Population data. EC JRC Global Human Settlement Layer (GHS-POP) 2025 epoch, 100m grid, clipped to the British Isles. 4.46 million populated cells. The GHSL is modelled data — counts at very small radii are estimates, not census counts.
Green spaces. OpenStreetMap polygons tagged as parks, gardens, golf courses, woods, grassland, heath, scrub, beaches, forests, meadows, recreation grounds and village greens (2.2M polygons). “Min green space size” filters these by area in hectares — the tool measures access to green spaces of at least that size.
Blue spaces. OSM water bodies and reservoirs (247k polygons).
Coast. Distance to the nearest coastline (GB coastline extract), reported as the population-weighted average for the circle and the nearest from your point.
Access metrics. For every populated grid cell we precomputed the straight-line (Euclidean) distance in metres to the nearest qualifying green and blue space polygon. “Within 300m” is the widely used benchmark for good access to green space. Circle results aggregate all grid cells whose centre falls within the radius; the population-weighted average distance is reported alongside the share of residents within 300m.
Limitations. Straight-line distance, not route distance. OSM coverage/quality varies by area. Grid cells are 100m; small circles sample few cells.
Inspired by Tom Forth’s circlepopulations tool. Data licences: GHSL (EU open data), OpenStreetMap (ODbL).