Dear Mark et al.
Yes, there are some standard names which imply string values, as Karl says.
If the standard_name table says 1, that means the quantity is dimensionless,
so it's also fine to omit the units, as Jim says.
Coordinate variables (as distinct from aux coord vars) have to be monotonic,
and that implies unique. Aux coord values do not have to be either monotonic
or unique. String-valued coord vars can only be auxiliary.
Best wishes
Jonathan
----- Forwarded message from John Caron <caron at ucar.edu> -----
> Date: Sun, 5 Oct 2014 04:37:48 -0600
> From: John Caron <caron at ucar.edu>
> To: "Hedley, Mark" <mark.hedley at metoffice.gov.uk>
> CC: "cf-metadata at cgd.ucar.edu" <cf-metadata at cgd.ucar.edu>
> Subject: Re: [CF-metadata] string valued coordinates
>
> >I understand that netCDF coordinate variables have to be strictly
> monotonic, and no-one wants to define what this means for the general case
> of strings; that is fine.
>
> in CDM, monontonicity is required to make the 1D coordinate maps
> invertible. For string valued coordinates, the equivilent requirement is
> uniqueness. Im not sure if CF data model states this or not.
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----- End forwarded message -----
Received on Mon Oct 06 2014 - 11:07:31 BST
