[Proj] proj-datumgrid-1.4 issued

Paul Kelly paul-grass at stjohnspoint.co.uk
Wed Jul 23 10:09:09 EDT 2008

On Wed, 23 Jul 2008, Richard didier wrote:

> Le Mardi 22 Juillet 2008 19:28, Paul Kelly a écrit :
>> I imagine this would be similar to my france.gsb file to convert between
>> the French NTF and RGF93 datums, documented in detail here:
>> http://www.stjohnspoint.co.uk/gis/france.htm
>> so perhaps that page would be of interest?
> Well, there is a difference between your grid and our : while your grid is
> correct and our has been built using the same overall process, our grid
> ensure the centimeter precision (they are something like 2 more iterations
> when computing the grid's nodes).

Hi Didier,
That's great! It's really good to have an "official" NTv2 file and it 
means I can now retire mine. I've added a note to the page recommending 
to use your new more precise file.



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