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Re: [HACKERS] Indexing for geographic objects?

From: selkovjr(at)mcs(dot)anl(dot)gov
To: Franck Martin <Franck(at)sopac(dot)org>
Cc: "'pgsql-general '" <pgsql-general(at)postgresql(dot)org>, "'pgsql-hackers '" <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: [HACKERS] Indexing for geographic objects?
Date: 2000-11-28 00:03:33
Message-ID: 200011280003.SAA16737@selkovjr.xnet.com (view raw or flat)
Thread:
Lists: pgsql-generalpgsql-hackers
Franck Martin wrote:
> I have already created geographical objects which contains MBR(Minimum
> Bounding Rectangle) in their structure, so it is a question of rewriting
> your code to change the access to the cube structure to the MBR structure
> inside my geoobject. (cf http://fmaps.sourceforge.net/) Look in the CVS for
> latest. I have been slack lately on the project, but I'm not forgetting it.

I see where you are aiming. I definitely want to be around when it
starts working.

> Quickly I ran through the code, and I think your cube is strictly speaking a
> box, which also a MBR.

Yes, cube is definitely a misnomer -- it suggests things are
equihedral, which they aren't. I am still looking for a short name or
an acronym that would indicate it is a box with an arbitrary number of
dimensions. With your application, you will surely benefit from a
smaller and faster code geared specifically for 3D.

> However I didn't see the case of intersection, which is the main question
> when you want to display object that are visible inside a box.

The procedure is there, it is called cube_inter, but there is no
operator for it.
 
> I suppose your code is under GPL, and you have no problem for me to use it,
> providing I put your name and credits somewhere.

No problem at all -- I will be honored if you use it. Was I careless
enough not to include a license? It's not exactly a GPL -- it's
completely unrestricted. I should have said that somewhere.

Good luck,

--Gene

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