## Calculate an isochrone from a point

`RoutingIsochronePostResponse Routing.IsochronePost(RoutingIsochronePostParamsparameters, CancellationTokencancellationToken = default)`

**post** `/api/v1/isochrone`

Calculate an isochrone from a point

### Parameters

- `RoutingIsochronePostParams parameters`

  - `required Double lat`

    Latitude

  - `required Double lng`

    Longitude

  - `required Double time`

    Travel time in seconds (1-7200)

  - `string format`

    Response format: json (default), geojson, csv, ndjson

  - `string mode`

    Travel mode (auto, foot, bicycle)

  - `string outputFields`

    Comma-separated property fields to include

  - `Boolean outputGeometry`

    Include geometry (default true)

  - `string outputInclude`

    Extra computed fields: bbox, center

  - `Long outputPrecision`

    Coordinate decimal precision (1-15, default 7)

  - `Double outputSimplify`

    Simplify geometry tolerance in meters

### Returns

- `class RoutingIsochronePostResponse:`

  GeoJSON Feature or FeatureCollection representing isochrone polygons — areas reachable within the specified travel time(s). Single time value returns a Feature; comma-separated times return a FeatureCollection with one polygon per contour.

  - `IReadOnlyList<GeoJsonFeature>? Features`

    Array of isochrone polygon Features (multi-contour only)

    - `required GeoJsonGeometry Geometry`

      GeoJSON Geometry object per RFC 7946. Coordinates use [longitude, latitude] order. 3D coordinates [lng, lat, elevation] are used for elevation endpoints.

      - `required Coordinates Coordinates`

        Coordinates array. Nesting depth varies by geometry type: Point = [lng, lat], LineString = [[lng, lat], ...], Polygon = [[[lng, lat], ...], ...], etc.

        - `IReadOnlyList<Double>`

        - `IReadOnlyList<IReadOnlyList<Double>>`

        - `IReadOnlyList<IReadOnlyList<IReadOnlyList<Double>>>`

        - `IReadOnlyList<IReadOnlyList<IReadOnlyList<IReadOnlyList<Double>>>>`

      - `required Type Type`

        Geometry type

        - `"Point"Point`

        - `"LineString"LineString`

        - `"Polygon"Polygon`

        - `"MultiPoint"MultiPoint`

        - `"MultiLineString"MultiLineString`

        - `"MultiPolygon"MultiPolygon`

    - `required IReadOnlyDictionary<string, JsonElement> Properties`

      OSM tags flattened as key-value pairs, plus `@type` (node/way/relation) and `@id` (OSM ID) metadata fields. May include `distance_m` for proximity queries.

    - `required Type Type`

      Always `Feature`

      - `"Feature"Feature`

    - `string ID`

      Compound identifier in `type/osm_id` format

  - `GeoJsonGeometry? Geometry`

    GeoJSON Geometry object per RFC 7946. Coordinates use [longitude, latitude] order. 3D coordinates [lng, lat, elevation] are used for elevation endpoints.

  - `Properties? Properties`

    Isochrone metadata

    - `Double? AreaM2`

      Area of the isochrone polygon in square meters (multi-contour features only)

    - `Double? MaxCostS`

      Maximum actual travel cost in seconds to the isochrone boundary (single contour only)

    - `Mode Mode`

      Travel mode used for the isochrone calculation

      - `"auto"Auto`

      - `"foot"Foot`

      - `"bicycle"Bicycle`

    - `Double TimeSeconds`

      Travel time budget in seconds

    - `Long VerticesReached`

      Number of road network vertices within the isochrone

  - `Type Type`

    `Feature` for single contour, `FeatureCollection` for multiple contours

    - `"Feature"Feature`

    - `"FeatureCollection"FeatureCollection`

### Example

```csharp
RoutingIsochronePostParams parameters = new()
{
    Lat = 0,
    Lng = 0,
    Time = 0,
};

var response = await client.Routing.IsochronePost(parameters);

Console.WriteLine(response);
```

#### Response

```json
{
  "features": [
    {
      "geometry": {
        "coordinates": [
          2.3522,
          48.8566
        ],
        "type": "Point"
      },
      "properties": {
        "@id": "bar",
        "@type": "bar",
        "amenity": "bar",
        "cuisine": "bar",
        "name": "bar"
      },
      "type": "Feature",
      "id": "node/21154906"
    }
  ],
  "geometry": {
    "coordinates": [
      2.3522,
      48.8566
    ],
    "type": "Point"
  },
  "properties": {
    "area_m2": 0,
    "max_cost_s": 0,
    "mode": "auto",
    "time_seconds": 0,
    "vertices_reached": 0
  },
  "type": "Feature"
}
```