## Calculate an isochrone from a point

`client.Routing.IsochronePost(ctx, body) (*RoutingIsochronePostResponse, error)`

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

Calculate an isochrone from a point

### Parameters

- `body RoutingIsochronePostParams`

  - `Lat param.Field[float64]`

    Latitude

  - `Lng param.Field[float64]`

    Longitude

  - `Time param.Field[float64]`

    Travel time in seconds (1-7200)

  - `Format param.Field[string]`

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

  - `Mode param.Field[string]`

    Travel mode (auto, foot, bicycle)

  - `OutputFields param.Field[string]`

    Comma-separated property fields to include

  - `OutputGeometry param.Field[bool]`

    Include geometry (default true)

  - `OutputInclude param.Field[string]`

    Extra computed fields: bbox, center

  - `OutputPrecision param.Field[int64]`

    Coordinate decimal precision (1-15, default 7)

  - `OutputSimplify param.Field[float64]`

    Simplify geometry tolerance in meters

### Returns

- `type RoutingIsochronePostResponse struct{…}`

  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.

  - `Features []GeoJsonFeature`

    Array of isochrone polygon Features (multi-contour only)

    - `Geometry GeoJsonGeometry`

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

      - `Coordinates GeoJsonGeometryCoordinatesUnion`

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

        - `type GeoJsonGeometryCoordinatesPoint []float64`

          [longitude, latitude] or [longitude, latitude, elevation]

        - `type GeoJsonGeometryCoordinatesLineStringOrMultiPoint [][]float64`

          Array of [lng, lat] positions

        - `type GeoJsonGeometryCoordinatesPolygonOrMultiLineString [][][]float64`

          Array of linear rings / line strings

        - `type GeoJsonGeometryCoordinatesMultiPolygon [][][][]float64`

          Array of polygons

      - `Type GeoJsonGeometryType`

        Geometry type

        - `const GeoJsonGeometryTypePoint GeoJsonGeometryType = "Point"`

        - `const GeoJsonGeometryTypeLineString GeoJsonGeometryType = "LineString"`

        - `const GeoJsonGeometryTypePolygon GeoJsonGeometryType = "Polygon"`

        - `const GeoJsonGeometryTypeMultiPoint GeoJsonGeometryType = "MultiPoint"`

        - `const GeoJsonGeometryTypeMultiLineString GeoJsonGeometryType = "MultiLineString"`

        - `const GeoJsonGeometryTypeMultiPolygon GeoJsonGeometryType = "MultiPolygon"`

    - `Properties map[string, unknown]`

      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.

    - `Type GeoJsonFeatureType`

      Always `Feature`

      - `const GeoJsonFeatureTypeFeature GeoJsonFeatureType = "Feature"`

    - `ID string`

      Compound identifier in `type/osm_id` format

  - `Geometry GeoJsonGeometry`

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

  - `Properties RoutingIsochronePostResponseProperties`

    Isochrone metadata

    - `AreaM2 float64`

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

    - `MaxCostS float64`

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

    - `Mode RoutingIsochronePostResponsePropertiesMode`

      Travel mode used for the isochrone calculation

      - `const RoutingIsochronePostResponsePropertiesModeAuto RoutingIsochronePostResponsePropertiesMode = "auto"`

      - `const RoutingIsochronePostResponsePropertiesModeFoot RoutingIsochronePostResponsePropertiesMode = "foot"`

      - `const RoutingIsochronePostResponsePropertiesModeBicycle RoutingIsochronePostResponsePropertiesMode = "bicycle"`

    - `TimeSeconds float64`

      Travel time budget in seconds

    - `VerticesReached int64`

      Number of road network vertices within the isochrone

  - `Type RoutingIsochronePostResponseType`

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

    - `const RoutingIsochronePostResponseTypeFeature RoutingIsochronePostResponseType = "Feature"`

    - `const RoutingIsochronePostResponseTypeFeatureCollection RoutingIsochronePostResponseType = "FeatureCollection"`

### Example

```go
package main

import (
  "context"
  "fmt"

  "github.com/plazafyi/plaza-go"
  "github.com/plazafyi/plaza-go/option"
)

func main() {
  client := githubcomplazafyiplazago.NewClient(
    option.WithAPIKey("My API Key"),
  )
  response, err := client.Routing.IsochronePost(context.TODO(), githubcomplazafyiplazago.RoutingIsochronePostParams{
    Lat: githubcomplazafyiplazago.F(0.000000),
    Lng: githubcomplazafyiplazago.F(0.000000),
    Time: githubcomplazafyiplazago.F(0.000000),
  })
  if err != nil {
    panic(err.Error())
  }
  fmt.Printf("%+v\n", response.Features)
}
```

#### 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"
}
```