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<TITLE>RE: [postgis-devel] Dropped DM (Time) dimension with intersections</TITLE>
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<P><FONT SIZE=2>Chris,<BR>
That was a bit of a trick question :) It tells me ST_ConvexHull is not ignoring the z-index.<BR>
<BR>
I was puzzled that convex hull supports 3-d is all since it is a GEOS function and I was under the impression no GEOS functions support 3-d. But looking at the code, looks like it is one of those ones that somebody snuck in 3d support though I haven't compared with JTS code base to be sure. Maybe Martin can comment.<BR>
<BR>
Thanks,<BR>
Regina<BR>
<BR>
-----Original Message-----<BR>
From: postgis-devel-bounces@postgis.refractions.net on behalf of Chris Hodgson<BR>
Sent: Tue 10/7/2008 2:10 PM<BR>
To: PostGIS Development Discussion<BR>
Subject: Re: [postgis-devel] Dropped DM (Time) dimension with intersections<BR>
<BR>
I think the answer is, nobody really knows, but it seemed to make as<BR>
much sense as possible given the operation being requested. If it<BR>
doesn't work for your use case then feel free to make a solid argument<BR>
for why we should give a different result and provide a robust method to<BR>
calculate it :-)<BR>
<BR>
Chris<BR>
<BR>
<BR>
Obe, Regina wrote:<BR>
> Which begs the question - what exactly does this tell me?<BR>
> <BR>
> SELECT<BR>
> ST_AsEWKT(ST_ConvexHull(ST_Collect(ST_GeomFromEWKT('LINESTRING(1 2 3,3<BR>
> 4 5, 3 6 7)'), ST_MakePoint(0, 2, 0))));<BR>
> Result<BR>
> "POLYGON((0 2 0,3 6 7,3 4 5,1 2 3,0 2 0))"<BR>
> <BR>
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