[postgis-devel] assumptions of &&& operator for missing dimensions
Rémi Cura
remi.cura at gmail.com
Tue Feb 24 08:06:34 PST 2015
Clearly 2 for me !
Cheers,
Rémi-C
2015-02-24 17:05 GMT+01:00 Sandro Santilli <strk at keybit.net>:
> On Tue, Feb 24, 2015 at 04:26:02PM +0100, Even Rouault wrote:
> > Le mardi 24 février 2015 16:15:53, Sandro Santilli a écrit :
> > > On Tue, Feb 24, 2015 at 08:09:26AM -0500, Paul Ramsey wrote:
> > > > Well, the old semantic has been there since 2.0, which is a very long
> > > > time. A further question for it would be: what do the next functions
> do?
> > > > What does a distance calculation between a 2d and 3d object return?
> does
> > > > it also respect that semantic?
> > >
> > > I just checked and ST_3DDistance is instead still confusing:
> > > select ST_3DDistance('POINT Z (0 0 10)', 'POINT (0 0)'); -- 10
> > > I think it should be 0 instead.
> >
> > As an uninformed observer, 10 or an error because of heterogenous
> dimensions
> > would seem reasonable to me. But 0 would be very surprising !
>
> How about overlap then ? Should they overlap or not ?
>
> 'POINT Z (0 0 10)' &&& 'POINT (0 0)'
>
> That's were we started, original question was,
> which one do you prefer:
>
> 1. Missing dimension is unknown, return NULL
> 2. Missing dimension is infinite, overlaps everything
> 3. Missing dimension is empty, overlaps nothing
> 4. An impossible comparison was requested, raise exception
>
> On Thu, Feb 19, 2015 at 09:04:16AM -0800, Paul Ramsey wrote:
> > My preference was always to allow, for example,
> > a 2d query box to extract a 3d column of data from a volume
> > of points, and I would have implemented that way if I could.
> > Now, what i cannot tell you, is why I felt I couldn’t…
>
> --strk;
> _______________________________________________
> postgis-devel mailing list
> postgis-devel at lists.osgeo.org
> http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-devel
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/postgis-devel/attachments/20150224/c161ad26/attachment.html>
More information about the postgis-devel
mailing list