[Proj] PROJ: Further help with the swisstopo NTv2 grid

Melita Kennedy mkennedy2 at earthlink.net
Fri Feb 3 10:54:55 EST 2012

>Date: Wed, 1 Feb 2012 14:15:41 +0100
>From: Sandro Santilli <strk at keybit.net>
>Subject: Re: [Proj] PROJ: Further help with the swisstopo NTv2 grid
>	shift ?
>To: Melita Kennedy <mkennedy2 at earthlink.net>,	"PROJ.4 and general
>	Projections Discussions" <proj at lists.maptools.org>
>On Wed, Feb 01, 2012 at 04:31:03AM -0800, Melita Kennedy wrote:
>> One method would be to calculate the CH1903+ to WGS84 offset for each NTv2 grid point, concatenate them with the offsets from the original file and build a new NTv2 file. EPSG lists a 1m transformation from CH1903+ to WGS84, do a code search for 1676 at http://www.epsg-registry.org. 
>Great, sounds like what I did. Still unfinished. Will post for review
>once completed.
>> Disclaimer: I'm a member of the subcommittee that maintains the dataset.
>Which dataset ? Swisstopo NTv2 or the epsg-registry ?

Ah! I'm sorry that I was unclear. The one that maintains the EPSG Geodetic Parameter Dataset. 

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