Approximately one million refugees of the Rohingya minority population in Myanmar crossed the border to Bangladesh on 25 August 2017, seeking shelter from systematic oppression and persecution.This led to a dramatic expansion Astragalus of the Kutupalong refugee camp within a couple of months and a decrease of vegetation in the surrounding forests.As many humanitarian organizations demand frameworks for camp monitoring and environmental impact analysis, this study suggests a workflow based on spaceborne radar imagery to measure the expansion of settlements and the decrease of forests.
Eleven image pairs of Sentinel-1 and ALOS-2, as well as a digital elevation model, were used for a supervised land cover classification.These were trained on automatically-derived reference areas retrieved from multispectral images to reduce required user input and increase transferability.Results show an overall decrease of vegetation of 1500 hectares, of which 20% were used to expand the camp and 80% were deforested, which matches findings from other studies of this Collections case.
The time-series analysis reduced the impact of seasonal variations on the results, and accuracies between 88% and 95% were achieved.The most important input variables for the classification were vegetation indices based on synthetic aperture radar (SAR) backscatter intensity, but topographic parameters also played a role.