[Error] "Point in polygon" JS - On edges

[cavasinf]

Hi, I'm using your code of Point in Polygon in JS.

But it seems to not work in every case.

I'm currently using leaflet, and with your code I want to know if my point is IN a polygon. It works like a charm when the point is inside or in the bottom edge or in left edge.

✔️ ✔️ ✔️

But not when it's inside the top or right edge.

❌ ❌

It's maybe due to the fact that we need the "line" from the point to cross the edge, and not being on it.

[cavasinf]

@return {boolean} whether the point is in the polygon (not on the edge, just turn < into <= and > into >= for that)

Even with that, if I apply this logic it only reverse my case above :

• bottom edge ❌
• left edge ❌
• top edge ✔️
• right edge ✔️

[gerritnowald]

I think I may have solved this in the Python implementation of the algorithm. There is a singularity in the original condition which may be responsible for this. I already created a pull request for it. If you want to check if a point is on the edge, I would check this separately. You can check out my polygon module in my repositories, I have a function for that.