[postgis-users] WKT polygon and interior ring orientation

[Kevin Neufeld]

No, it looks like the PostGIS point-in-polygon shortcut uses Dan Sunday's algorithm, "Fast Winding Number Inclusion of a 
Point in a Polygon".

http://softsurfer.com/Archive/algorithm_0103/algorithm_0103.htm#Winding%20Number

-- Kevin

Sufficool, Stanley wrote:
> Does ring orientation matter when you are calculating point in poly?
> When you calc a point in poly, do you take the sum of vertex angles from
> point to poly vertex and if sum of angles is >= 360 then point is in
> poly?
>