1. School of Civil Engineering and Geomatics, Shandong University of Technology, Zibo 255000, China
2. State Key Laboratory of Resources and Environmental Information System, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
3. College of Urban and Environmental Sciences, Central China Normal University, Wuhan 430079, China
4. College of Geodesy and Geomatics, Shandong University of Science and Technology, Qingdao 266510, China