Utilization of LiDAR DTM for Systematic Improvement in Mapping and Classification of Coastal Micro-Geomorphology

Abstract

The dynamicity of the coastal landforms necessitates monitoring from space-borne or aerial remote sensing platforms. Precise elevation information is an important requirement to delineate the subtle topographic variations along and across the coastal axes, indicative of coastal geomorphology at large scale. The study was carried out for a coastal stretch of 25 km, located between Visakhapatnam and Kakinada districts of Andhra Pradesh state, where the depositional activity is dominated. In the present study, we aim to demonstrate the utility of high resolution digital terrain model derived from the advanced Light Detection and Ranging (LiDAR) technology, in identification and delineation of the micro-geomorphic units along this coastline. The four level classifications of the landforms were also proposed based on genesis of landforms, geological sub-provinces, landform shape and morphological attributes as level 1, 2, 3 and 4, respectively. The higher-order landforms of level 4, such as beach berms, beach ridge crest, dune crest and toe, interdunal depression, etc. are delineated using the cross-shore elevation profile, slope and signed curvature information derived from LiDAR DTM with the subtle contrasts of elevation (1–2 m). The beach ridge–swale complex, dune and beach berms were chosen as the key depositional elements to define the morphological attributes in terms of shape and curvature values. This has enabled creation of micro-geomorphology map at 1:5000 scales over the study area as well as classification of the landforms into 4 levels, thus providing significant input for coastal resource mapping and management.