<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
<HTML>
<HEAD>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
<META NAME="Generator" CONTENT="MS Exchange Server version 6.5.7653.38">
<TITLE>RE: [postgis-users] Get concave hull from an array of longitudeinlatitude points</TITLE>
</HEAD>
<BODY>
<!-- Converted from text/plain format -->
<P><FONT SIZE=2>Are scratch that thought. That's not right either.<BR>
-----Original Message-----<BR>
From: postgis-users-bounces@postgis.refractions.net on behalf of Obe, Regina<BR>
Sent: Mon 11/24/2008 2:16 PM<BR>
To: PostGIS Users Discussion<BR>
Subject: RE: [postgis-users] Get concave hull from an array of longitudeinlatitude points<BR>
<BR>
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>
_______________________________________________<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>
-----------------------------------------<BR>
The substance of this message, including any attachments, may be<BR>
confidential, legally privileged and/or exempt from disclosure<BR>
pursuant to Massachusetts law. It is intended<BR>
solely for the addressee. If you received this in error, please<BR>
contact the sender and delete the material from any computer.<BR>
<BR>
<BR>
</FONT>
</P>
</BODY>
</HTML>