Dear all Thanks for the discussions. I think non-CF metadata in a CF file can't be expected to conform to CF principles, but that doesn't mean we shouldn't stick to our principles. I agree with Karl @taylor13 that discussion of how to identify the convention followed by particular attributes belongs in a different issue from this one. It has been raised before, in fact.
Taking up the suggestions from @sethmcg about self-describing being a guiding principle (not an absolute requirement) in (1) and Philip @cameronsmith1 about standard names in (3), here's the present proposal: (1) CF-netCDF metadata is designed to make datasets self-describing as far as practically possible. A self-describing dataset is one which can be interpreted without need for reference to resources outside itself, and the CF principle is to minimise that need. Therefore CF-netCDF does not use codes, but instead relies on controlled vocabularies containing terms that are chosen to be self-explanatory (but more detailed definitions of them are provided in CF documents). (2) The conventions are changed only as actually required by common use-cases, and not for needs which cannot be anticipated with certainty. (3) In order to keep them logical, consistent in approach and as simple as possible, the netCDF conventions are devised with and within the conceptual framework of the CF data model, and new standard names are constructed as far as possible to follow the syntax and vocabulary of existing standard names. (4) The conventions should be practicable for both producers and users of data. (5) The metadata should be both easily readable by humans and easily parsable by programs. (6) To avoid potential inconsistency within the metadata, the conventions should minimise redundancy. (7) The conventions should minimise the possibility for mistakes by data-writers and data-readers. (8) Conventions are provided to allow data-producers to describe the data they wish to produce, rather than attempting to prescribe what data they should produce; consequently most CF conventions are optional. (9) Because many datasets remain in use for a long time after production, it is desirable that metadata written according to previous versions of the convention should also be compliant with and have the same interpretation under later versions. (10) Because all previous versions must generally continue to be supported in software for the sake of archived datasets, and in order to limit the complexity of the conventions, there is a strong preference against introducing any new capability to the conventions when there is already some method that can adequately serve the same purpose (even if a different method would arguably be better than the existing one). Would you support it in this form (Seth, Karl, Philip)? Are there further concerns or additions? Best wishes Jonathan -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://github.com/cf-convention/cf-conventions/issues/273#issuecomment-656724527 This list forwards relevant notifications from Github. It is distinct from [email protected], although if you do nothing, a subscription to the UCAR list will result in a subscription to this list. To unsubscribe from this list only, send a message to [email protected].
