# @turf/convex ## convex Takes a [Feature][1] or a [FeatureCollection][2] and returns a convex hull [Polygon][3]. Internally this uses the [convex-hull][4] module that implements a [monotone chain hull][5]. **Parameters** - `geojson` **[GeoJSON][6]** input Feature or FeatureCollection - `options` **[Object][7]** Optional parameters (optional, default `{}`) - `options.concavity` **[number][8]** 1 - thin shape. Infinity - convex hull. (optional, default `Infinity`) - `options.properties` **[Object][7]** Translate Properties to Feature (optional, default `{}`) **Examples** ```javascript var points = turf.featureCollection([ turf.point([10.195312, 43.755225]), turf.point([10.404052, 43.8424511]), turf.point([10.579833, 43.659924]), turf.point([10.360107, 43.516688]), turf.point([10.14038, 43.588348]), turf.point([10.195312, 43.755225]) ]); var hull = turf.convex(points); //addToMap var addToMap = [points, hull] ``` Returns **[Feature][9]<[Polygon][10]>** a convex hull [1]: https://tools.ietf.org/html/rfc7946#section-3.2 [2]: https://tools.ietf.org/html/rfc7946#section-3.3 [3]: https://tools.ietf.org/html/rfc7946#section-3.1.6 [4]: https://github.com/mikolalysenko/convex-hull [5]: http://en.wikibooks.org/wiki/Algorithm_Implementation/Geometry/Convex_hull/Monotone_chain [6]: https://tools.ietf.org/html/rfc7946#section-3 [7]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object [8]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number [9]: https://tools.ietf.org/html/rfc7946#section-3.2 [10]: https://tools.ietf.org/html/rfc7946#section-3.1.6 --- 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/convex ``` Or install the Turf module that includes it as a function: ```sh $ npm install @turf/turf ```