[1] Henan Polytech Univ, Sch Surveying & Land Informat Engn, Jiaozuo 454003, Henan, Peoples R China
[2] Minist Environm Protect Peoples Republ China, Nanjing Inst Environm Sci, Nanjing 210042, Jiangsu, Peoples R China
[3] Louisiana State Univ, Dept Geog & Anthropol, Baton Rouge, LA 70803 USA
[4] Guizhou Inst Environm Sci Res & Design, Guiyang 550018, Guizhou, Peoples R China