1. School of Geography, South China Normal University, Guangzhou 510631, China
2. Guangdong Shida Weizhi Information Technology Co., Ltd., Qingyuan 511500, China
3. SCNU Qingyuan Institute of Science and Technology Innovation, Qingyuan 511500, China
4. College of Civil and Transportation Engineering, Shenzhen University, Shenzhen 518060, China