Hi,
we should also try to make sure that any approach here is consistent
with the upcoming groups proposal [1].
Klaus
[1]
https://github.com/cf-convention/cf-conventions/pull/145/files#diff-72315029966a0acd1d12ff8e03994c88R220
On 15/03/2019 15:19, Jim Biard wrote:
> Lars,
>
>
> Good catch! It seems that history may need to be an exception to such a
> rule. A comment attribute should also probably be considered to be an
> exception as well. Or the concept needs refinement.
>
>
> Jim
>
>
> On 3/15/19 8:48 AM, B?rring Lars wrote:
>> Dear all,
>>
>> I have come across many CMIP5 files that have the same attribute
>> [name] attached to the data variable as found in the globals.
>>
>> In particular it seems that CMOR was writing variable processing
>> history attached to the variable, and more general file processing in
>> the global history.
>>
>> I have also seen that "comment" sometimes occur both as global and as
>> variable attribute.
>>
>> If such a duplication occurs, CF writes:
>> "When an attribute appears both globally and as a variable attribute,
>> the variable?s version has precedence."
>>
>> My interpretation of this is that if there are contradictory
>> information then the variable's attribute has precedence, but
>> otherwise it does not invalidate or overshadows what is in the global
>> attribute.
>>
>> However, the data model presented in the GMD paper
>> (https://www.geosci-model-dev.net/10/4619/2017/ page 4629, [page 11],
>> under "4.1 The field construct") presents a more restrictive
>> interpretation:
>> "In the data model, we consider that netCDF global file attributes
>> apply to every data variable in the file, except where they are
>> superseded by netCDF data variable attributes with the same name."
>>
>> I understand this to mean that if the same attributes (e.g. comment or
>> history) is present both as global and variable attribute, then the
>> global attribute is overshadowed (as if it did not exist at all)?
>>
>> Is this correct? If so, is this the best solution?
>>
>> Would not concatenating the information contained in each (putting the
>> variable text first) be a more appropriate way to resolve the
>> situation (and thus specify in the data model)?
>>
>>
>> Kind regards,
>> Lars
>>
>> --
>> Lars B?rring
>> ?
>> FDr, Forskare
>> PhD, Research Scientist
>> ?
>> SMHI? /? Swedish Meteorological and Hydrological Institute
>> Rossby Centre?
>> SE - 601 76 NORRK?PING?
>> http://www.smhi.se <http://www.smhi.se/>
>> ?
>> E-post / Email:?lars.barring at smhi.se <mailto:lars.barring at smhi.se>
>> Tel / Phone: +46 (0)11 495 8604??
>> Fax: +46 (0)11 495 8001?
>> Bes?ksadress / Visiting address: Folkborgsv?gen 17
>>
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Received on Fri Mar 15 2019 - 08:33:55 GMT
