查看文章

The Landsat archive presents a unique source for mapping and monitoring of shrublands. Still, efficient and accurate mapping approaches are needed that provide shrub cover fraction estimates over space and time. The spectral signal of shrubs is composed of green vegetation and non-photosynthetic vegetation as well as varying fractions of soil, grass, and shadow, which makes a direct mapping of fraction cover challenging. In this study, we mapped 32 years of shrub cover fractions from annual Landsat best observation composites covering a rockrose (genus Cistus) ecosystem in the Baixo Alentejo region of southern Portugal. Fraction mapping was based on a multi-year support vector regression model trained with synthetically mixed data from a multi-annual image spectral library. Resulting fractions maps were validated using reference information derived from high-resolution satellite imagery available for …