Classification of Potential Wetlands using the Random Forest in Google Earth Engine in Geomorphological Units - Rio Grande do Sul, Brazil

Abstract

Wetlands are important and valuable ecosystems in the landscape of the extreme south of Brazil. However, they are among the ecosystems threatened by human pressures and climate change. Monitoring and managing these environments is a challenge due to their high spatial and temporal dynamics. The use of remote sensing techniques, supervised classification, and machine learning algorithms offers a promising opportunity to map and monitor wetlands. The objective of this work is to develop a method to map Potential Wetlands (PW) from the integration of images from different satellites, sensor systems, spectral, topographic, climatological and hydrological features, made available on the Google Earth Engine (GEE) cloud user platform. Supervised classification was performed on the geomorphological units Coastal Plain (CP) and Central Depression (CD) considering two classes: Potential Wetlands, which encompasses all types of wetlands, and No Wetlands, for the remaining land use and occupation classes. The supervised pixel-by-pixel classification, individual for each geomorphological unit, allowed more accurate results consistent with previous, consolidated mapping. The PW were mapped with a global accuracy higher than 88% and consumer and producer accuracy higher than 81% in the Coastal Plain and Central Depression. These results allow us to affirm that the proposed methodology enabled the identification of 22% to 24% increase in potential wetlands in geomorphological regions, from spectral signatures, and pixel-by-pixel supervised classification of PW using different image collections and sensor systems.