1. School of Computer Science and Engineering, Xi’an University of Technology, Xi’an, China
2. Northwest Land and Resource Research Center, Shaanxi Normal University, Xi’an, China
3. Faculty of Electrical and Computer Engineering, University of Iceland, Reykjavik, Iceland
4. School of Electronic Information and Artificial Intelligence, Shaanxi University of Science and Technology, Xi’an, China
5. Department of Geography and Spatial Information Techniques, Ningbo University, Ningbo, China