Spectral Angle Mapper Approach (SAM) for Land Degradation Mapping: A Case Study of the Oued Lahdar Watershed in the Pre-Rif Region (Morocco)

Land degradation is a complex and widespread environmental issue with significant implications for global sustainability. It encompasses various processes that negatively impact soil health and support productive ecosystems and human livelihoods. This chapter focused on mapping land use/land cover (LULC) and identifying land degradation features using Sentinel-2 imagery and the Spectral Angle Mapper (SAM) approach. The primary objective was to gain insight into the spatial distribution of land degradation within the study area. The step-by-step supervised classification process involved data preparation, training data collection, feature selection, SAM classification, and post-classification processing. An accuracy assessment was conducted to validate the results and ensure the reliability of the land cover map. As a result of the different LULC classifications in the research area, the arboriculture class represented 18% of the study area. In contrast, the agriculture class showed coverage of 27%, followed by the forest class occupying 22% of the catchment area, and the bare soil class representing 33% of the total study area. The combination of substantial proportions of bare soil (33%) and agriculture (27%) suggested that a large portion of the landscape may be susceptible to land degradation if appropriate measures are not implemented. The derived LULC map is a valuable resource for environmental monitoring, ecosystem conservation, and land use planning. Policymakers, researchers, and stakeholders can use this information to make informed decisions for sustainable land management, protect natural resources, and mitigate the impact of land degradation.