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 <[email protected]> > To: Jonathan Gregory <[email protected]> > CC: [email protected] > 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 <[email protected]> > > To: [email protected] > > 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 <[email protected]> > > > 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 <[email protected]> > > > > ----- > > > > > > > > > Date: Thu, 30 Apr 2015 08:43:54 +0200 > > > > > From: Kristian Sebasti??n <[email protected]> > > > > > To: [email protected] > > > > > 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: [email protected] > > > > > > > > > > > > > > > > > _______________________________________________ > > > > > CF-metadata mailing list > > > > > [email protected] > > > > > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata > > > > > > > > > > > > ----- End forwarded message ----- > > > > _______________________________________________ > > > > CF-metadata mailing list > > > > [email protected] > > > > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata > > > > > > > > > > > > > > > > -- > > > > > > Kristian Sebastian Blalid > > > SOS Division: Data Center Technical > > > Tel: 971439860 - Fax: 971439979 > > > E-mail: [email protected] > > > > > > > > ----- End forwarded message ----- > > _______________________________________________ > > CF-metadata mailing list > > [email protected] > > 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: [email protected] -- 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: [email protected] _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
