On Fri, Apr 11, 2008 at 4:39 PM, Frederik Ramm <[EMAIL PROTECTED]> wrote:
> Hi, > > Can anyone point me to a good algorithm for selecting points within an > > > arbitrary polygon? > > > > > > I don't have it in pseudocode, but one I've heard of casts a ray > > (horizontal > > is common) out from the point being tested and then checks the > > intersection > > of that ray against each segment of the polygon. If the total number of > > intersections is odd, then the point lies inside the polygon. If the > > number > > is even, then it's outside. This works for holes in a polygon, too. > > > > I think I saw an XSLT implementation of that in one of the OSM projects > somewhere but I tried very hard to forget ;-) > Well, I wasn't going to use XSLT for this, but now you mentioned it... ;) > > Bye > Frederik > >
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