Mapping and monitoring of Large-Sfax wetlands (center-east of Tunisia) using radiometric indexes and GIS tools

Abstract

Wetlands are characterized by temporary alterations in their structure and composition, and by multifunctionality. Therefore, identifying the boundaries of these zones is essential for appropriate characterization. In this context, this applied research work focuses on the wetlands of Large Sfax in the eastern center of Tunisia. The adopted methodology is based on a combined approach based on multivariate analysis and multi-dates analysis for the identification and the spatial delimitation of wetlands in the study area. The radiometric indexes of humidity NDWI, vegetation NDVI and brightness IB were calculated for the years 2003 and 2015 by using satellite imagery coming from Landsat ETM+7 and Landsat OLI 8. The classification maps of the calculated indexes enabled the identification and spectral delimitation of the wetlands of the study area. The multi-dates analysis was based on the visual interpretation of the panchromatic aerial photographs and the Google Earth snippets for the update of the results. This allowed the spatial delineation and the monitoring of marine, inland, and artificial wetlands in the study area. The importance of using the combined approach is that it allows a better characterization of wetlands.