School of Remote Sensing and Information Engineering;
Wuhan University;
Wuhan 430072;
China;
State Key Laboratory of Information Engineering in Surveying;
Mapping and Remote Sensing;
Wuhan University;
Wuhan 430072;
China;
Department of Civil and Environmental Engineering;
Norwegian University of Science and Technology;
Trondheim 7491;
Norway;
urban spatial structure; variable area unit(VAU); spatial metric; social function likelihood; Open-StreetMap;