isPointInside about geolib HOT 6 CLOSED

That is a legitimate question. I copied the algorithm from somewhere I can't remember. Seems to be buggy. I have just found this one:
https://github.com/substack/point-in-polygon/blob/master/index.js

I think I will have a look if this one works better shortly.

from geolib.

Ok, seems to have the same issue ;)
https://github.com/substack/point-in-polygon/issues/2

So this one seems to be better:
https://github.com/mikolalysenko/robust-point-in-polygon
(holy crap, what a code!)

from geolib.

hi...should I use this npm library or not, seems to be bug in isPointInside method?

from geolib.

Depends on what you need. If you need a 100% accurate function to check whether a point is inside of a polygon or not, don't use it (yet). For everything else: sure, use it!

from geolib.

Thanks @manuelbieh

from geolib.

I experimentally implemented the great robust-point-in-polygon function from @mikolalysenko - you can use it like this:

var geolib = require('./dist/geolib.isPointInsideRobust')(require('geolib'));

var polygon = [
  {latitude: -46, longitude: 1},
  {latitude: -46, longitude: 2},
  {latitude: -47, longitude: 2},
  {latitude: -47, longitude: 1}
];

console.log(geolib.isPointInsideRobust({ latitude:-46, longitude:1}, polygon)) // --> 0
console.log(geolib.isPointInsideRobust({ latitude:-46, longitude:2}, polygon)) // --> 0
console.log(geolib.isPointInsideRobust({ latitude:-47, longitude:2}, polygon)) // --> 0
console.log(geolib.isPointInsideRobust({ latitude:-47, longitude:1}, polygon)) // --> 0

where 0 means the point is directly on the boundaries (then it's up to you whether you count it as "inside" or not), -1 means it is inside the given polygon and 1 means it is outside of the polygon.

In the browser just load the geolib.isPointInsideRobust.js after you loaded geolib.js. Then you can use geolib.isPointInsideRobust():

<script src="dist/geolib.js"></script>
<script src="dist/geolib.isPointInsideRobust.js"></script>
<script>
// use geolib.isPointInsideRobust() here
</script>

from geolib.