Jim, I'm hoping more data providers follow your approach, as it will gradually bring along software developers, other data providers, and ultimately conventions authors. I gave a talk <http://www.unidata.ucar.edu/presentations/Rew/agu_2010_nc4_Rew.pdf> at AGU a few years back about how to manage the transition to the netCDF-4 enhanced data model. The obstacles to the transition are summarized in slides 19-21, where my lack of artistic talent is demonstrated in an illustration of the "chicken and egg logjam".
--Russ On Wed, Sep 10, 2014 at 9:25 AM, Jim Biard <[email protected]> wrote: > Tim, > > You can use netCDF-4 without "classic" format, but for true, full CF > compliance you can't use any new features. > > Personal opinion alert!!! The following is just my personal opinion. I'm > not trying to stir up trouble. I'm just sharing my observations on my > experiences. Please don't hate me. > > The official CF community position is that for backwards-compatibility > reasons, they would rather not adopt new features unless there is no "good" > workaround using the old feature set. Contention can arise over the > question of whether you view the workaround as "good" or not, but that > seems to be roughly how the thought goes. The CF community also do not view > themselves as developers of new features that aren't driven by present > needs. They are also interested in maximizing the ability of (sometimes > theoretical) existing CF-aware analysis packages to properly handle all > CF-compliant files. > > In previous conversations I've been given to understand that the effective > process for bringing new netCDF features into CF will be for someone to use > them in a dataset, doing their best to interpret CF in the light of the new > features. If it is a popular dataset, it will push the CF community towards > adopting some form of those new features. > > In a case where I was developing a new dataset that would have been > particularly unwieldy (in my opinion) without groups, I went ahead and used > them, applying a hierarchical scope approach to file and group attributes. > As my dataset is not likely to be widely used by any analysis packages, it > will not likely cause anyone grief or drive the adoption of new netCDF > features into CF. > > Grace and peace, > > Jim > > > On 9/10/14, 9:53 AM, Timothy Patterson wrote: > > Is it correct to say that, although they don't explicitly state it, the CF > conventions (1.6 and the draft 1.7) restrict compliant netCDF products to be > either netCDF-3 or netCDF-4 in classic format? There are no conventions for > the enhanced features such as groups and user-defined types like enumerated > variables, and Section 2.2, as an example, bars the use of unsigned integer > variables or string variables (which are even stated not to exist, again > implying classic-model only). > > There are some features of the enhanced model we want to use for our future > datasets (such as groups) and some features which would make life easier but > could be worked around if it led to CF compliance (enumerated types, unsigned > integers, string types, etc.). Are there any plans to introduce conventions > for the use of these enhanced features at some point in the future or would > non-classic model datasets always be seen as non-compliant? > > Thanks for your insights on this issue! > > Regards, > > Tim Patterson > > > > --------------------- > > Dr. Timothy Patterson > Instrument Data Simulation > Product Format Specification > > EUMETSAT, Eumetsatallee 1, D-64295 Darmstadt, Germany > _______________________________________________ > CF-metadata mailing > [email protected]http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata > > > -- > [image: CICS-NC] <http://www.cicsnc.org/> Visit us on > Facebook <http://www.facebook.com/cicsnc> *Jim Biard* > *Research Scholar* > Cooperative Institute for Climate and Satellites NC <http://cicsnc.org/> > North Carolina State University <http://ncsu.edu/> > NOAA's National Climatic Data Center <http://ncdc.noaa.gov/> > 151 Patton Ave, Asheville, NC 28801 > e: [email protected] > o: +1 828 271 4900 > > > > > _______________________________________________ > CF-metadata mailing list > [email protected] > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata > >
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