determining when a point is inside a polygon
There are many algorithms^{} to determine whether a point is inside a polygon^{} or not:

•
Connect the point at infinity with a line. If this line crosses the edges of the polygon an odd number^{} of times, the point is inside the polygon. Otherwise it is not.

•
Calculate the winding number of the polygon with the point.
These two algorithms can be used for any closed curve.
Title  determining when a point is inside a polygon 

Canonical name  DeterminingWhenAPointIsInsideAPolygon 
Date of creation  20130322 15:22:24 
Last modified on  20130322 15:22:24 
Owner  matte (1858) 
Last modified by  matte (1858) 
Numerical id  7 
Author  matte (1858) 
Entry type  Topic 
Classification  msc 5100 
Related topic  WhenIsAPointInsideATriangle 