Lineaments of Kodaikanal-Palani massif, Southern Granulitic Terrain of Tamil Nadu, India: a study using SRTM DEM and LANDSAT satellite’s OLI sensor’s FCC

In the present study an attempt has been made to study the lineaments of the Kodaikanal–Palani massif of Tamil Nadu in southern India. Lineaments extracted from eight different azimuth angles of the SRTM DEM, and Landsat-8 satellite’s OLI sensor’s FCC were integrated to generate a lineament data base for the study area. The extracted lineaments were analysed using ArcGIS and Rockworks software to obtain information regarding the number, length, predominant orientations of lineaments extracted individually from both data, and the final output. These apart spatial variation in lineament density has also been analyzed. Estimations from the final lineament output shows that, 2167 lineaments with their total length being 2997.63 km. Areas of high lineament density are found in the western and north western parts of Kodaikanal Taluk. NE–SW directions are predominant orient direction followed by those orienting in N–S and NW–SE directions, and these orientations are in agreement with the trends of the regional geological structures. Distinct variations in the estimations made of the lineaments extracted from SRTM and OLI data is found to exist. About 40 and 38% of the lineaments of the study area are discernible only in the SRTM data and OLI data, respectively and are not found in each other; only 22% of the lineaments of the study area are found commonly in both the data. Furthermore, NW–SE orienting lineaments are more discernible in SRTM data whereas N–S orienting lineaments are more discernible in OLI data. These variations underlines the fact that lineament mapping using any single data source as has been widely followed will not be adequate to give a reliable picture about the lineaments of an area, and further the study stresses the need to extract lineaments from varied satellite images and integrate them to get a reliable picture of the lineaments.