Hello,
Bounds variables associated with auxiliary coordinate variable may
also have the ancillary_variables attribute, too, I presume.
David
---- Original message from David Hassell (01PM 07 May 15)
> Date: Thu, 7 May 2015 13:31:45 +0100
> From: David Hassell <d.c.hassell at reading.ac.uk>
> To: Jonathan Gregory <j.m.gregory at reading.ac.uk>
> CC: cf-metadata at cgd.ucar.edu
> Subject: Re: [CF-metadata] Ancillary variables in coordinate variables
> (latitude, longitude, ...)
> User-Agent: Mutt/1.5.21 (2010-09-15)
>
> Hello Kristian, Jonathan and Jim,
>
> I also agree with Jonathan's observations and I think that some
> changes would be required to the conventions to make it clear that the
> ancillary_variables attribute is meaningful when data variables are
> used in other contexts (namely auxiliary coordinate and, why not,
> measure variables). Something like:
>
> * Change section 3.4 Ancillary Data to read from the beginning:
>
> "When one data variable provides metadata about the individual
> values of another data variable, auxiliary coordinate variable or
> measure variable it may be ..."
>
>
> * Allow, in appendix A, the ancillary_variables attribute to be
> meaningful on auxiliary coordinate variables and measure variables
> as well as data variables. We'd need a some new letter codes for
> that, though ...
>
> What do you think?
>
> All the best,
>
> David
>
> ---- Original message from Jonathan Gregory (06PM 06 May 15)
>
> > Date: Wed, 6 May 2015 18:09:31 +0100
> > From: Jonathan Gregory <j.m.gregory at reading.ac.uk>
> > To: cf-metadata at cgd.ucar.edu
> > Subject: Re: [CF-metadata] Ancillary variables in coordinate variables
> > (latitude, longitude, ...)
> > User-Agent: Mutt/1.5.21 (2010-09-15)
> >
> > Dear Kristian
> >
> > > In these case the feature type is a trajectory, so
> > > the latitude and longitude are auxiliary coordinates.
> > >
> > > You said that for auxiliary coordinates it could be ok, Would this mean
> > > that it could be added to the CF conventions?
> >
> > I don't think any change would be needed to the CF convention. CF allows a
> > given netCDF variable to serve as both a data variable in its own right and
> > an aux coord var of another data variable. An example of where this might be
> > useful is for an ocean model on density levels, in which depth as a function
> > of density is of interest as a data variable, but could also be an auxiliary
> > coordinate variable for other data variables. Therefore I think it would be
> > legal for your aux coord vars to have ancillary vars. Since the lat and lon
> > along a trajectory are actually dependent data variables, this feels quite
> > reasonable to me for your case. I wonder what others think.
> >
> > Cheers
> >
> > Jonathan
> >
> > > On 5 May 2015 at 18:58, Jonathan Gregory <j.m.gregory at reading.ac.uk> wrote:
> > >
> > > > Dear Kristian
> > > >
> > > > Ancillary variables are only for data variables in the current convention.
> > > > It wouldn't be illegal to use the attribute on coord variables, but CF
> > > > doesn't define what that would mean. (CF always permits any
> > > > non-standardised
> > > > attributes.)
> > > >
> > > > I wonder whether these are 1D coord variables (in the Unidata sense) or
> > > > aux coord vars (named by the coordinates attribute)? In the latter case, it
> > > > could be OK, because other data variables could be named as aux coord vars.
> > > >
> > > > Best wishes
> > > >
> > > > Jonathan
> > > >
> > > >
> > > > ----- Forwarded message from Kristian Sebasti??n <ksebastian at socib.es>
> > > > -----
> > > >
> > > > > Date: Thu, 30 Apr 2015 08:43:54 +0200
> > > > > From: Kristian Sebasti??n <ksebastian at socib.es>
> > > > > To: cf-metadata at cgd.ucar.edu
> > > > > Subject: [CF-metadata] Ancillary variables in coordinate variables
> > > > (latitude,
> > > > > longitude, ...)
> > > > >
> > > > > Dear CF community,
> > > > >
> > > > > We have some dataset with quality controls applied to the coordinate
> > > > > variables, such as latitude and longitude coordinate. The result are
> > > > > quality control variables that we associate as ancillary variables of the
> > > > > coordinate variables with the ancillary_variables attribute. For example,
> > > > > the LAT coordinate variable has the ancillary variable QC_LAT. The
> > > > dataset
> > > > >
> > > > http://thredds.socib.es/thredds/dodsC/drifter/surface_drifter/drifter_svp052-ime_svp017/L1/2014/dep0001_drifter-svp052_ime-svp017_L1_2014-05-25.nc
> > > > >
> > > > > The cf-conventions clarifies the use of the ancillary_variables attribute
> > > > > for data variables but not for coordinate variables. My question is, Is
> > > > the
> > > > > ancillary_variables attribute in coordinates variables compliant with the
> > > > > cf-conventions?
> > > > >
> > > > > Best regards,
> > > > >
> > > > > Kristian
> > > > >
> > > > > --
> > > > >
> > > > > Kristian Sebastian Blalid
> > > > > SOS Division: Data Center Technical
> > > > > Tel: 971439860 - Fax: 971439979
> > > > > E-mail: kristian.sebastian at socib.es
> > > >
> > > >
> > > >
> > > > > _______________________________________________
> > > > > CF-metadata mailing list
> > > > > CF-metadata at cgd.ucar.edu
> > > > > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
> > > >
> > > >
> > > > ----- End forwarded message -----
> > > > _______________________________________________
> > > > CF-metadata mailing list
> > > > CF-metadata at cgd.ucar.edu
> > > > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
> > > >
> > >
> > >
> > >
> > > --
> > >
> > > Kristian Sebastian Blalid
> > > SOS Division: Data Center Technical
> > > Tel: 971439860 - Fax: 971439979
> > > E-mail: kristian.sebastian at socib.es
> >
> >
> >
> > ----- End forwarded message -----
> > _______________________________________________
> > CF-metadata mailing list
> > CF-metadata at cgd.ucar.edu
> > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
>
>
> --
> David Hassell
> National Centre for Atmospheric Science (NCAS)
> Department of Meteorology, University of Reading,
> Earley Gate, PO Box 243,
> Reading RG6 6BB, U.K.
>
> Tel : +44 118 3785613
> E-mail: d.c.hassell at reading.ac.uk
--
David Hassell
National Centre for Atmospheric Science (NCAS)
Department of Meteorology, University of Reading,
Earley Gate, PO Box 243,
Reading RG6 6BB, U.K.
Tel : +44 118 3785613
E-mail: d.c.hassell at reading.ac.uk
Received on Thu May 07 2015 - 07:22:39 BST
