Voronoi cells over London zones 1–2: the nearest station vs the nearest place name on the map.
place nodes (Voronoi approximation),
ONS electoral ward boundaries (Dec 2024, OGL), and Church of England parish boundaries —
the traditional parishes that named much of London. "Delta" colours each point by whether
the nearest station's name fuzzily matches the place name there; grey = no boundary data.
Map © OpenStreetMap contributors.