عنوان مقاله [English]
Many commonly used spectral image analysis techniques are based on the fact that remotely sensed imagery is sampled with numerous spectral bands at narrow bandwidths (often on the order of tens of nanometers), making it possible to construct a spectrum for each pixel in the image. The spectrum can then be compared with the spectra of known pure materials such as minerals, vegetation, and soil and pixels which are similar to this spectrum can be distinguished. Many of techniques, despite their primary design for use with hyperspectral data, can be applicable logically to multispectral data such as, ASTER. Spectral Angle Mapping (SAM) was performed using spectra extracted from ASTER images to enhance geological phenomena in southwest Ardestan, Isfahan. Pure extraction spectra include the spectrum of green vegetation, illite and calcite. Enhancement of vegetation, clay and carbonate rock units, including shale and lime are the result of the process. The results were compared with geological map, field observations and the accuracy of processing was evaluated.