1. School of Geoscience, China University of Petroleum, Qingdao, China
2. College of Geodesy and Geomatics, Shandong University of Science and Technology, Qingdao, China
3. State Key Laboratory of Resources and Environmental Information Systems, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
4. College of Oceanography and Space Informatics, China University of Petroleum, Qingdao, China