The Unidata recommendations at
(
http://www.unidata.ucar.edu/software/netcdf/conventions.html) made
sense to me:
If your conventions are hierarchical (general followed by more
specialized) use the '/'.
or
If your conventions are not hierarchical, use the ',' (or space).
But I suppose you are right that it doesn't really matter. Software
that only works with UGRID-0.9 I'm sure will be happy if it finds
UGRID-0.9 somewhere in the Conventions string.
On Fri, Mar 13, 2015 at 2:28 PM, Nan Galbraith <ngalbraith at whoi.edu> wrote:
> Hmmm, interesting point, Rich. The ACDD and OceanSITES conventions both
> extend
> CF, and both recommend a comma separated list in the Conventions attribute.
>
> There doesn't seem to be an explicit prohibition in the document against
> using commas
> for extensions of other conventions. It seems to me that the '/' in
> conventions.html
> refers to the old disk directory and URL scheme, where the documentation for
> XXX
> would be located at /pub/netcdf/Conventions/XXX and the Time_series
> extension
> would be at /pub/netcdf/Conventions/XXX/Time_series.
>
> Does the / convey any useful information? As long as both CF and UGRID are
> listed,
> isn't that enough?
>
> I can't see any reason why unidata chooses to promote 2 versions of this,
> except maybe
> for profiles, in which some of the requirements of a convention are dropped,
> or assumed
> to have default values, and not required by the profile.
>
> Cheers - Nan
>
>
>
>
> On 3/13/15 1:59 PM, Signell, Richard wrote:
>>
>> David,
>>
>> I looked at this a bit and I'm not sure that
>> http://cf-trac.llnl.gov/trac/ticket/76 actually captures this need, as
>> UGRID is intended to *extend* CF, rather than a stand-alone
>> alternative.
>>
>> For situations like CF and UGRID, which *extends* CF, it would appear
>> from this guidance
>> (http://www.unidata.ucar.edu/software/netcdf/conventions.html)
>> that the foward slash separator should be used:
>>
>> Conventions = "CF-1.6/UGRID-0.9"
>>
>> This is discussed more in github issue
>>
>> (https://github.com/ugrid-conventions/ugrid-conventions/issues/11#issuecomment-79157891)
>>
>> -Rich
>>
>> P.S. Chris also points out that the current CF-1.6 document
>>
>> http://cfconventions.org/Data/cf-conventions/cf-conventions-1.6/build/cf-conventions.html
>> there is an unfortunate error/typo that says the convention should look
>> like
>>
>> Conventions = " CF-1.6 " (e.g. with spaces on either side of the quotes)
>>
>> Happily, this is gone in the 1.7 version at:
>>
>> http://cfconventions.org/Data/cf-conventions/cf-conventions-1.7/build/cf-conventions.html
>>
>> But perhaps it would be good to edit the CF-1.6 doc if that is indeed a
>> typo.
>>
>> On Fri, Mar 6, 2015 at 7:21 AM, David Hassell <d.c.hassell at reading.ac.uk>
>> wrote:
>>>
>>> Hello Martin,
>>>
>>> Good news - this is covered by trac ticket #76 "More than one name in
>>> Conventions attribute" (http://cf-trac.llnl.gov/trac/ticket/76).
>>>
>>> This has been accepted and should be in 1.7 (if it wasn't already in
>>> 1.6?):
>>>
>>> It is possible for a netCDF file to adhere to more than one set of
>>> conventions, even when there is no inheritance relationship among
>>> the conventions. In this case, the value of the Conventions
>>> attribute may be a single text string containing a list of the
>>> convention names separated by blank space (recommended) or commas
>>> (if a convention name contains blanks). This is the Unidata
>>> recommended syntax from NetCDF Users Guide, Appendix B. If the
>>> string contains any commas, it is assumed to be a comma-separated
>>> list.
>>>
>>> For example:
>>>
>>> :Conventions = "CF-1.6 ACDD-1.0" ;
>>>
>>>
>>> All the best,
>>>
>>> David
>>>
>>> ---- Original message from martin.juckes at stfc.ac.uk (12PM 06 Mar 15)
>>>
>>>> Date: Fri, 6 Mar 2015 12:02:29 +0000
>>>> From: martin.juckes at stfc.ac.uk
>>>> To: cf-metadata at cgd.ucar.edu
>>>> Subject: [CF-metadata] Applying multiple conventions
>>>>
>>>> Hello,
>>>>
>>>> There is a proposal floating around to use the UGRID conventions for
>>>> unstructured grids in CMIP6 data. One issue is that the CF Convention
>>>> specifies a specific string for the "Conventions" and the UGRID convention
>>>> specific a different specific string. Is there any chance of modifying CF to
>>>> accept, e.g. Conventions = "CF-1.8, UGRID-0.9"?
>>>>
>>>> regards,
>>>> Martin
>>>>
>>>>
>
>
> --
> *******************************************************
> * Nan Galbraith Information Systems Specialist *
> * Upper Ocean Processes Group Mail Stop 29 *
> * Woods Hole Oceanographic Institution *
> * Woods Hole, MA 02543 (508) 289-2444 *
> *******************************************************
>
>
>
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--
Dr. Richard P. Signell (508) 457-2229
USGS, 384 Woods Hole Rd.
Woods Hole, MA 02543-1598
Received on Fri Mar 13 2015 - 12:57:36 GMT
