1. School of Information Engineering, China University of Geosciences, Beijing 100083, China; State Key Laboratory of Resources and Environmental Information System, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing100101, China
2. School of Information Engineering, China University of Geosciences, Beijing100083, China
3. State Key Laboratory of Resources and Environmental Information System, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing100101, China
4. Research Institute of Surveying and Mapping Standardization, Ministry of Natural Resources,Xi’an710054, China