15-Minute City Isochrone Contour Map (2D)

Place an Amenity

Pick a type, then click any block on the contour map to place it there (click again to remove). The contour lines trace equal walk-time boundaries to the farthest essential amenity type, exactly like a topographic map.

City Parameters

Walking speed 4.8 km/h

Target time — the "N" in N-minute city 15 min

City block size 80 m

Live Readouts

Full coverage

Avg. walk to nearest

— min

Amenities placed

Worst block

— min

Within target — all 4 types reachable

Partial — some types missing/late

Far / type not built yet

How it works

Same walk-time model as the "15-minute city" planning target (Paris, Melbourne, Portland), rendered as a true topographic-style isochrone map instead of a coloured 3D block city — the contour lines below are extracted numerically from the exact same time field with the marching-squares algorithm:

walk time (min) = Manhattan distance along streets (m) / walking speed (m/min)
Manhattan distance = |Δgx| · block + |Δgz| · block   (grid streets, not straight-line)
block time          = max over 4 amenity types of ( time to nearest instance of that type )
"full coverage"      = block time ≤ target time N
contour line at L    = the boundary curve where block time crosses level L (marching squares)

Manhattan (grid) distance is used because real pedestrians walk along a street network, not through buildings — the standard metric in walkability research (e.g. Walk Score isochrones). The dashed/solid contour lines are drawn at N/2, N and 1.5·N minutes, so you can see how much a block would gain or lose from a stricter or looser target without re-reading every cell's colour by eye.

Place amenities — click a block after choosing a type; a block only turns fully green once a school, grocery, park and clinic are all within the target time.
Walking speed — average adult pace is ≈4.8 km/h (80 m/min); slower for children/elderly, faster for a brisk commuter.
Target time N — the "15" in 15-minute city; dragging it re-scores every block and redraws the contour instantly.
Histogram (below the map) — the distribution of walk times across every fully-served block, with the current target line marked — a statistical view the 3D block city never showed directly.