Mapping urban green spaces using an analysis of vegetation indices

The research focuses on the use of advanced remote sensing techniques to combat the effects of climate change in urban areas, with particular reference to heat islands. The proposed methodology, applied to the metropolitan city of Naples, is based on the analysis of very high-resolution satellite images from the WorldView-3 constellation, combining panchromatic and multispectral data through pan-sharpening to obtain detailed maps of urban vegetation, including smaller green spaces such as flower beds, tree-lined avenues, private gardens, green roofs, which are often overlooked because they are difficult to map in a sustainable and widespread manner. Through the calculation of spectral indices (NDVI, MSAVI2, GNDVI, NDRE), the study has enabled not only the precise geolocation of photosynthetically active areas, but also the monitoring of their health status by comparing satellite datasets acquired in June and September 2023. The results highlight marked water stress during the summer period, manifested by a reduction in the average values of the indices. These results constitute a valuable decision-making tool for resilient urban planning and the implementation of Nature-based Solutions, and demonstrate the sustainability and replicability of the methodology in other territorial contexts.