1. College of Earth Sciences, Chengdu University of Technology, Chengdu, China
2. Key Laboratory of Geoscience Spatial Information Technology of Ministry of Land and Resources, Chengdu University of Technology, Chengdu, China
3. Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, China
4. Departement of Geography and Environmental Resources, Southern Illinois University, Carbondale, IL, USA