ASTER VNIR & SWIR Band Enhancement for Lithological Mapping - A case study of the Azegour Area (Western High Atlas, Morocco)

Abstract

The purpose of this study is to emphasize on the ASTER images effectiveness and capabilities in the field of lithological mapping. An ASTER image (L1b) covering the study area has been used. Visible, near-infrared and short wave infrared reflectance data (9 ASTER bands) have been processed and interpreted.

Preprocessing included geometric correction; crossTalk correction; orthorectification. Then the VNIR and SWIR bands have been normalized using the Flat Field Calibration method. Digital processing focused on image enhancement by applying principal component analysis (PCA) and a minimum noise fraction (MNF) transformation. This was achieved by using ENVI 4.7®.

Results showed that there are dissimilarities with the published geological map. Offset between lithological boundaries and the obtained results, textures and/or contrast detected inside homogeneously mapped layers have been observed. The existing geological map contains relevant lithological information, however these results provide a new layer of information that can be used to upgrade it. Thus the image enhancement of ASTER remote sensing data can be used as a powerful tool for lithological mapping.

Keywords: ASTER, Lithological Mapping, Band enhancement, Western High Atlas,