# @turf/line-overlap

# lineOverlap

Takes any LineString or Polygon and returns the overlapping lines between both features.

**Parameters**

-   `line1` **([Geometry](http://geojson.org/geojson-spec.html#geometry) \| [Feature](http://geojson.org/geojson-spec.html#feature-objects)<([LineString](http://geojson.org/geojson-spec.html#linestring) \| [MultiLineString](http://geojson.org/geojson-spec.html#multilinestring) \| [Polygon](http://geojson.org/geojson-spec.html#polygon) \| [MultiPolygon](http://geojson.org/geojson-spec.html#multipolygon))>)** any LineString or Polygon
-   `line2` **([Geometry](http://geojson.org/geojson-spec.html#geometry) \| [Feature](http://geojson.org/geojson-spec.html#feature-objects)<([LineString](http://geojson.org/geojson-spec.html#linestring) \| [MultiLineString](http://geojson.org/geojson-spec.html#multilinestring) \| [Polygon](http://geojson.org/geojson-spec.html#polygon) \| [MultiPolygon](http://geojson.org/geojson-spec.html#multipolygon))>)** any LineString or Polygon
-   `tolerance` **\[[number](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number)]** Tolerance distance to match overlapping line segments (in kilometers) (optional, default `0`)

**Examples**

```javascript
var line1 = turf.lineString([[115, -35], [125, -30], [135, -30], [145, -35]]);
var line2 = turf.lineString([[115, -25], [125, -30], [135, -30], [145, -25]]);

var overlapping = turf.lineOverlap(line1, line2);

//addToMap
var addToMap = [line1, line2, overlapping]
```

Returns **[FeatureCollection](http://geojson.org/geojson-spec.html#feature-collection-objects)<[LineString](http://geojson.org/geojson-spec.html#linestring)>** lines(s) that are overlapping between both features

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---

This module is part of the [Turfjs project](http://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 module individually:

```sh
$ npm install @turf/line-overlap
```

Or install the Turf module that includes it as a function:

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