Hi Charlie,
> the strings "maximum_absolute_value", "minimum_absolute_value",
> and "mean_absolute_value". I suggest CF adopt this, or some
> variant pursuant to discussion.
Many apologies - for some reason, I failed to register this crucial
sentence when I replied. I suppose that it's good that the same names
were arrived at without prior knowledge.
No objections from me, then.
All the best,
David
---- Original message from Charlie Zender (04PM 19 Feb 15)
> Date: Thu, 19 Feb 2015 16:39:15 -0800
> From: Charlie Zender <zender at uci.edu>
> To: David Hassell <d.c.hassell at reading.ac.uk>
> CC: CF Metadata Mail List <cf-metadata at cgd.ucar.edu>
> Subject: Re: [CF-metadata] New cell_methods: mabs/mibs/mebs?
> User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101
> Thunderbird/31.4.0
>
> Hello David,
>
> I use mabs/mebs/mibs as shorthand, not as cell_methods.
> I suggest, and NCO implements, cell_methods with the longer
> versions that you prefer. The command line operators of NCO
> accept either full or abbreviated versions (to save typing
> when conducting the operation itself).
>
> Now I see what you mean by the sentence in the appendix.
> It could be read either way, and I read it the wrong way.
> So I like your suggestion to clarify it.
>
> Charlie
>
> On 02/19/2015 04:27 PM, David Hassell wrote:
> >Dear Charlie,
> >
> >I for one have no objection, in general, to new cell methods - I don't
> >think that there are enough.
> >
> >Your suggestions (mabs/mibs/mebs) are clearly well defined, though I'm
> >personally not so keen on the use of abbreviations. I've not seen
> >these terms before, and wouldn't have guessed what they all mean. This
> >is contrary to all of the other cell methods, which are unabbreviated
> >and, I suspect, nearly universally understood.
> >
> >I dislike typing as much as anyone, but spelling them out is only 1 to
> >4 characters more than typing standard_deviation, the current longest
> >method name:
> >
> >standard_deviation
> >mean_absolute_value
> >minimum_absolute_value
> >maximum_absolute_value
> >
> >These terms seem nicely self describing to me. Do you think this is an
> >option?
> >
> >>There appears to be an error in the draft 1.7 document. The sentence
> >>describing Appendix E (the cell-methods appendix) says "In the Units
> >>column, u indicates the units of the physical quantity before the
> >>method is applied." Actually the units column entries are valid
> >>_after_ the method is applied. Variance is the only method for which
> >>this currently matters. This can be addressed independently of the
> >>rest of the cell_methods suggestions proposed here.
> >
> >I think that this is OK. The column contains units after the method is
> >applied, defined in terms of the original units ('u'). However, I
> >agree that the terse description can mislead (as it did me just
> >now!). How about replacing:
> >
> > "In the Units column, 'u' indicates the units of the physical
> > quantity before the method is applied."
> >
> >with something like:
> >
> > "The Units column contains the units of the physical quantity after
> > the method is applied, in terms of 'u', the units before the method
> > is applied."
> >
> >
> >All the best,
> >
> >David
> >
> >
> >---- Original message from Charlie Zender (11AM 19 Feb 15)
> >
> >>Date: Thu, 19 Feb 2015 11:56:22 -0800
> >>From: Charlie Zender <zender at uci.edu>
> >>To: CF Metadata Mail List <cf-metadata at cgd.ucar.edu>
> >>Subject: [CF-metadata] New cell_methods: mabs/mibs/mebs?
> >>User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:31.0)
> >> Gecko/20100101 Thunderbird/31.4.0
> >>
> >>Dear CF-ers,
> >>
> >>The statistics mabs/mibs/mebs stand for "Maximum absolute value",
> >>"Minimum absolute value", and "Mean absolute value", respectively.
> >>They are similar to max/min/mean statistics, and they can be useful
> >>in characterizing data when one wants positive-definite metrics.
> >>mebs (unlike mean) does not allow positive and negative values to
> >>compensate eachother. Unlike rms, mebs not does weight outliers
> >>quadratically. NCO (version 4.4.8) implements mabs/mibs/mebs as
> >>fundamental statistics (like max/min/mean/rms), and annotates the
> >>cell_methods attribute of variables reduced by these statistics with
> >>the strings "maximum_absolute_value", "minimum_absolute_value", and
> >>"mean_absolute_value". I suggest CF adopt this, or some variant
> >>pursuant to discussion.
> >>
> >>So I guess this is a request for discussion.
> >>The relevant portions of CF are
> >>http://cfconventions.org/Data/cf-conventions/cf-conventions-1.7/build/cf-conventions.html#cell-methods
> >>http://cfconventions.org/Data/cf-conventions/cf-conventions-1.7/build/cf-conventions.html#appendix-cell-methods
> >>The modifications that would be needed seem straightforward:
> >>mention mabs/mebs/mibs in the text and then enlarge the existing
> >>cell_methods table table by three rows.
> >>
> >>There appears to be an error in the draft 1.7 document. The sentence
> >>describing Appendix E (the cell-methods appendix) says "In the Units
> >>column, u indicates the units of the physical quantity before the
> >>method is applied." Actually the units column entries are valid
> >>_after_ the method is applied. Variance is the only method for which
> >>this currently matters. This can be addressed independently
> >>of the rest of the cell_methods suggestions proposed here.
> >
> >I think that this is OK. The column contains units after the method is
> >applied, defined in terms of the original units ('u'). However, the
> >terse description is misleading on first reading. How about something
> >like:
> >
> >"In the Units column are the units of the physical quantity after the
> > method is applied, in terms of 'u', the units before the method is
> > applied."
> >
> >>Best,
> >>Charlie
> >>--
> >>Charlie Zender, Earth System Sci. & Computer Sci.
> >>University of California, Irvine 949-891-2429 )'(
> >>_______________________________________________
> >>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
> >
>
> --
> Charlie Zender, Earth System Sci. & Computer Sci.
> University of California, Irvine 949-891-2429 )'(
--
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 Fri Feb 20 2015 - 01:55:47 GMT
