[postgis-users] 3D WKB Geometries

[Chris Hodgson]

If you wanted to be real nice to those application programmers then you
could have a compile option  for this, ie. -DI_WANT_A_BROKEN_Z_MASK to use
the current z-masking, and by default compile with the corrected Z-mask. I
don't think that maintaining compatibilty with old applications that are
themselves incorrect (albeit to be compatible with the current postgis/OGR)
should be a higher priority than staying with the 'standard' and therefore
working with any other software out there that is correctly following the
standard.

Chris

----- Original Message -----
From: "Dave Blasby" <dblasby at refractions.net>
To: <postgis-users at postgis.refractions.net>
Sent: Wednesday, September 11, 2002 10:19 AM
Subject: Re: [postgis-users] 3D WKB Geometries


> Frank Warmerdam wrote:
> > I have discovered the WKB "Z" mask for geometry types is supposed to be
> > 0x80000000 not 0x8000 as has been used in the past in OGR and PostGIS.
The
> > matter was pointed out to me by Martin Daly at Cadcorp.   If you review
the
> > document (http://gdal.velocet.ca/projects/opengis/twohalfdsf.html) or
the real
> > document at OGC (99-402) you will see this.
> >
> > Assuming no one knows a good reason we shouldn't fix this bug I would
like to
> > see it corrected in the next release of OGR and PostGIS.  Can anyone
thing of
> > other OGC WKB 2.5D supporting software that might have this issue?
>
> I'm a bit worried about doing this - it could cause versioning problems
> with
> application software.  I.e. The new version of postgis/OGR will not work
> with old
> versions of application XYZ (no pun intended).
>
> The mapserver<->postgis connect always requests geometries in 2d so
> there
> shouldnt be any problems there.
>
> Is this going to affect anyone's code?
>
> dave
>
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