1. School of Resource and Environmental Sciences, Wuhan University, Wuhan, China
2. Department of Geography, University of California, Santa Barbara, California, USA
3. Key Laboratory of Geographic Information System, Ministry of Education, Wuhan University, Wuhan, China
4. Key Laboratory of Digital Mapping and Land Information Application Engineering, Ministry of Natural Resources, Wuhan University, Wuhan, China
5. School of Civil Engineering, Tianjin University, Tianjin, China