Javier,
Is there already a way to define a geoid model interpolated in
projected coordinates?
(some "small" countries, with just one projection, define their geoid
models in that projected CRS. Recreating the grid in a geographic one
adds some error)
I see that
https://proj.org/en/stable/operations/transformations/gridshift.html
was added in 9.2.0, but I only see these options:
HORIZONTAL_OFFSET,
GEOGRAPHIC_3D_OFFSET,
ELLIPSOIDAL_HEIGHT_OFFSET,
VERTICAL_OFFSET_GEOGRAPHIC_TO_VERTICAL,
VERTICAL_OFFSET_VERTICAL_TO_VERTICAL.
I am not sure if any of those apply as
"VERTICAL_OFFSET_PROJECTED_TO_VERTICAL".
This is a bit untested area. VERTICAL_OFFSET_GEOGRAPHIC_TO_VERTICAL
should be the one to use I believe.
In case it is possible, how would be the insertion of the
transformation in proj.db? (something like
https://github.com/OSGeo/PROJ/blob/master/data/sql/grid_transformation_custom.sql#L71)
You likely need to use a PROJString with +proj=gridshift +grids=...
Even
--
http://www.spatialys.com
My software is free, but my time generally not.
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