Jonathan:
when you say:
You could describe a standard error with a `cell_methods` entry of
`measurement: standard_deviation`, for instance, if we add `measurement`
to the standard name table, meaning the ordinal number of a measurement
of a given quantity. There does not have to a measurement dimension; using
a standard name in `cell_methods` implies that the statistic applies to
the complete range of the quantity named i.e. all possible measurements
in this case.
Can you provide an example just to make sure I understand ?
very respectfully,
randy
----------------------------------------
From: "Jonathan Gregory" <j.m.gregory at reading.ac.uk>
Sent: Monday, September 09, 2013 10:26 AM
To:
Subject: Re: [CF Metadata] #74: Allow sharing of ancillary variables among
multiple data variables
#74: Allow sharing of ancillary variables among multiple data variables
---------------------------------------+------------------------------------
Reporter: rhorne at excaliburlabs.com | Owner:
cf-conventions at lists.llnl.gov
Type: enhancement | Status: new
Priority: medium | Milestone:
Component: cf-conventions | Version:
Resolution: | Keywords: "ancillary data"
"standard name modifiers"
---------------------------------------+------------------------------------
Comment (by jonathan):
Dear all
I tend to think, partly as a result of discussion in another ticket, that
we should adopt a different solution for `number_of_observations` and
`status_flag` on the one hand, and `standard_error` and
`detection_minimum` on the other. Thus we could get rid of standard name
modifiers, as Nan says; they are awkward and have caused confusion.
As Randy says, the former two modifiers could become standard names for
dimensionless quantities. As Nan says, this can't be done for the latter
two, because they have units. Instead, I think we should put the
information into `cell_methods`. It is possible to regard standard error
and detection minimum as particular statistics in an ensemble of possible
measurements of the same quantity, I would argue. If so, `cell_methods` is
a natural place to put them, under an entry which applies to a notional
dimension that runs over the members of this population. You could
describe a standard error with a `cell_methods` entry of `measurement:
standard_deviation`, for instance, if we add `measurement` to the standard
name table, meaning the ordinal number of a measurement of a given
quantity. There does not have to a measurement dimension; using a standard
name in `cell_methods` implies that the statistic applies to the complete
range of the quantity named i.e. all possible measurements in this case.
Does this make sense to you?
A nice consequence is that this would simplify the convention, because
only the standard name and cell methods would determine the canonical
units of the quantity. At the moment, the standard name modifier has to be
considered as well.
Cheers
Jonathan
--
Ticket URL: <
https://cf-pcmdi.llnl.gov/trac/ticket/74#comment:40>
CF Metadata <
http://cf-pcmdi.llnl.gov/>
CF Metadata
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