1. The Center for Modern Chinese City Studies & School of Urban and Regional Science East China Normal University 500 Dongchuan Road, Minhang District 200241 Shanghai China
2. Department of Geography Ghent University Krijgslaan 281 S8, 9000 Ghent Belgium
3. State Key Laboratory of Resources and Environmental Information System, Institute of Geographic Sciences & Natural Resources Research Chinese Academy of Sciences 11A Datun Road 100101 Beijing China