Model based change detection of water body using landsat imagery: A case study of Rajshahi Bangladesh

Abstract

This study detected water bodies which included ponds, lakes, rivers, canals, irrigation land, etc. from Landsat TM (Thematic Mapper) and OLI (Operational Land Imager) data by Pixel Based Model (PBM) for the years 2000 to 2018 and identified the change in area of water body. Rajshahi Division of Bangladesh was selected as the study area for this case study. Landsat 5 data acquired in December 18th, 2000, January 12th, 2001, November 14th, 2005, January 26th, 2006, December 23rd, 2010, and December 14th, 2010 along with Landsat 8 data acquired in December 28th, 2015, January 6th, 2016, December 29th, 2018, and November 18th, 2018 were used as satellite imagery for this analysis. Two images of each month were taken to cover study area. The lowest and highest pixel value of the water body for each band was investigated. Then, a Pixel Based Model (PBM) was formed by using the entire Landsat band and run. The output of the model was shown as a binary image which includes water bodies and non-water bodies. The goal of this study is to verify the accuracy in finding common areas, accreted areas and abolished areas of the water bodies using the PBM model. The results show that overall accuracy of the model is 97% for the year 2000 with Kappa 0.94, 97% for the year 2005 with Kappa 0.94, 99% for the year 2010 with Kappa 0.98, 95% for the year 2015 and 2018 with Kappa 0.90. Also, it was observed that there have been significant changes in the water bodies during the chosen time periods.