Robert Gilmore Pontius Jr, Clark University, Geography, Worcester, MA, United States, Hossein Shafizadeh-Moghadam, Tarbiat Modares University, Department of GIS and Remote Sensing, Tehran, Iran, Masoud Minaei, Ferdowsi University, Department of Geography, Mashhad, Iran and Yongjiu Feng, Tongji University, College of Surveying and Geo-informatics, Shanghai, China