gtzinos / robust-point-in-polygon

Exactly test if a point is inside, outside or on the boundary of a polygon

robust-point-in-polygon

Exactly determines if a point is contained in a 2D polygon.

Example

var classifyPoint = require("robust-point-in-polygon")
var polygon = [ [ 1, 1 ], [ 1, 2 ], [ 2, 2 ], [ 2, 1 ] ]

console.log(
  classifyPoint(polygon, [1.5, 1.5]),
  classifyPoint(polygon, [1, 2]),
  classifyPoint(polygom, [100000, 10000]))

Output:

-1 0 1

Install

npm install robust-point-in-polygon

API

require("robust-point-in-polygon")(loop, point)

Tests if a point is contained in the interior of a simple polygon

• loop is an array of vertices for the polygon
• point is a 2D point which is classified against the polygon

Returns An integer which determines the position of point relative to polygon. This has the following interpretation:

• -1 if point is contained inside loop
• 0 if point is on the boundary of loop
• 1 if point is outside loop

Credits

(c) 2014 Mikola Lysenko. MIT License