1. Cyberspace Institute of Advanced Technology, Guangzhou University, Guangzhou, China
2. School of Information Science and Technology, ShanghaiTech University, Shanghai, China
3. State Key Laboratory of Remote Sensing Information Engineering for Surveying and Mapping, Wuhan University, Wuhan, China
4. Information Systems Technology and Design Pillar, Singapore University of Technology and Design, Singapore, Singapore
5. Department of Computer Science and Technology, Harbin Institute of Technology, Shenzhen, China
6. Department of Visualization, Texas A and M University, College Station, TX, USA