NSFC-DFG Sino-German Cooperation Group on Urbanization and Locality(UAL);
College of Architecture and Landscape Architecture, Peking University, Beijing 100871, China;
Key Laboratory for Earth Surface Processes, Ministry of Education, Peking University, Beijing 100871, China;
Key Laboratory for Earth Surface Processes, Ministry of Education, Peking University, Beijing 100871, China;
College of Urban and Environmental Sciences, Peking University, Beijing 100871, China;