Dear Jim In Appendix A it does not say that the flag attributes are allowed for coordinate variables - it has just "D" in the "Use" column. This is not an argument why they shouldn't be if there is a need, but they weren't introduced with that in mind. The use which you suggested for Martin's case is a good idea, but I think it would need a change to the convention.
Best wishes Jonathan ----- Forwarded message from Jim Biard <[email protected]> ----- > Date: Wed, 12 Oct 2016 14:58:11 -0400 > From: Jim Biard <[email protected]> > To: [email protected] > Subject: Re: [CF-metadata] Missing data bins in histograms > User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:45.0) > Gecko/20100101 Thunderbird/45.4.0 > > Jonathan, > > Missing/fill values are not allowed, but I don't see any language > prohibiting flags. I'd appreciate it if you could expand on your > thoughts about why they aren't allowed. > > Grace and peace, > > Jim > On 10/12/16 1:30 PM, Jonathan Gregory wrote: > >Dear Jim > > > >That is an ingenious idea. I don't think the flag atts are currently allowed > >for coord variables, but they could be, I agree. > > > >Best wishes > > > >Jonathan > > > >----- Forwarded message from Jim Biard <[email protected]> ----- > > > >>Date: Tue, 11 Oct 2016 14:39:56 -0400 > >>From: Jim Biard <[email protected]> > >>To: [email protected] > >>Subject: Re: [CF-metadata] Missing data bins in histograms > >>User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:45.0) > >> Gecko/20100101 Thunderbird/45.4.0 > >> > >>Hi. > >> > >>Another approach could be to use flag_values and flag_meanings on > >>the coordinate variable to indicate one or more special coordinate > >>values that correspond to any number of "missing data" or "out of > >>bounds" bins. These attributes aren't forbidden by CF, and > >>everything should be fine as long as the coordinate variable remains > >>monotonic. > >> > >>Grace and peace, > >> > >>Jim > >> > >>On 10/11/16 8:41 AM, [email protected] wrote: > >>>Hello, > >>> > >>>the CF standard name list has two "histogram_.... " entries, and in the > >>>CMIP6 data request we may need to add a third, a > >>>histogram_of_cloud_top_height. Besides the standard name, we also need, > >>>for this new variable, a method of encoding the "missing data" bin in the > >>>histogram. That is, the histogram should record frequency in 16 data bins > >>>and one additional bin for the frequency of missing data. > >>> > >>>Can we define a "missing_data_index" attribute for histogram variables, > >>>and use this to indicate that the first bin in the array has this special > >>>purpose. It might be more pythonic to put the _FillValue in the coordinate > >>>value for the missing data bin, but I suspect that this would cause > >>>substantial problems for many software packages. > >>> > >>>regards, > >>>Martin > >>>_______________________________________________ > >>>CF-metadata mailing list > >>>[email protected] > >>>http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata > >>-- > >>CICS-NC <http://www.cicsnc.org/> Visit us on > >>Facebook <http://www.facebook.com/cicsnc> *Jim Biard* > >>*Research Scholar* > >>Cooperative Institute for Climate and Satellites NC <http://cicsnc.org/> > >>North Carolina State University <http://ncsu.edu/> > >>NOAA National Centers for Environmental Information <http://ncdc.noaa.gov/> > >>/formerly NOAA’s National Climatic Data Center/ > >>151 Patton Ave, Asheville, NC 28801 > >>e: [email protected] <mailto:[email protected]> > >>o: +1 828 271 4900 > >> > >>/Connect with us on Facebook for climate > >><https://www.facebook.com/NOAANCEIclimate> and ocean and geophysics > >><https://www.facebook.com/NOAANCEIoceangeo> information, and follow > >>us on Twitter at @NOAANCEIclimate > >><https://twitter.com/NOAANCEIclimate> and @NOAANCEIocngeo > >><https://twitter.com/NOAANCEIocngeo>. / > >> > >> > >>_______________________________________________ > >>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 > > -- > CICS-NC <http://www.cicsnc.org/> Visit us on > Facebook <http://www.facebook.com/cicsnc> *Jim Biard* > *Research Scholar* > Cooperative Institute for Climate and Satellites NC <http://cicsnc.org/> > North Carolina State University <http://ncsu.edu/> > NOAA National Centers for Environmental Information <http://ncdc.noaa.gov/> > /formerly NOAA’s National Climatic Data Center/ > 151 Patton Ave, Asheville, NC 28801 > e: [email protected] <mailto:[email protected]> > o: +1 828 271 4900 > > /Connect with us on Facebook for climate > <https://www.facebook.com/NOAANCEIclimate> and ocean and geophysics > <https://www.facebook.com/NOAANCEIoceangeo> information, and follow > us on Twitter at @NOAANCEIclimate > <https://twitter.com/NOAANCEIclimate> and @NOAANCEIocngeo > <https://twitter.com/NOAANCEIocngeo>. / > > > _______________________________________________ > 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
