Built-Up Area

Fractional (0-1) or binary coverage of built-up surface per pixel, capturing the spatial extent and morphology of human settlements. Flagship products: GHSL BUILT (Copernicus, multi-epoch back to 1975, 10 m / 100 m), WSF 2019 (DLR World Settlement Footprint, 10 m binary), and the "Built-up" class (code 50) in ESA WorldCover 10 m. Distinct from `impervious-surface` (which measures physical impermeability — some built-up classes such as sparse rural housing are not fully impervious) and from `population` (which counts inhabitants). Urban Areas is a candidate but not-yet-adopted GCOS ECV in the 2022 Implementation Plan, so this concept ships parentless in the operational tier and migrates to the framework tier if/when GCOS ratifies the variable.