Difference between NGF-IGN 1969 and NGF-IGN69 heights

Hello
would you please indicate what is the difference between

NGF-IGN 1969 (is this one depreciate ???)

and

NGF-IGN 1969 height (that one should use RAF18 grid)

thanks

antoine

Hi Antoine,

I’ll check it with the team and get back to you with more information.

Hi Antoine,

Thanks for your patience!

Proj is accumulating CRS and vertical datums from different registries. In this case, there are 2 IGN69 vertical datums from the EPSG and IGNF registries.

EPSG IGN69 has a grid file that can be used for height conversions, while IGNF IGN69 represents only a vertical datum without a grid. We would suggest using EPSG:5720 since it has a grid file and can provide straight conversions between ellipsoidal and orthometric heights.

1 Like