Comparing the Capability of Sentinel-2 and Landsat 9 Imagery for Mapping Water and Sandbars in the River Bed of the Lower Tagus River (Portugal)

Mapping river beds to identify water and sandbars is a crucial task for understanding the morphology hydrodynamics of rivers their ecological conditions. The main difficulties this so far have been limitations conventional approaches, which are generally costly (e.g., equipment, time- human resource-demanding) poor flexibility deal with all Currently, alternative approaches rely on remote sensing techniques, offer innovative tools mapping bodies in quick cost-effective manner based relevant spectral indices. This study aimed compare capability using imagery from Sentinel-2 newly launched Landsat 9 satellite achieve goal. For segment Lower Tagus River (Portugal) conditions very low discharge, comparison Normalized Difference Water Index, Modified Augmented Automated Extraction Index calculated two satellites shows that satellites’ datasets were consistent therefore could be used complementarily. However, results highlighted need classify index-specific classification decision values, an important factor quality information extracted.