Performance of Sentinel-1 and 2 imagery in detecting aquaculture waterbodies in Bangladesh
November 1, 2022 - Author: J. SebastianHernandez-Suareza, A. Pouyan Nejadhashemia, Hannah Ferriby, Nathan Moore, Ben Belton, Mohammad Mahfujul Haquee
Hernandez-Suarez, J. S., Nejadhashemi, A. P., Ferriby, H., Moore, N., Belton, B., & Haque, M. M. (2022). Performance of Sentinel-1 and 2 imagery in detecting aquaculture waterbodies in Bangladesh. Environmental Modelling & Software, 157, 105534.
In this study, we evaluated the use of synthetic aperture radar (SAR) and multispectral data to detect aquaculture waterbodies in Southern Bangladesh to quantify fish production on a national scale. For this purpose, we developed an object-based framework comprised of three sequential stages: 1) water detection, 2) feature segmentation, and 3) feature classification. Techniques such as Edge-Otsu for binary thresholding, edge detection with convolution filters, and various supervised and unsupervised machine learning methods were used as part of a workflow. We found that ensemble products combining individual subproducts resulted in higher overall accuracy for water detection (overall detection rate around 60%) and waterbodies classification (overall accuracies up to 79%). Moreover, we showed that SAR data and shape indices played important roles in better-discriminating waterbodies. However, limitations in edge detection outcomes affected the identification of small and isolated aquaculture waterbodies, especially those integrated into rice fields, or in areas with trees.