1. School of Surveying and Mapping and Land Information Engineering, Henan Polytechnic University, Jiaozuo 454003, China
2. Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
3. State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
4. University of Chinese Academy of Sciences, Beijing 100049, China
5. Key Laboratory of GIS & RS Application, Xinjiang Uygur Autonomous Region, Urumqi 830011, China