Mostra la percentuale di tempo in cui, tra il 1984 e il 2021, è stata rilevata acqua superficiale in ciascun punto. Il layer deriva dal dataset JRC Global Surface Water (Pekel et al. 2016) distribuito su Google Earth Engine con risoluzione nativa di 30 m. I valori vanno da 0% (acqua rilevata raramente o mai) a 100% (acqua permanente): valori alti indicano corpi idrici stabili, valori intermedi acqua stagionale o intermittente.
This layer quantifies how frequently surface water was present at each pixel across nearly four decades of satellite observation. It reads the occurrence band of the JRC Global Surface Water image, a single pre-computed layer built from the full Landsat archive (1984-2021), where each pixel stores the fraction of valid observations in which water was detected, expressed as a continuous value from 0 to 100%.
| Code | Provider | Resolution | Year |
|---|---|---|---|
| JRC/GSW1_4/GlobalSurfaceWater | JRC (EC) via Google Earth Engine | 30 m | 1984-2021 |
The occurrence band is loaded from Google Earth Engine, clipped to the area of interest and downloaded as a raster; pixels are then rendered on a continuous yellow-to-blue gradient (0% = no/rare water, 100% = permanent water). For each area, the layer reports the minimum, maximum and mean occurrence over valid pixels.