---
title: "Isochrone"
method: GET
path: "/isochrone/json"
tags: ["Routing"]
---

# Isochrone

`GET /isochrone/json`

The NextBillion.ai Isochrone API computes areas that are reachable within a specified amount of time from a location, and returns the reachable regions as contours of polygons or lines that you can display on a map.

## Query parameters

- `key` string, 32 character alphanumeric string, required
- `coordinates` string, latitude,longitude, required
- `contours_minutes` integer, required
- `contours_meters` integer, required
- `mode` 'car' | 'truck'
- `contours_colors` string, value_1,value_2,...
- `polygons` boolean
- `denoise` number
- `generalize` number
- `departure_time` integer

## Response `200`

- object
  - `features` object[] — A [GeoJSON FeatureCollection](https://datatracker.ietf.org/doc/html/rfc7946#section-3.3) object with details of the isochrone contours. Each feature object in this collection represents an isochrone.
    - `properties` object — An object with details of how the isochrone contour can be drawn on a map.
      - `fill` string — The hex code for the fill color of the isochrone contour line.
      - `fillOpacity` number — The fill opacity for the isochrone contour line. It is a float value starting from 0.0 with a max value of 1.0. Higher number indicates a higher fill opacity.
      - `fillColor` string — The hex code for the fill color of the isochrone contour line
      - `color` string — The hex code of the color of the isochrone contour line
      - `contour` number — The value of the metric used in this contour. See the metric property to determine whether this is a time or distance contour. When the metric is time this value denotes the travel time in minutes and when the metric is distance this value denotes the travel distance in kilometers.
      - `opacity` number — The opacity of the isochrone contour line. It is a float value starting from 0.0 with a max value of 1.0. Higher number indicates a higher line opacity
      - `metric` string — The metric that the contour represents - either distance or time
    - `geometry` object — A [GeoJSON geometry](https://datatracker.ietf.org/doc/html/rfc7946#page-7) object with details of the contour line.
      - `coordinates` number[] — An array of coordinate points, in [longitude,latitude] format representing the isochrone contour line.
      - `type` string — Type of the geoJSON geometry.
    - `type` string — Type of the GeoJSON object. Its value is Feature as per the [GeoJSON standard](https://datatracker.ietf.org/doc/html/rfc7946#section-1.4) object.
  - `type` string — Type of the GeoJSON object. As prescribed in [GeoJSON standard](https://datatracker.ietf.org/doc/html/rfc7946#section-1.4), its value is FeatureCollection as the feature property contains a list of geoJSON feature objects.
  - `status` string — A string indicating the state of the response. On normal responses, the value will be Ok. Indicative HTTP error codes are returned for different errors. See the [API Errors Codes](#api-error-codes) section below for more information.
  - `msg` string — Displays the error message in case of a failed request or operation. Please note that this parameter is not returned in the response in case of a successful request.

---

[API](https://skmtc.net/nextbillion-ai/apis/one-spec-service.md) · [All operations](https://skmtc.net/nextbillion-ai/apis/one-spec-service/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/nextbillion-ai/one-spec-service/versions/b647f1808dda/schema)