Hi Richard, We are considering similar questions for the OOI Cyberinfrastructure.
I am wondering why you say the history attribute is only intended to be human readable? (I'm not an expert on netCDF, so this may be a doofus question.) I couldn't find any language that says that, and some of the conventions suggest machine-readable is just fine, and I'd prefer a machine-readable history, so long as it's still human-readable. In the COARDS profile http://ferret.wrc.noaa.gov/noaa_coop/coop_cdf_profile.html it says "Although not mandatory the attribute 'history' is recommended to record the evolution of the data contained within a netCDF file. Applications which process netCDF data can append their information to the history attribute." In the netCDF Attribute Convention for Dataset Discovery, http://www.unidata.ucar.edu/software/netcdf-java/formats/DataDiscoveryAttConvention.html the history attribute is described as "Provides an audit trail for modifications to the original data." And by example, I know that MBARI has a fairly complete history that they put in NetCDF files, for example see http://dods.mbari.org/opendap/data/ssdsdata/deployments/m0/200701/OS_MBARI-M0_20070130_R_TS.nc.info and https://confluence.oceanobservatories.org/display/CIDev/Define+use+case+for+data+provenance In the sample, this history is not contained in the history attribute, but in an attribute called ssds_provenance. I don't think that example is branched, but they may have some that are, and that format looks trivial to express branches to me. (And is both readable and machine-parseable, too. Kudos to Mike McCann and the MBARI team.) If the MBARI syntax is parseable and there are not competing syntaxes, that would not be a bad proposal in my book. Since people use all sorts of things for history, we might want the first line to specify the syntax/convention being used. John On Sep 5, 2011, at 05:38, Hattersley, Richard wrote: > Dear all, > > Are there any existing practices (either established or experimental) for the > use of the "history" attribute when dealing with complex, branching > processing histories? > > Given the "history" attribute is only intended to be human readable, I > suspect the answer is "no". In which case, what would be more palatable: > inventing a new syntax, or throwing away everything prior to the last linear > sequence? > > > Richard Hattersley AVD Iris Technical Lead > Met Office FitzRoy Road Exeter Devon EX1 3PB United Kingdom > Tel: +44 (0)1392 885702 Fax: +44 (0)1392 885681 > Email: [email protected] Website: www.metoffice.gov.uk > > _______________________________________________ > CF-metadata mailing list > [email protected] > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata John Graybeal <mailto:[email protected]> phone: 858-534-2162 Product Manager Ocean Observatories Initiative Cyberinfrastructure Project: http://ci.oceanobservatories.org Marine Metadata Interoperability Project: http://marinemetadata.org _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
