[CF-metadata] CF Workshop - remote participation

[Ethan Davis]

Hi all,

Remote participation information is in the individual session pages:

Session 1 (in about 3 hours)

   -
   https://2019esipsummermeeting.sched.com/event/PtPD/netcdf-cf-workshop-part-i

Ethan
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Re: [CF-metadata] Indices or Labels as Coordinate Variables

[Martin Juckes - UKRI STFC]

OK, I've raise an issue here: 
https://github.com/cf-convention/cf-conventions/issues/174


cheers,

Martin


From: CF-metadata  on behalf of Jonathan 
Gregory 
Sent: 12 July 2019 13:53:45
To: cf-metadata@cgd.ucar.edu
Subject: Re: [CF-metadata] Indices or Labels as Coordinate Variables

Dear Martin

Ah, I see. I agree that this is a defect now in our text if they have changed
what they say. I also agree that we should stick with what we've got i.e. more
restrictive, coord vars are 1D, numeric, and monotonic and called the same as
their dimension. That's our data model.

Best wishes

Jonathan

- Forwarded message from Martin Juckes - UKRI STFC 
 -

> Date: Fri, 12 Jul 2019 08:43:33 +
> From: Martin Juckes - UKRI STFC 
> To: Jonathan Gregory , "cf-metadata@cgd.ucar.edu"
>
> Subject: Re: [CF-metadata] Indices or Labels as Coordinate Variables
>
> Hello Tom, Jonathan,
>
>
> that is interesting. It looks like a change introduced in NetCDF 4 which CF 
> has not caught up with. Do you think they really mean what they say about the 
> values having to be strictly monotonic?
>
>
> The convention does say we use this term "term precisely as it is defined in 
> the NUG section on coordinate variables", but we also state that it must be 
> numeric. Perhaps we should take "precisely" out of that sentence (I think it 
> was true in NetCDF 3)? Keeping string values out of the array dimensions and 
> preserving a clear rule about monotonicity looks like the best approach to me,
>
>
> regards,
>
> Martin
>
>
>
> 
> From: CF-metadata  on behalf of Jonathan 
> Gregory 
> Sent: 10 July 2019 17:55
> To: cf-metadata@cgd.ucar.edu
> Subject: Re: [CF-metadata] Indices or Labels as Coordinate Variables
>
> Dear Tom
>
> That's interesting. I did not know or had forgotten about that Unidata
> recommendation. CF doesn't allow string-valued coordinate variables (with
> the same name as any of their dimensions), only string-valued auxiliary
> coordinate variables.
>
> Best wishes
>
> Jonathan
>
> - Forwarded message from Tom Evans  -
>
> > Date: Tue, 9 Jul 2019 23:08:46 +
> > From: Tom Evans 
> > To: Jonathan Gregory 
> > Subject: RE: [CF-metadata] Indices or Labels as Coordinate Variables
> >
> > Dear Jonathan
> >
> > Thanks very much for your response. It really did help me understand the 
> > use of coordinate values. In particular, your suggestion that an auxiliary 
> > coordinate variable (with a different name from the dimension) could be 
> > listed in the coordinate attribute of a variable is very helpful. It 
> > produces exactly the behaviour I'd look for in Panoply, for example.
> >
> > I have a follow-up question, if you don't mind:
> >
> > The Best Practices page at the Unidata site also mentions a "string-valued 
> > coordinate variable," which has the same name as its first dimension, e.g.
> >
> >char location(location, loc_len)
> >
> > where loc_len is the length of a text label for the location. The CF 
> > specification mentions a "string-valued auxiliary coordinate variable" -- 
> > something like
> >
> >char location_name(location, loc_len)
> >
> > if I'm following this correctly -- which could also be used as a coordinate 
> > in the attribute -- but it doesn't say anything about a string-valued 
> > variable with the same name as a dimension. I also haven't found any 
> > examples that use string-valued coordinate variables named the same as a 
> > dimension. Would such a variable risk conflict or confusion with the 
> > assumptions of applicactions designed to work with CF-compliant data?
> >
> > Cheers
> > Tom Evans
> >
> >
> >
> >
> >
> > [cid:image702fcb.PNG@5e3232e3.49822ae5]
> >
> >
> > Dr Tom Evans
> > Software Developer
> > T +64-7-859-1832
> >
> > National Institute of Water & Atmospheric Research Ltd (NIWA)
> > Gate 10 Silverdale Road, Hillcrest, Hamilton
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> >
> >
> > -Original Message-
> > From: CF-metadata  On Behalf Of Jonathan 
> > Gregory
> > Sent: Tuesday, 9 July 2019 12:42 AM
> > To: cf-metadata@cgd.ucar.edu
> > Subject: [CF-metadata] Indices or Labels as Coordinate Variables
> >
> > Dear Tom
> >
> > It would be a coordinate variable if it's location(location) and in that 
> > case
> > its values have to be unique and monotonic because generic