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]> 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] [[email protected]]
> On Behalf Of Frank Warmerdam [[email protected]]
> Sent: Thursday, 6 December 2012 1:18 p.m.
> To: PROJ.4 and general Projections Discussions; GeoTIFF; gdal-dev;
> [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]
> 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]
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Software Developer
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