Automatic shoreline extraction and change detection: A study on the southeast coast of Bangladesh

Abstract

One of the multifaceted features of the Earth's surface is the shoreline, which is always changing and has enhanced economic and environmental values. This paper highlights the shoreline of Bangladesh's southeast coast from 1980 to 2020 with a 10-year interval to automatically extract the shoreline and the changes in coastline position due to accretion and erosion. Threshold, Sobel, Prewitt, Canny and Robert generic edge detection algorithms are used for automatic shoreline extraction, including canny's performance in accurately detecting the coastline. The Digital Shoreline Analysis System (DSAS) is carried out using Net Shoreline Movement (NSM), End Point Rate (EPR), and Linear Regression Rate (LRR) to statistically measure shoreline changes. The findings suggest that in terms of accretion and erosion, the shoreline is dynamic, but overall accretion is dominated rather than erosion. Because of both natural processes and anthropogenic interventions, the coastline in this area has changed increasingly. The result shows that maximum erosions reached between 2010 and 2020 are 2673.64 m for NSM and 284.49 m/yr for EPR, whereas the maximum accretions are 4689.4 m for NSM and 469.58 m/yr for EPR between 1980 and 1990. LRR tracks coastline variation over a 40-year period in which 162.91 m/yr and 45.91 m/yr, respectively, are the highest accretion and erosion observed. It is anticipated that the outcome of this study will help to understand the possible risks of future changes in the coastline that will require the country to establish planning and management strategies for its very significant southeast shoreline.