[CF-metadata] files with no data variables

[Karl E.Taylor]

Dear Jonathan,

Jonathan Gregory wrote:
> 
> It is therefore possible to store the grid information in a separate file
> without introducing any more concepts in CF, though I agree we could comment
> and provide guidance on this possibility. Up to now we have taken the view that
> CF deals with the correct construction of a single netCDF file by itself, not a
> collection of files. 

I disagree that additional concepts are not needed in CF when some of the 
descriptive information is contained in other files.  Wouldn't it be easier 
to automatically find this information if the name of the file were included
as an attribute? I would attach the attribute to the variable.  I think
I wouldn't include the full path information ... applications could allow the
user to set the path where the auxiliary or supplementary should be searched
for.


> It isn't possible, however, to create an instance of a
> "grid", defined by a combination of coordinate variables (and perhaps a grid
> mapping), but containing no data. I don't know whether we need to be able to do
> this, but that's what my abstract variable proposal is about.

I don't know either;  anyone else think this is needed?

cheers,
Karl