# @turf/length

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## length

Takes a [GeoJSON][1] and measures its length in the specified units, [(Multi)Point][2]'s distance are ignored.

### Parameters

*   `geojson` **[Feature][3]<([LineString][4] | [MultiLineString][5])>** GeoJSON to measure
*   `options` **[Object][6]** Optional parameters (optional, default `{}`)

    *   `options.units` **[string][7]** can be degrees, radians, miles, or kilometers (optional, default `kilometers`)

### Examples

```javascript
var line = turf.lineString([[115, -32], [131, -22], [143, -25], [150, -34]]);
var length = turf.length(line, {units: 'miles'});

//addToMap
var addToMap = [line];
line.properties.distance = length;
```

Returns **[number][8]** length of GeoJSON

[1]: https://tools.ietf.org/html/rfc7946#section-3

[2]: https://tools.ietf.org/html/rfc7946#section-3.1.2

[3]: https://tools.ietf.org/html/rfc7946#section-3.2

[4]: https://tools.ietf.org/html/rfc7946#section-3.1.4

[5]: https://tools.ietf.org/html/rfc7946#section-3.1.5

[6]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object

[7]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String

[8]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number

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---

This module is part of the [Turfjs project](https://turfjs.org/), an open source module collection dedicated to geographic algorithms. It is maintained in the [Turfjs/turf](https://github.com/Turfjs/turf) repository, where you can create PRs and issues.

### Installation

Install this single module individually:

```sh
$ npm install @turf/length
```

Or install the all-encompassing @turf/turf module that includes all modules as functions:

```sh
$ npm install @turf/turf
```