Re: [CF-metadata] per-variable metadata?

[Nan Galbraith]

Hi Roy and all  - Do you see a possible place for this metadata in a more structured attribute system, or somewhere else in the NetCDF file structure? Or are you thinking that we need metadata outside our CF files? Since CF has the precedent of putting other quality-related information (flag values, uncertainty, etc.) in ancillary variables, it seems (or seemed) reasonable to me to include more complete provenance info there. It might blur the line between data and metadata, but I don't see another solution without higher costs, at the moment. I'm looking forward to someone solving this, and I'm glad to hear that SeadataNet may be looking at it. Cheers - Nan On Aug/04/2011 4:13 PM, Lowry, Roy K. wrote: Hi Nan,   Encoding what I would regard as usage metadata into ancilliary variables is one solution, but I would much rather see a formalised metadata model for doing this.  As you say a standard way of doing this is long overdue. My hope is that SeadataNet II starting later this year will take on and address this challenge.  However, if anybody knows of anything already in existence that fits the bill it would be good to prevent yet another wheel being reinvented.   Cheers, Roy. From: cf-metadata-boun...@cgd.ucar.edu [cf-metadata-boun...@cgd.ucar.edu] On Behalf Of Nan Galbraith [ngalbra...@whoi.edu] Sent: 04 August 2011 19:17 To: Steve Hankin; cf-metadata@cgd.ucar.edu Cc: Jeff deLaBeaujardiere Subject: Re: [CF-metadata] per-variable metadata? Hi Steve - I'm very interested in the background discussion on this - any chance of bringing it into the foreground? I'm using ancillary variables in 2-D in situ data files to describe instruments and things like precision, accuracy, sample scheme, etc.. For temperature files from moorings where different sensor types are at different depths, I'd like to use something like TEMP:ancillary_variables = "Instrument_manufacturer Instrument_model              Instrument_sample_scheme Instrument_serial_number TEMP_qc_procedure              TEMP_accuracy TEMP_precision TEMP_resolution";  and then short INST_SN(depth) ;         INST_SN:long_name = "instrument_serial_number" ; ... etc., etc. If there's going to be a standard way to do this, I'd really like to know about it - sooner rather than than later. Thanks - Nan On 8/4/11 11:35 AM, Steve Hankin wrote: Hi Jeff, Each variable in a CF file may possess an |ancillary_variables| attribute, that points to variables that have relationships (http://cf-pcmdi.llnl.gov/documents/cf-conventions/1.5/cf-conventions.html#ancillary-data).  To attach flags to a variable, use |ancillary_variables| to point to a variable that has |flag_values||| and |flag_meanings |attributes (http://cf-pcmdi.llnl.gov/documents/cf-conventions/1.5/cf-conventions.html#flags). We have started a discussion in the background, whether an example that illustrates this should be included in the CF documentation.     - Steve ===================================================== On 7/14/2010 6:21 AM, Jeff deLaBeaujardiere wrote: In another discussion, Steve Hankin wrote: > CF generally favors attributes attached to variables over attributes attached to files This reminds me of a question I wanted to ask: does CF have any conventions regarding how to handle data that contains multiple observed quantities with different quality flags, comment fields or other attributes for each quantity? -Jeff DLB -- ******************************************************* * Nan Galbraith (508) 289-2444 * * Upper Ocean Processes Group Mail Stop 29 * * Woods Hole Oceanographic Institution * * Woods Hole, MA 02543 * *******************************************************

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