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<TITLE>RE: [postgis-users] Get concave hull from an array of longitude inlatitude points</TITLE>
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<P><FONT SIZE=2>Evidentally its this thing<BR>
<A HREF="http://ubicomp.algoritmi.uminho.pt/local/concavehull.html">http://ubicomp.algoritmi.uminho.pt/local/concavehull.html</A><BR>
<BR>
So I guess basically you take the boundary and you get rid of points<BR>
that have points sitting to the right/left/top/or bottom of it and then<BR>
you form a polygon from the remaining points.<BR>
<BR>
Well at least that is what it seems like to me visually. Just not quite sure how to program such a thing without writing yuck procedural code.<BR>
<BR>
Hope that helps,<BR>
Regina<BR>
<BR>
<BR>
-----Original Message-----<BR>
From: postgis-users-bounces@postgis.refractions.net on behalf of Martin Davis<BR>
Sent: Mon 11/24/2008 1:58 PM<BR>
To: PostGIS Users Discussion<BR>
Subject: Re: [postgis-users] Get concave hull from an array of longitude inlatitude points<BR>
<BR>
What's a concave hull?<BR>
<BR>
Ales Kecman wrote:<BR>
> Hi!<BR>
><BR>
><BR>
> I'm new to Postgis and would really like to get some help on getting a<BR>
> concave hull from an array of points.<BR>
><BR>
> For example:<BR>
><BR>
> I have an array of points - longitude and latitude of buildings in<BR>
> particular area in the city. I already managed to get a convex hull<BR>
> polygon from this array of points, but this is not really helpful.<BR>
> What I'm trying to get is some kind of concave hull polygon from an<BR>
> array of points, which I would further like to use in Google Earth kml<BR>
> file.<BR>
><BR>
> Thanks.<BR>
> ------------------------------------------------------------------------<BR>
><BR>
> _______________________________________________<BR>
> postgis-users mailing list<BR>
> postgis-users@postgis.refractions.net<BR>
> <A HREF="http://postgis.refractions.net/mailman/listinfo/postgis-users">http://postgis.refractions.net/mailman/listinfo/postgis-users</A><BR>
> <BR>
<BR>
--<BR>
Martin Davis<BR>
Senior Technical Architect<BR>
Refractions Research, Inc.<BR>
(250) 383-3022<BR>
<BR>
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