtain the components of the sampling data. Finally, the Hurst index （Hq） in MF-DFA is analyzed for the spatial distribution of the topographic noises. The results show that： 1） the noise of the terrain profile along the shoulder-line has a great relationship with the terrain complexity; 2） compared to the EMD-MFDFA method, the EEMD-MFDFA method has a better effect in mitigating the topographic noise of loess shoulder-line; 3） the RMSE between the original terrain and the terrain after noise removal using the EEMD-MFDFA method is 2. 053 m in Suide and 3. 188 m in Chunhua.

关 键 词：DEM 沟沿线 噪声 EEMD MF-DFA 

分 类 号：P931[天文地球—自然地理学]