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isochrone

isochrone

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github.com/capanMaps & Travel2Updated 6w ago
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About isochrone

isochrone maps reachable Berlin street networks by travel time and mobility profile, rather than drawing filled polygons. It also ranks areas against weighted everyday destinations.

Key features

  1. 01Street-level reachability by arrival time
  2. 02Walk, stroller, and wheelchair profiles
  3. 03Weighted ranking across seven destination types
  4. 04Precomputed citywide reachability surfaces

Use cases

  1. 01Check streets reachable within a time budget
  2. 02Compare access from different starting points
  3. 03Rank Berlin areas by weighted daily needs

MCP support

The `isochrone-mcp` package exposes a `reachable_area` tool to MCP clients. It accepts an origin, time limit, profile, and optional target, then returns a prose summary and map link.

Configuration

Local server config is the same for every client. Copy it into your client’s MCP config file.

mcp.json · Universal config
{
  "mcpServers": {
    "capan-isochrone": {
      "command": "npx",
      "args": [
        "-y",
        "isochrone-mcp"
      ]
    }
  }
}
Run commandnpx -y isochrone-mcp

Local servers need a runtime on your machine (e.g. Node.js 18+). Config file locations differ by client; see your client’s docs.

Packages
npmisochrone-mcp0.1.4

Tools

2

Saved tool list · updated 2w ago

ParameterTypeRequiredDescription
latnumberYesOrigin latitude (WGS84)
lonnumberYesOrigin longitude (WGS84)
targetobjectNoOptional destination: reports whether it's reachable in the time budget and the approximate arrival time
target.latnumberYes
target.lonnumberYes
minutesintegerNoTime budget in minutes. Faster profiles allow fewer: walking allows up to 25, cycling up to 10, because the work grows with the area searched. Omit to use the profile's sensible default.
profileenumNoMobility profilewalk | stroller | wheelchair | bike
include_placesbooleanNoAlso summarise how many places of each group are reachable (food, shops, culture, health, learning, outdoors, money)
include_geometrybooleanNoAlso return the raw GeoJSON (10 arrival-time bands, large)

Details

From the project README

isochrone

demo uptime

Live: iso.huseyincapan.dev

Click anywhere on the map and see the street network you can actually reach on foot within 15 minutes — coloured by arrival time, with mobility profiles that account for stairs and unpaved paths.

OSM data → PostGIS + pgRouting → Express → Leaflet.

Same corner, same 15 minutes, drawn two ways: the reachable street network against the hull drawn around it

Why not a polygon?

Every isochrone map I could find answers with a filled polygon. That is wrong unless you are a pigeon: a polygon claims you can reach the middle of a block, cross a rail cutting, walk through a building. On the corner above, the same 15 minutes gives you 107.6 km of reachable streets; the hull drawn around them covers 3.28 km² and claims 30.4 km of street the walk cannot actually reach. This map draws the network.

How it works

pgr_drivingDistance walks the street graph from the vertex nearest your click until the time budget runs out, and returns every reachable edge with its arrival time. Those edges are grouped into 10 equal time bands and drawn directly.

Edge cost is length / speed in seconds, computed per request from the selected profile, so a profile is a few numbers rather than a schema change:

profilespeedstairsunpaved
walk1.4 m/shalf speednormal
stroller1.2 m/simpassable0.6×
wheelchair0.9 m/simpassableimpassable

These factors are estimates, not measurements — see Known gaps.

Where should I live?

Answer a short questionnaire weighting seven everyday layers (dining, green space, playgrounds, groceries, health, kindergartens, schools) and the whole Berlin map re-ranks to show where your weighted 15-minute city actually is, as walk, bike or wheelchair.

The trick is that nothing is routed at question time: 21 full-city reachability surfaces (7 layers × 3 profiles, ~134,000 grid cells each) are precomputed offline, so re-ranking the city is one aggregate query. Stroller is deliberately absent here: its speed factors are uncalibrated estimates and must not be published as if measured.

Ask Claude about it (MCP)

The isochrone-mcp package lets any MCP client answer reachability questions against this API:

claude mcp add isochrone -- npx -y isochrone-mcp
Claude answering a reachability question, then the isochrone drawn on the map

One tool, reachable_area: origin + minutes + profile, optional target ("can I get there in time?"). Returns a prose summary and a map link, not coordinate soup. Details in mcp/.

Known gaps

  • Graph islands. The vertex nearest a click can sit on a disconnected fragment — 52.515,13.400 reaches 13 nodes. Fix is a one-time pgr_connectedComponents table for the vertex lookup to join against.
  • Calibration. The speeds above are guesses. Google's Isochrones API (Preview) supports WALK and returns GeoJSON, so the walk profile could be calibrated against it. It has no stroller/wheelchair mode, so those stay unvalidated.
  • Stranded origins render as a tiny blob rather than saying "unreachable with this profile".

Running it yourself

Dev setup, deployment, city import and the ops notes live in docs/OPERATIONS.md.

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