1. Faculty of Geoscience and Earth Observation (ITC), University of Twente, AE Enschede, The Netherlands
2. Department of Geography, University of Zurich, Zurich, Switzerland
3. Key Laboratory of Virtual Geographic Environment (Ministry of Education of PRC), Nanjing Normal University, Nanjing, People’s Republic of China
4. Faculty of Engineering and IT, University of Technology Sydney, Ultimo, Australia