Dear Charlie Thank you for your interesting post and the discussion.
As a data analyst, I have a different view from NASA. I dislike hierarchies and directories. I prefer things to be as flat as possible, with each item thoroughly described by its own independent metadata, using tools to identify what I need efficiently by use of that metadata. The reason I prefer that is because hierarchies are restrictive. They impose a particular organisation and compartmentalisation on the data, which may be an obstacle for some purposes. I think directory structures should only be used when it becomes intolerably inefficient to keep everything in one directory. Until you reach that point, clever searching algorithms can make a single flat structure seem to have whatever organisation you want for the purpose you have in hand. > But IMHO the best reason to make "group-aware" CF is to facilitate > more commonsense storage of intrinsically hierarchical datasets, e.g., > CMIP5 scenario->model->ensemble = RCP850->CESM->Historical. > Why flatten that? Because its hierarchy is a nuisance. It makes it easier to compare different ensemble members of the same experiment and model, but harder to compare the first ensemble member of the same experiment with different models, or the first ensemble member of different experiments with the same model, which are equally or more frequent needs with CMIP5 analysis. This is an example where the organisation of the data is an obstacle to its use. When I download the CMIP5 files, I put them in all in one enormous directory, and grep it to find the ones I need. That works fast enough. However, hierarchies are a fact of life, and some people like them. :-) I am probably just a bit weird. So CF has to be able to deal with groups. It does seem to go against the general tendency in CF, however, which in my opinion has been that fields should be self-describing, and their organisation into files should be as unimportant as possible. Groups tend to make files more important again. Best wishes Jonathan _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
