[postgis-users] 3D topology nodes?

[John Morrison]

Hello Sandro and Regina (et al);

Thank you both for solving that first problem ("when all else fails,
RTFM" :-)!!  I did some digging for info regarding pgadmin3 as kindly
suggested by Regina (see below) - hope it is useful.

Rather predictably, answering that single first question brings me to
my next two questions (I suppose this is progress after a fashion):

(1) Performance (or lack thereof): I am attempting to create topology
out of a rather large (36MPixel) SRTM elevation raster.  I am
currently using a very small tile as the processing times I am seeing
suggest using a calendar rather than a stopwatch to profile my code.
Is there some obvious thing I should be doing to speed things up?
Perhaps something analogous to how raster2pgsql emits an SQL file
rather than doing a pixel-at-a-time update?  Or perhaps I am going
about this entirely the wrong way?  (I had similar performance
problems in simply reading the raster out of PostGIS, but that was
more straightforward to work around...)

(2) Are there any "gotchas" of which I should be aware due to "no
proper 3D topology support?"  False co-planarity issues?  Limitations
to modeling road overpasses, etc?

As for pgadmin3 (which I had been using to try and figure this out
myself), I did some digging as Regina kindly suggested.  FYI I am
using revision 1.14.0.  When I select the node table's geom column,
the "Data type" as displayed in the properties window is
"geometry(1107458)."  The context menu's "properties" display shows a
data type of simply "geometry."

However, if the SQL pane is open, it shows a fragment of SQL ("ALTER
TABLE"...), including "ADD COLUMN geom geometry(PointZ, 4326)."

So it WAS visible, presuming I knew where to look (and I didn't).

Sorry, and thanks again for the help!

-jm


On Wednesday 30 May 2012, Sandro Santilli wrote:
> On Tue, May 29, 2012 at 10:01:35PM -0400, John Morrison wrote:
> > Hi;
> > 
> > Sorry if this is a dumb newbie question regarding support for 3D
> > topology (as I am relatively new to both SQL and PostGIS).
> > 
> > I am running PostGIS 2.0.1SVN r9732 on FC16/x86_64.
> > 
> > When I try to add a 3D point to a topology via either ST_AddIsoNode or
> > AddNode, I get an error of the form "Geometry has Z dimension, but
> > column does not."  Adding 2D points seems to work fine.
> 
> There's no proper 3D topology support, but you do can equip your
> primitives with a per-vertex Z value (2.5D) if you account for it
> at topology creation time. See manual page entry for CreateTopology
> on how to do that.
> 
> > pgadminIII gives a rather cryptic type of "geometry(1107456)" as the
> > data type of the "geom" column of the "node" table of my topology.
> 
> That is annoying, I would expect something like "geometry(point)"
> or "geometry(pointZ)" instead. Do types of other spatial tables
> look fine in pgadminIII or is it a general issue with any geometry
> column ?
> 
> --strk;
> 
>   ,------o-.
> 
>   |   __/  |    Delivering high quality PostGIS 2.0 !
>   |  
>   |  / 2.0 |    http://strk.keybit.net - http://vizzuality.com
> 
>   `-o------'
> 
> _______________________________________________
> postgis-users mailing list
> postgis-users at postgis.refractions.net
> http://postgis.refractions.net/mailman/listinfo/postgis-users


-- 
--- John Morrison
--- john.nmi.morrison at gmail.com