School of Resources and Environmental Science Wuhan University Wuhan 430079 China;
Key Laboratories of Geographic Information Systems Ministry of Education Wuhan University Wuhan 430079 China;
Collaborative Innovation Center for Geospatial Information Science Wuhan University Wuhan 430079 China;
Institute of Geographic Sciences and Natural Resources Research CAS Beijing 100101 China;
China Land Survey and Planning Institute Beijing 100035 China;