[postgis-users] value of spatial index on 300, 000, 000 point geometries

[Luigi Castro Cardeles]

Regina,

i use M for time. I always think about Z being some sort of altitude or
height.

[]'s

Luigi Castro Cardeles


2009/5/6 Paragon Corporation <lr at pcorp.us>

> Kevin,
>
> I think you have a bogus proj install or your spatial_ref_sys table has
> some
> sort of z mentioned.
>
> I get
> "SRID=4001;POINT(-122.689717977579 49.4265525863074 5)"
>
> Though I only have proj 4.6.0 and 4.6.1 installs (tested on 1.3.3 and
> 1.4SVN) so can't be sure its not an issue with an older proj you have.
>
> Anyway does anyone actually use Z for time?  I always use M since in theory
> its not out of the question that we wouldn't transform Z since it is a
> space
> dimension.
>
> Thanks,
> Regina
>
>
>
> -----Original Message-----
> From: postgis-users-bounces at postgis.refractions.net
> [mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of Paul
> Ramsey
> Sent: Wednesday, May 06, 2009 2:04 AM
> To: PostGIS Users Discussion
> Subject: Re: [postgis-users] value of spatial index on 300, 000, 000 point
> geometries
>
> Well, our versions differ, but that means nothing :)
>
> medford=# select postgis_proj_version();
>    postgis_proj_version
> ----------------------------
>  Rel. 4.6.1, 21 August 2008
> (1 row)
>
> I'm also running 1.4SVN. And I can't recall if I installed the grid shift
> files.
>
> P.
>
> On Tue, May 5, 2009 at 10:55 PM, Kevin Neufeld <kneufeld at refractions.net>
> wrote:
> > :) So if proj doesn't have z transformation then ... I have a bogus
> > proj install or corrupt spatial ref definition?
> >
> > postgis=# select postgis_proj_version();
> >  postgis_proj_version  ------------------------- Rel. 4.4.9, 29 Oct
> > 2004
> > (1 row)
> >
> > Since my answer is different than yours, something is amiss.
> >
> >
> > Paul Ramsey wrote:
> >>
> >> On Tue, May 5, 2009 at 9:58 PM, Kevin Neufeld
> >> <kneufeld at refractions.net>
> >> wrote:
> >>
> >>>
> >>>  But (and folks can correct me if I'm wrong since the docs don't
> >>> actually
> >>> specify) transforms operate on *all* dimensions.
> >>> postgis=# select st_asewkt(st_transform('SRID=3005;POINT(1240227
> >>> 495643 5)', 4001));
> >>>                            st_asewkt
> >>>
> >>> --------------------------------------------------------------------
> >>> --
> >>> SRID=4001;POINT(-122.689717977579 49.4258574870912 533.550271589169)
> >>> (1 row)
> >>>
> >>
> >> That's news to me and my version of PostGIS:
> >>
> >> medford=# select st_asewkt(st_transform('SRID=3005;POINT(1240227
> >> 495643 5)', 4001));
> >>                       st_asewkt
> >> -------------------------------------------------------
> >>  SRID=4001;POINT(-122.689717977579 49.4265525863074 5)
> >> (1 row)
> >>
> >> My intuition was that reprojection would leave Z alone, since proj4
> >> has no z-transform capabilities.
> >>
> >> P.
> >> _______________________________________________
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> >>
> >
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