From: Thomas Knudsen <tk AT geb DOT gfy DOT ku DOT dk>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: point inside polygon detection
Date: Thu, 26 Mar 1998 18:40:30 +0100
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On Wed, 25 Mar 1998, Steve Patton wrote:

> Hi,
> 
>   Is there a quick easy way to detect whether a point lies within the
> boundaries of a 2d polygon?  Right now I'm dealing with a four sided
> polygon.  This shape could be a rectangle (at any rotation angle, or
> distortion), trapazoid, etc, any 4 sided polygon.  This has to be checked a
> LOT, so I would appreciate an efficient algorithm.  Source code is not
> neccessary, if you can give me an idea, I can run with it.  Thanks!
> 
> --
> -Steve
> Personal : http://home.att.net/~pattonl
> Business : http://home.att.net/~pattonl/digital_resources.htm
> 
> 
> 
> 

Check Wm. Randolph Franklin's highly optimized PNPOLY algorithm on
URL http://www.ecse.rpi.edu/Homepages/wrf/geom/pnpoly.html


-Thomas

--
Thomas Knudsen                         | www:  http://www.gfy.ku.dk/~tk/
National Survey and Cadastre - Denmark | e-mail:            tk AT gfy DOT ku DOT dk
Geodetic office, Rentemestervej 8      | Direct Phone:   +45 35 87 52 64
DK-2400 Copenhagen NV, Denmark         | FAX:            +45 35 87 50 52