REMOTE SENSING TECHNIQUES IN UPDATE GEOLOGIC AND GEOMORPHOLOGIC MAPPING OF SEIF AL UWAYNAT, SOUTHEASTERN LIBYA

Abstract

Ten colors composite images of Seif Al Uwaynat were obtained by the superimposition of the data of three Landsat Enhanced Thematic Mapper (ETM) bands. After dynamic enhancement processing (Histogram Gaussian Contrast Stretching) facilitate interpretation of the Seif sand dunes and barchans sand dunes information contained in the original Landsat (ETM 7, 4, 2) data. New information is obtained from these ten colors composite images when it is compared with small scale geological data such as the geological map of Seif AL Uwaynat region. The Landsat ETM of this region reveals a textural, moisture content, patterns and color differentiation with the Quaternary deposits which consist of the Seif (longitudinal) sand dunes and clay deposits along their troughs. This differentiation and the results were not observed or mentioned on the geological map of IRC (2007) and Hunting (1974). Another technique has been accomplished to identify terrain features of Seif AL Uwaynat region using band rationing technique. Terrain features of the study area have been identified by this technique from reflectance bands of Landsat ETM image. Twelve band ratios have been created and each ratio has revealed the terrain features. Single color-composite combinations of three ratios have separated subtle differences between different terrain features uniquely. This study has been on the basis of visual interpretation.