1. Department of Geography, Ghent University, Ghent, Belgium
2. Department of Geospatial Information Engineering, Information Engineering University, Zhengzhou, China
3. Faculty of Geographical Science, Beijing Normal University, Beijing, China
4. Department of Geodesy and Geoinformation, Research Group Cartography, TU Wien, Vienna, Austria
5. Institute of Geography, Augsburg University, Augsburg, Germany
6. Chair of Cartography and Visual Analytics, Technical University of Munich, Munich, Germany