1. School of Civil Engineering, Lanzhou University of Technology, Lanzhou 730050, China
2. Emergency Mapping Engineering Research Center of Gansu, Lanzhou 730050, China
3. Cryosphere Research Station on the Qinghai-Tibet Plateau, State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730070, China
4. University of Chinese Academy of Sciences, Beijing 100049, China