[PROJ] Implementation of NADCON5 transformations for USA

[Javier Jimenez Shaw]

Thanks Even and everybody else involved in this development. It is great
news. Another step that makes PROJ a reference in the sector. And it is
open source!

To the users that experience differences, this will be a good time to
know/learn the different versions of NAD83... and use the right one ;)

Good work!

On Fri, 16 Dec 2022, 04:02 Even Rouault, <even.rouault at spatialys.com> wrote:

> Hi,
>
> I just wanted to point to https://github.com/OSGeo/PROJ/pull/3510 which
> implements the NADCON5 transformations, with a corresponding pull
> request to PROJ-data to add  the grids as GeoTIFF files, for USA
> geodetic datums NAD27 --> NAD83(86) --> NAD83(HARN) --> NAD83(FBN) -->
> NAD83(NSRS2007) --> NAD83(2011). We can now reproduce exactly the
> results of NGS tools, such as NCAT and their online REST API.
>
> This means that the transformations within the NAD83 family which used
> to be mostly null transformations (except NAD83(86)->NAD83(HARN) where
> we currently use the HPGN grids) are no longer null. This might change
> results in your workflows once this is merged, but this is hopefully for
> the good...
>
> Even
>
> --
> http://www.spatialys.com
> My software is free, but my time generally not.
>
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