Mapping the coastal geomorphological landforms through Aster DEM and Landsat data – a case study from Tuticorin-Vembar coastal stretch, southeast coast of India

Abstract

The present study highli ghts the importance of digital elevation model and satellite imageries for mapping the coastal geomorphological landforms in Tuticorin-Vembar coastal stretch, southeast coast of India. Aster DEM 30 meter resolution data and Landsat 2006 image (30 meter resolution) of the study area were overlayed together with 30 and 70 percent transparency ratio respectively in ArcGIS platform. Further, a hillshade layer derived from Aster DEM has been included to visualize the surface morphology of the study area. Visual interpretation technique was used for identifying the various coastal geomorphological landforms in the study area. The results were cross validated through a GPS based field check. Based on the analysis, we have found that the study area has a wide variet y of geomorphological landforms such as beach ridges, alluvial plains, deltaic plains, channel deposits, sand dunes, linear ridges, mud flats, plain lands, salt marsh, sand sheets, sand bars, beaches and backwater channels. The dominant landform features l ike the beach ridges and alluvial plains are found near to Vembar and Vaippar river systems. Saltpans are other dominant features, which have been evolved from scrapping the mud flats and salt marsh lands by human induced activities. The concept used in th is paper provides a cost effective and time saving technique for mapping the coastal geomorphological landforms at a resolution of 30 meters. However, micro scale mapping at 1- meter resolution using LIDAR datasets needs to be explored in future.