RS and GIS for mapping of coastal landforms

Paper Review Report

Background and Goal of Study

The Coast landform are undergoing various changes due to various factors like environmental change i.e. Global warning and Construction on the Coastal water. These changes need to quantified, what may be the reason, which will be helpful for the Coastal water & land Management Departments for predicting the various changes in the geography. These can only be Quantified (database creation) if some technique and software is use.

The primary aim of the present study is to map coastal landforms and assess the volumetric change of sediment load over a decade along the south-west coast of Kanyakumari using integrated remote sensing and GIS techniques. The present study therefore used different change detection techniques such as (i) topographical change analysis, (ii) cross-shore profile change analysis, (iii) DEM of Difference (DoD) algorithm based Geomorphic Change Detection (GCD) analysis for estimating the volumetric changes (land loss or land gain) along the coastal stretch using the ArcGIS platform.

Methodology

Mapping of coastal landforms:

The GIS and integrated Remote Sensing has been used for creating the coastal geomorphological landforms at high resolution. The various spatial source used as input i.e. topographical map (scale 1:25,000), Landsat ETM+ image & IKONOS multi-spectral images. Then ASTER and SRTM DEM datasets are used in Arc GIS to make Map. The Garmin ETREX 30 GPS are use for ground truth verification, pre and post field verification.

DEM of Differencing of volumetric change analysis:

The GIS-based Geomorphic Change Detection (GCD) analysis provides volumetric change of sediment load in the landforms using DEM datasets acquired over periods of interval. The GCD method use the Difference of Digital Evaluation Model (DEM) of two different time using algorithm to estimate the quantitative changes of landforms of the earth surface, in a diverse set of environments, and at a range of spatial scales and temporal frequencies. In this research Geomorphic Change Detection of coastal landforms is estimated from SRTM and ASTER DEM datasets acquired for the years 2000 and 2011 respectively using DEM of Difference (DoD) method. The DoD is a mathematical algorithm for quantifying the volumetric change of the landforms using DEM datasets acquired on two different periods.

The DoD algorithm computes the differences by subtracting pixel values of two DEMs using the equation δE = Z₂ -Z₁, where δE is a output DEM showing changes in volumetric scale (m3 ); Z₁ is a DEM of earlier period (i.e. SRTM DEM acquired on February 2000, and Z₂ is a DEM of later period (i.e. ASTER DEM acquired on October 2011). Thus, the output DEM provides volumetric change of sediment load (δE) on various landforms due to erosion and deposition with time. In which, the negative and positive values represent the land lost (erosion) and land gain (deposition)

Finally, the output map is converted into vector layer for preparation of geo-database of landform features with attributes including name, areal extent, and volumetric change rate using ESRI-ArcGIS 10.2 software.

Conclusions

This research paper Demonstrated the use of GIS and integrated remote Sensing for Mapping of coastal landforms and Volumetric change analysis.

The DoD analysis of geomorphic change assessment reveals changes in morphologies due to erosion or deposition processes. The spatial variation of sediment load suggests morphologies of the landforms are closely related to the marine and terrestrial processes.

Reference
Mapping of coastal landforms and volumetric change analysis in the south west coast of Kanyakumari, South India using remote sensing and GIS techniques. S. Kaliraj et al. / The Egyptian Journal of Remote Sensing and Space Sciences 20 (2017) 265–282.

Review by,

Kamran ullah Khan