Hello David,
I just noticed a typo in my email that might of confused some of you: I
meant to say "*shouldn't* conflict between variables you want to
aggregate" (otherwise it probably wouldn't make sense to aggregate them).
Perhaps you should treat the standard CF global attributes like the
non-standard ones and include only those that are identical across
aggregated variables.
best,
Karl
On 3/19/12 1:16 PM, David Hassell wrote:
> Hello Karl,
>
> An astute point. I confess to sweeping this under the carpet a little
> bit and ignoring (deleting) the standard CF global attributes as given
> in appendix A, but insisting that non-standard ones are identical for
> aggregated fields.
>
> This is an easy and pragmatic approach as a programmer, but probably
> not the most useful one? For me, it raises issues such as whether or
> not an attribute should be a scalar auxiliary coordinate, or could
> perhaps be 'promoted' to be one during the aggregation. Or perhaps
> such attributes should be concatenated? etc. This area is
> deliberately not regulated in our CF aggregation rules - rather
> leaving it to an implementation's, or the users, discretion, which can
> vary with application.
>
> Since a tool should be useful to the users (not just easy for
> programmers!), opinions are welcome.
>
> All the best,
>
> David
>
> ---- Original message from Karl Taylor (10AM 19 Mar 12)
>
>> Date: Mon, 19 Mar 2012 10:51:36 -0700
>> From: Karl Taylor<taylor13 at llnl.gov>
>> User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.5; rv:10.0.2)
>> Gecko/20120216 Thunderbird/10.0.2
>> To: cf-metadata at cgd.ucar.edu
>> Subject: Re: [CF-metadata] cf2cf - a new tool
>>
>> presumably this tool is limited to combining files with identical
>> global attributes? Of course the global attributes should conflict
>> between variables that you want to aggregate.
>>
>> Karl
>>
>> On 3/19/12 10:28 AM, David Hassell wrote:
>>> Hello,
>>>
>>> I'd like to advertise a hopefully useful new tool called 'cf2cf' for
>>> combining many CF-netCDF files into a single CF-netCDF file, where the
>>> input fields are aggregated into as few multidimensional netCDF
>>> variables as possible.
>>>
>>> This is a command line utility which utilizes the proposed CF
>>> aggregation rules (trac ticket #78) to combine CF fields based on
>>> their metadata. In particular differing variables' units, dimension
>>> order, dimension direction and netCDF variable names are are accounted
>>> for in the aggregation process.
>>>
>>> A quick, simple example:
>>>
>>> % cf2cf -o one_output_file.nc lots_of_input_files*.nc
>>>
>>> All details, including full documentation, more examples and
>>> installation, may be found at
>>> http://www.met.reading.ac.uk/~david/cf2cf.html
>>>
>>> This tool uses the python cf package
>>> (http://code.google.com/p/cf-python), which also makes the same CF
>>> aggregation and the CF data model (trac ticket #68) available in an
>>> API, in a memory efficient manner.
>>>
>>> Any feedback, positive or negative, on cf2cf, the CF aggregation rules
>>> and the cf python package would, of course, be most gratefully
>>> received, to help make these better.
>>>
>>> All the best,
>>>
>>> David
>>>
>>> --
>>> 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 : 0118 3785613
>>> Fax : 0118 3788316
>>> E-mail: d.c.hassell at reading.ac.uk
>>> _______________________________________________
>>> CF-metadata mailing list
>>> CF-metadata at cgd.ucar.edu
>>> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
>> _______________________________________________
>> 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 : 0118 3785613
> Fax : 0118 3788316
> E-mail: d.c.hassell at reading.ac.uk
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Received on Mon Mar 19 2012 - 14:39:25 GMT
