Editing Winding number (section)

=== Point in polygon ===
{{further| 1=Point in polygon#Winding number algorithm | label1=Point in polygon § Winding number algorithm}}
A point's winding number with respect to a polygon can be used to solve the [[Point in polygon#Winding number algorithm|point in polygon]] (PIP) problem – that is, it can be used to determine if the point is inside the polygon or not.

Generally, the [[Point in polygon#Ray casting algorithm|ray casting algorithm]] is a better alternative to the PIP problem as it does not require trigonometric functions, contrary to the winding number algorithm. Nevertheless, the winding number algorithm can be sped up so that it too, does not require calculations involving  trigonometric functions.<ref name="sunday">{{ cite web | last=Sunday | first=Dan | url=http://geomalgorithms.com/a03-_inclusion.html | title=Inclusion of a Point in a Polygon | year=2001 | url-status=usurped | archive-url=https://web.archive.org/web/20130126163405/http://geomalgorithms.com/a03-_inclusion.html | archive-date=26 January 2013}}</ref> The sped-up version of the algorithm, also known as Sunday's algorithm, is recommended in cases where non-simple polygons should also be accounted for.