Harp Piemonte — Multitemporal mosaic NDVI from Sentinel images (2017-2018)

The dataset is a mosaic, created by Arpa Piemonte, of images in false colours obtained as original data processing of the Sentinel 2A satellite (European Copernicus programme). The images are appropriately mosaiced to cover the Piedmontese, Ligurian and Valdostan territory according to a series of 12 tiles. Each image is a composition of three seasonal vegetation indices (NDVI) superimposed in the three channels of the RGB monitor: spring 2018, summer 2018 and autumn 2017.NDVI is an index based on the reflectance measures acquired in the spectral regions of red and near-infrared and is strongly related to the chlorophyll content and, if measured over time, to the phenological cycle of plants. The overlapping of the seasonal NDVI allows to differentiate the areas for which there are one or more vegetative cycles or in any case variations of the soil cover (areas variedly colored) from those where the soil is completely devoid of vegetation or with permanent water (gray to black shade). The elaboration was carried out by Arpa Piemonte as part of the activities related to the national project of Monitoring of Soil Consumption 2018 conducted by the National System for Environmental Protection (SNPA) through the coordination of ISPRA and the involvement of several regional agencies. The project aims to monitor the transformations of the territory due to urban, infrastructural, commercial expansions, etc. with the consequent loss of natural, agricultural and semi-natural soil, understood as an essential and fundamentally non-renewable environmental resource. The methodology of analysis uses, for the first time on a national scale in a uniform and uniform way, the new Sentinel 2A/B images which, given their level of detail and the frequency of revisitation guaranteed by the Sentinel mission, allow to obtain overviews of the national territory in a regular and constant way (multi-time analysis).The comparison between these allows to highlight the main transformations of the territory and the related phenomena of land use (expansion of urban settlements, new roads, shipbuilding for new works, etc.).