Finds the tangents of a polygon from a point.
npm install @turf/polygon-tangentsFinds the tangents of a [(Multi)Polygon][1] from a [Point][2].
* pt [Coord][3] to calculate the tangent points from
* polygon [Feature][4]<([Polygon][1] | [MultiPolygon][5])> to get tangents from
``javascript
var polygon = turf.polygon([[[11, 0], [22, 4], [31, 0], [31, 11], [21, 15], [11, 11], [11, 0]]]);
var point = turf.point([61, 5]);
var tangents = turf.polygonTangents(point, polygon)
//addToMap
var addToMap = [tangents, point, polygon];
`
Returns [FeatureCollection][6]<[Point][2]> Feature Collection containing the two tangent points
[1]: https://tools.ietf.org/html/rfc7946#section-3.1.6
[2]: https://tools.ietf.org/html/rfc7946#section-3.1.2
[3]: https://tools.ietf.org/html/rfc7946#section-3.1.1
[4]: https://tools.ietf.org/html/rfc7946#section-3.2
[5]: https://tools.ietf.org/html/rfc7946#section-3.1.7
[6]: https://tools.ietf.org/html/rfc7946#section-3.3
---
This module is part of the Turfjs project, an open source module collection dedicated to geographic algorithms. It is maintained in the Turfjs/turf repository, where you can create PRs and issues.
Install this single module individually:
`sh`
$ npm install @turf/polygon-tangents
Or install the all-encompassing @turf/turf module that includes all modules as functions:
`sh``
$ npm install @turf/turf