On a sort of related topic, (another NZ projection :-)

EPSG:3994 supercedes EPSG:3752, as EPSG got the initial specification wrong. 
This is a projection used for the wider region around NZ, rather than the NZ 
mainland, and this projection is used primarily in ESRI to avoid 180 meridian 
issues.

I assume once QGIS picks up the new GDAL which picks up the current EPSG list, 
it will natively support 3994 instead of 3752.

I was also wondering if there is any reason that 
http://www.spatialreference.org/ref/epsg/3994/ does not include a Postgis, 
Mapserver or Proj.4 definition, and if there is any way the map there could 
show the area covered by the coordinate system rather than the longitudes not 
covered?

Thanks,

  Brent Wood



--- On Wed, 12/12/12, Jeremy Palmer <[email protected]> wrote:

From: Jeremy Palmer <[email protected]>
Subject: Re: [Qgis-developer] [gdal-dev] EPSG 8.0 Upgrade
To: "Frank Warmerdam" <[email protected]>
Cc: "gdal-dev" <[email protected]>, "[email protected]" 
<[email protected]>
Date: Wednesday, December 12, 2012, 8:34 AM

Hi Frank,

Yes it would be great if grid shifts are supported in proj.4 by default, but 
for more importantly for us within Qgis. Currently I see QGIS builds it's CRS 
database using crssync which relies on GDAL OSRExportToProj4 for creating 
proj.4 strings. Does that mean that the gdal CSV files also need to support the 
grid shift? Before I raise any tickets it would be good to know where to 
actually fix the problem.

nzgd2kgrid0005.grd is the transformation between NZGD1949 and NZGD2000, not 
WGS84 and NZGD2000. See more information here 
http://www.linz.govt.nz/geodetic/software-downloads#distortiongrid. 
nzgd2kgrid0005.grd is created from the ASCII file which can be downloaded here 
http://www.linz.govt.nz/sites/default/files/geodetic/software-downloads/nzgd2kgrid9911.zip

Cheers,
Jeremy
 
________________________________________
From: [email protected] [[email protected]] On Behalf Of Frank Warmerdam 
[[email protected]]
Sent: Saturday, 8 December 2012 8:03 a.m.
To: Jeremy Palmer
Cc: gdal-dev; [email protected]
Subject: Re: [gdal-dev] EPSG 8.0 Upgrade

Jeremy,

Unfortunately I do not automatically pickup references to grid shift files from 
the EPSG database.  To the extent these are supported it is accomplished by 
special hackery. In fact skimming the epsg file, I think the only datum for 
which grid shift files are used *by default* is NAD27.   Perhaps this would be 
a good time for me to review how to utilize at least the grid shift files we 
are distributing with PROJ.4 like ntf_r93.gsb and nzgd2kgrid0005.gsb.

Hmm, I am getting the impression that nzgd2kgrid0005.grd is actually the 
transformation between NZGD2000 and WGS84 and that we would actually need 
another file - possibly something like Nzgd49ToNzgd2K.gdc to support NZGD1949 - 
is that right?

I'd suggest you file a ticket in the PROJ.4 Trac on this issue with suggestions 
on how to proceed.

Best regards,
Frank



On Thu, Dec 6, 2012 at 10:12 AM, Jeremy Palmer 
<[email protected]<mailto:[email protected]>> wrote:
HI Frank,

Thanks that's great news. Has this upgrade now started supporting data shift 
grids, such as NZGD2000<->NZGD1949?

Cheers
Jeremy
________________________________________
From: [email protected]<mailto:[email protected]> 
[[email protected]<mailto:[email protected]>] On 
Behalf Of Frank Warmerdam [[email protected]<mailto:[email protected]>]
Sent: Thursday, 6 December 2012 1:18 p.m.
To: PROJ.4 and general Projections Discussions; GeoTIFF; gdal-dev; 
[email protected]<mailto:[email protected]>
Subject: [gdal-dev] EPSG 8.0 Upgrade

Folks,

At the request of Howard Butler, I have upgraded PROJ.4, libgeotiff, and
GDAL to use the EPSG 8.0 database in development "trunk".

This was accomplished, as usual based on the process described here:

   http://svn.osgeo.org/metacrs/geotiff/trunk/libgeotiff/csv/README

Amoung other things this will result in some datums having new preferred
datum shift solutions.  Upgrade with care.

Best regards,
--
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, 
[email protected]<mailto:[email protected]>
light and sound - activate the windows | http://home.gdal.org/warmerda
and watch the world go round - Rush    | Geospatial Software Developer

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--
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, 
[email protected]<mailto:[email protected]>
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Software Developer
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