Materials and methods
Satellite data: ASTER images
The analysis of digital data was based on the combination of remote sensing and GIS (Geographical Information Systems) using ESRI Arc GIS 10 and ENVI 5.1 as primary tools. Remote sensing data were interpreted using ASTER satellite images. The ASTER instrument is based on the NASA Terra satellite, which is part of the Earth Observing System. It provides high-resolution images of various bands from visible to infrared wavelength in different resolutions (Table 1). The swath width of each scene averages 60 km × 60 km. ASTER data analyzed in this work were obtained from the Earth Remote Sensing Data Analysis Center (ERSDAC) Tokyo, Japan at the 1B processing level. The radiometric and geometric coefficients are corrected. A total of sixteen ASTER images acquired in 2006, 2007 and 2008 (with 0% cloud cover) were used with their spectral and spatial resolutions of the visible Near Infrared and Short wave Infrared bands shown in Table 1.