1. College of Geomatics and Geoinformation, Guilin University of Technology, Guilin, China
2. Guangxi Guiyu Engineering Consulting Co, LTD, Nanning, China
3. School of Hydraulic Engineering, Guangxi Vocational College of Water Resources and Electrick Power, Nanning, China
4. School of Geodesy and Geomatics, Wuhan University, Wuhan, China