WANG De-sheng^{1, 2, 3}, LIU Jun-zhi^{1, 2, 3}, ZHU A-xing^{1, 2, 3, 4, 5}, WANG Shu^{1, 2, 3}, ZENG Can-ying^{1, 2, 3}, MA Tian-wu^{1, 2, 3}

¹ Key Laboratory of Virtual Geographic Environment, Nanjing Normal University, Nanjing 210023, P.R.China
² State Key Laboratory Cultivation Base of Geographical Environment Evolution (Jiangsu Province), Nanjing 210023, P.R.China
³ Jiangsu Center for Collaborative Innovation in Geographic Information Resource Development and Application, Nanjing 210023, P.R.China
⁴ State Key Laboratory of Resources and Environmental Information System, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, P.R.China
⁵ Department of Geography, University of Wisconsin-Madison, Madison, WI 53706, USA