1. School of Geography and Planning, Sun Yat-Sen University, Guangzhou 510006, China
2. Guangdong Provincial Engineering Research Center for Public Security and Disaster, Guangzhou 510275, China
3. Guangdong Key Laboratory for Urbanization and Geo-Simulation, Sun Yat-Sen University, Guangzhou 510275, China
4. The Urban Institute, Heriot-Watt University, Edinburgh EH14 4AS, UK
5. School of Mathematics, University of Birmingham, Birmingham B15 2TT, UK