1. College of History and Tourism Culture, Shanxi Datong University, Datong, Shanxi 037009, China
2. Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
3. College of Architecture and Surveying Engineering, Shanxi Datong University, Datong, Shanxi 037009, China
4. Department of Geomatics, Taiyuan University of Technology, Taiyuan, Shanxi 030024, China