How to add attributes to coord_system

[larsbarring]

Is there a way to add my own attributes to the coord_system of cube coordinates?

Specifically, I would like to add crs_wkt(awaiting PR #4719 ) that is part of CF since some time, and proj_string that might become part of CF sometime in the future (cf. cf-convention/discuss#43).

[trexfeathers]

From @SciTools/peloton: CoordSystems do not carry arbitrary attributes (nor can they be loaded/saved, of course). The Iris data model is pretty invested in the current approach, so making this idea work would need a big overhaul.

Xarray and NetCDF4 have the flexibility needed to do this, because they don't have any special handling for grid mapping variables.

Sorry for the inconvenience!