Sun at any addressWhich room gets the sun?The buildings round it, and their shadows, at any hour of the year.

The buildings

Every building within a few hundred metres, from Overture Maps' buildings archive (itself built on OpenStreetMap, with outlines traced from imagery where no one has mapped them), read through Sol's own tile server — the same tiles the app's Shadow tab stands its neighbourhood on. A building stands at its surveyed height when the map has one, then at 3.2 m a floor, then at what its kind usually stands: a house 5.5 m, flats 12 m, an office 10 m. A building mapped in parts stands as its parts, so a tower rises from its podium.

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The sun on a spot

The day is sampled every ten minutes from local midnight. A sample counts when the sun stands more than about a degree above the land, when it is in front of the surface — a wall facing away from it is in its own shade — and when the line from the spot toward the sun passes no building. A spot on the ground is read at head height, 1.5 m. The minutes are the app's own rule; the line is tested against each building exactly rather than in steps.

What it leaves out

Trees, hills, awnings, balconies and anything not mapped as a building. Buildings past the edge of the board are not counted, so a spot near its rim can read more sun than it gets. Clear sky is assumed: this is the geometry of the light, not the weather. It is not a measure of brightness or warmth.