determine if a point is inside a polygon with a ray intersection counting algorithm
npm install point-in-polygonDetermine if a point is inside of a polygon.
This module casts a semi-infinite ray from the inquiry point and counts intersections,
based on
this algorithm.
If you need a numerically robust solution and are willing to trade some performance for it,
use robust-point-in-polygon.
`` js
var pointInPolygon = require('point-in-polygon');
var polygon = [ [ 1, 1 ], [ 1, 2 ], [ 2, 2 ], [ 2, 1 ] ];
console.log(pointInPolygon([ 1.5, 1.5 ], polygon)); // true
console.log(pointInPolygon([ 4.9, 1.2 ], polygon)); // false
console.log(pointInPolygon([ 1.8, 1.1 ], polygon)); // true
`
` js`
var pointInPolygon = require('point-in-polygon')
var pointInPolygonFlat = require('point-in-polygon/flat')
var pointInPolygonNested = require('point-in-polygon/nested')
Return whether point is contained in polygon.
* point should be a 2-item array of coordinatespolygon
* should be an array of 2-item arrays of coordinates or a flat array of coordinatesstart
* is an offset into polygon. default 0
* is an offset into polygon. default polygon.length
The flat or nested is detected automatically. Or you can use the specific methods if you want to
skip the check.
`
npm install point-in-polygon
MIT