Geomatica-Based Approach for Automatic Extraction of Lineaments from ASTER-GDEM Data, in Part of Al-Rawdah, Shabwah, Southeast Yemen

Lineaments are considered one of the most important topographic features used in exploring resources such as minerals, groundwater, oil, and gas; besides, they are indicators of structural and tectonic basin. Geomatica-and GIS-based techniques have been used for extracting lineaments in part of Al-Rawdah, Shabwah, southeast Yemen. High-resolution 30-m ASTER GDEM shaded images with different sun angles are used in delineating lineaments in different distinct relief and topography. Various softwares are as follows: Arc GIS has been used for extracting various hill-shaded image and Geomatica (2013) has been used to enhance hill-shaded image and to extract lineaments using various default parameters, whereas RockWork14 has been used to indicate trend of the lineaments. Moreover, Arc GIS 10.2.2 has used for overlying, mapping, visualizing, and calculating different parameters. Eight hill-shaded images have been extracted with different sun angles. Shaded images of sun angles 0 degrees, 45 degrees, 90 degrees, 135 degrees were combined as one image for better enhancements. The next four shaded images, i.e., hill-shaded images of sun angles 180 degrees, 225 degrees, 270 degrees, and 315 degrees, were combined as one hill-shaded image. The two hill-shaded images combined were used for automatic extraction of lineaments and give N-NE and S-SE and N-NW and S-SE directions, respectively; however, they vary in their density. In addition, fault map identified NW-SE direction and was compared with last two combined hill-shaded images; when superimposed with them, it indicates that most of the lineaments are perpendicular to fault line and some match with it properly where the majority of the lineaments occur along hard rocks. The final superimposed image of all lineaments map has been classified into three types of lineaments: micro-, minor, and medium which have total number of 1040, 324 and 8 respectively with the length of 1368, 1050, and 157.5 km, respectively. Rose diagram indicated that the dominant trend of lineaments is NW-SE. The present study demonstrates the utilization of software for automated extraction of lineaments and their relationship with major structural features.