[Proj] HARN nadgrid files
sebastic at xs4all.nl
Thu Dec 22 15:50:15 EST 2016
On 12/22/2016 09:40 PM, Richard Greenwood wrote:
> One group of transformations that seems to have been ignored for a number
> of years is applying the HARN hpgn grids in the Proj epsg file. For example
> the Proj epsg entry for epsg:3758 uses +towgs84=0,0,0,0,0,0,0 but I believe
> that is should use +nadgrids=wyhpgn.gsb, or at least that's what I change
> it to, which produces results that match NADCON.
> Is anyone aware of a reason that nadgrids are not referenced in the epsg
> file? Is it maybe just an oversight, something that nobody ever got around
> to? Or because distributing nadgrids would become burdensome?
wyhpgn.gsb is not included in proj-datumgrids, so referencing it in the
epsg file in proj doesn't make sense as the definition would be unusable.
If wyhpgn.gsb is licensed freely enough to be included in
proj-datumgrids, updating the definition to use it is an option.
I've looked for the authoritative source for wyhpgn.gsb but didn't find
it. Who provides the file and under which license?
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