[postgis-devel] Dropped DM (Time) dimension with intersections

[Obe, Regina]

Chris,
That was a bit of a trick question :)  It tells me ST_ConvexHull is not ignoring the z-index.

 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.

Thanks,
Regina

-----Original Message-----
From: postgis-devel-bounces at postgis.refractions.net on behalf of Chris Hodgson
Sent: Tue 10/7/2008 2:10 PM
To: PostGIS Development Discussion
Subject: Re: [postgis-devel] Dropped DM (Time) dimension with intersections
 
I think the answer is, nobody really knows, but it seemed to make as 
much sense as possible given the operation being requested. If it 
doesn't work for your use case then feel free to make a solid argument 
for why we should give a different result and provide a robust method to 
calculate it :-)

Chris


Obe, Regina wrote:
> Which begs the question - what exactly does this tell me?
>  
> SELECT 
> ST_AsEWKT(ST_ConvexHull(ST_Collect(ST_GeomFromEWKT('LINESTRING(1 2 3,3 
> 4 5, 3 6 7)'), ST_MakePoint(0, 2, 0))));
> Result
> "POLYGON((0 2 0,3 6 7,3 4 5,1 2 3,0 2 0))"
>  
_______________________________________________
postgis-devel mailing list
postgis-devel at postgis.refractions.net
http://postgis.refractions.net/mailman/listinfo/postgis-devel



-----------------------------------------
The substance of this message, including any attachments, may be
confidential, legally privileged and/or exempt from disclosure
pursuant to Massachusetts law. It is intended
solely for the addressee. If you received this in error, please
contact the sender and delete the material from any computer.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/postgis-devel/attachments/20081007/b90807ff/attachment.html>