[1] China Univ Geosci, Sch Land Sci & Technol, Beijing 100083, Peoples R China
[2] China Univ Min & Technol, Jiangsu Key Lab Resources & Environm Informat Engn, Xuzhou 221116, Peoples R China
[3] Beijing Inst Surveying & Mapping, Beijing 100038, Peoples R China
[4] Jiangsu Prov Hydraul Res Inst, Nanjing 210017, Peoples R China