Method Study on SRTM Void Data Recovery Based on ArcGIS
Xu Liang1,Peng GuangXiong2,4,Shen Wei3(1.School of Geoscience and Environmental Engineering,Central South University,Changsha 410083,China;2.The Key Laboratory of Shanghai Education Commission for Oceanic Fisheries Resources Exploitation,Shanghai Ocean University,Shanghai 201306,China;3.Key Laboratory of Metallogenic Prediction of Nonferrous Metals,Ministry of Education,Changsha 410083,China)
The digital elevation data of Shuttle Radar Topography Mission(SRTM)is an important foundation data for geospatial modeling.However the void data of SRTM caused by the deficiencies of radar produce great inconvenience for its application.An approach and process flow of SRTM void data recovery is constructed using raster to vector conversion and mask processing technology based on spatial interpolation in ArcGIS software.To ensure the validity of interpolation results,the most important step of this process flow is deleting points of void data.The interpolation accuracy and operations efficiency of Inverse Distance to a Power(IDW),Kriging,Nearest Neighbor(NN)and Spline are compared and analyzed based on a variety of test samples under different conditions.16 test samples of 4×4 pixel window size distribute on different landforms regions,while 12 test samples of different pixel window size from 1×1 to 12×12 locate on the same landforms region.The hollows of SRTM void data are simulated artificially through fill some negative value to the SRTM data in the areas of test samples.With this way to obtain the true value used to estimate interpolation accuracy.The mean of interpolation error is in decreasing order is IDW,NN,Krging and Spline,whose value is 1.32%,1.13%,1.07% and 0.90% respectively.Their standard deviation value are 0.90%、0.81%、0.62% and 75% respectively.Results show that Spline interpolation method is the optimal one applicable to recover void data of SRTM.When the artificial simulation window size of empty area is 4×4 pixels,the mean and standard deviation of interpolation error is 0.90% and 0.75% respectively.With the levels of undulating topography increase,the mean and standard deviation of interpolation error will increase accordingly.On the other hand,interpolation accuracy will descend with the accretion of window size.When the window size of empty area increase form 4×4 pixels to 12×12 pixels,the mean of interpolation error increased from 0.92% to 3.84%,standard deviation increased from 0.75 % to 3.26%.6 × 6 pixels is the largest window size of empty area which can restrict the interpolation error within the data precision of SRTM.Experimental results show that the approach proposed in this paper is a good way to recover SRTM void data only using ArcGIS software.
【Fund】： 中国博士后科学基金(20080430586);; 大洋生物资源开发与利用重点实验室开放基金(B-8208-07-0001-1)
【CateGory Index】： P208
【CateGory Index】： P208