Shoreline delineation using Google Earth images: A case study for Agoo, La Union, Philippines

Abstract

Actual ground monitoring requires extensive processes, which can be expensive and time-consuming. Images of different places generated by remote sensing can be an alternative source of information for analysis. In this study, we presented a method for detecting and extracting the shoreline using satellite images from Google Earth. We utilized a computer algorithm to perform the image processing tasks such as threshold segmentation, edge detection, and automatic curve selection. These procedures are necessary for distinguishing the land area from the ocean portion of the image. Also, it allows us to detect the shoreline position, which can be used to calculate the accretion and erosion in the study area. We applied this method in Agoo, La Union wherein a groin field is implemented as their coastal protective structure. The shoreline positions from 2016 to 2022 are obtained through the collected satellite images. Extracted data points from each year are plotted, and a visualization of the shoreline change within the vicinity of the groin field is presented. It is observed that the constructed groin field alters the shape of the shoreline as compared to its previous form. Based on the results, we identified that the proposed method is applicable for shoreline detection and extraction.