<HTML dir=ltr><HEAD><TITLE>[postgis-users] Centroid Within Multi Part Polygon</TITLE>
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<DIV dir=ltr><FONT face=Arial color=#000000 size=2>Simon,</FONT></DIV>
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<DIV dir=ltr><FONT face=Arial size=2>I must commend you on the very nice instructive site you have. Now for a nit-pcik. Your link to the PostGIS site is broken!</FONT></DIV>
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<DIV dir=ltr><FONT face=Arial size=2>This might be a stupid question - but it wasn't obvious to me so I will ask it.</FONT></DIV>
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<DIV dir=ltr><FONT face=Arial size=2>I presume the function you have is embedded in your</FONT></DIV>
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<DIV dir=ltr><FONT face=Arial size=2><A href="http://www.spatialdbadvisor.com/files/spatialdbadvisor_oracle_spatial_types_and_packages.zip">http://www.spatialdbadvisor.com/files/spatialdbadvisor_oracle_spatial_types_and_packages.zip</A></FONT></DIV>
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<DIV dir=ltr><FONT face=Arial size=2>But wasn't quite clear what it would be named and what .sql file to find it in or if it depends on numerous files.</FONT></DIV>
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<DIV dir=ltr><FONT face=Arial size=2>Thanks,</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2>Regina</FONT></DIV></DIV>
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<FONT face=Tahoma size=2><B>From:</B> postgis-users-bounces@postgis.refractions.net on behalf of Simon Greener<BR><B>Sent:</B> Mon 6/18/2007 6:07 PM<BR><B>To:</B> postgis-users@postgis.refractions.net<BR><B>Subject:</B> [postgis-users] Centroid Within Multi Part Polygon<BR></FONT><BR></DIV>
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<P><FONT size=2>Someone asked recently about a centroid function which guaranteed that<BR>the created centroid:<BR><BR>1. Fell within a polygon (not outside it as is the case with<BR>implementations that average the X and Y coords of an area);<BR>2. If the polygon is multi-part, put the centroid in the largest part.<BR><BR>I have just such a function but it is currently Oracle PL/SQL based. It<BR>does both of the above + also have an overloaded version which will<BR>return a multi-point object wherein each point is the centroid of each<BR>disperate part in a multi-part polygon. The functions have been heavily<BR>tested with many datasets and are pretty well guaranteed to work. I also<BR>have a Java version.<BR><BR>I do not know PostgreSQL's implementation of PL/SQL but I suspect I<BR>could convert the code pretty easily. I do not have the time at the<BR>moment to convert them but if anyone wants to download them from my<BR>website (see below) and convert them please feel free. All I ask if for<BR>a copy of the PostgreSQL implementation for hosting back on my website.<BR><BR>regards<BR>Simon<BR>--<BR>SpatialDB Advice and Solutions Architecture,<BR>Oracle Spatial, ArcSDE, Manifold GIS, Radius Topology and Studio<BR>Specialist.<BR>39 Cliff View Drive, Allens Rivulet, 7150, Tasmania, Australia.<BR>Website: www.spatialdbadvisor.com<BR> Email: simon@spatialdbadvisor.com<BR> Voice: +61 362 396397<BR>Mobile: +61 418 396391<BR>Skype: sggreener<BR>Longitude: 147.20515<BR>Latitude: -43.01530<BR>NAC:W80CK 7SWP3<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></FONT></P></DIV></BODY></HTML>
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