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#95: Development of CF 1.5 Data Model -----------------------------+---------------------------------------------- Reporter: markh | Owner: [email protected] Type: task | Status: new Priority: medium | Milestone: Component: cf-conventions | Version: Resolution: | Keywords: -----------------------------+---------------------------------------------- Comment (by bnl): Replying to [comment:76 bjlittle]: > Replying to [comment:70 davidhassell]: > > Hi David, > > Okay I'm jumping into this conversation somewhat cold, so apologies if I'm covering a previously discussed point. Hi Bill. I jumped in a few comments back. It's the done thing :-) > I'm curious about your statement with regards to global/data attributes: > > > I also think that it's not the preserve of the data model to ensure that a CF-netCDF dataset written out is identical to one read in. So long as the logical content of the input and output datasets is the same then the data model has done its job, regardless, in fact, of the formats of the two datasets. As Bryan says, software built on the CF data model will make decisions on how to format its output within the confines of creating a CF compliant file. > > I know that we're discussing the data model here and not implementation specifics, but I believe that proposing a CF data model that can only promise similar logical content will cause big issues for many data users. I've seen many, many real world CF NetCDF files where (misguided or not) a user expects the global attributes to be preserved through the load- process-save cycle. > > My concern is that if the community agree on a data model that only guarentees similar logical content, then there will be a real world impact as a concequence. Such a decision should be made explicit, at the very least, as it will be contrary to the current expectation some data users may have. The problem is that other data users have different expectations, and some of us think that the "file as a bucket" metaphor is holding us back. In particular, what do we do with (original) global file attributes by the time the variable is some way down any kind of reasonable workflow where we are accumulating provenance. They're just (logically) variable attributes because we have different assemblages of variables by then ... ... which is to say that I have never expected global file attributes to propagate *as global file attributes* through my workflow, as attributes, yes. So, I agree, let's make it explicit. The lack of explicitness is what has caused this thread :-) > > I hope that this point isn't too inappropriate given the current discussion. > > Best regards, > Bill -- Ticket URL: <https://cf-pcmdi.llnl.gov/trac/ticket/95#comment:77> CF Metadata <http://cf-pcmdi.llnl.gov/> CF Metadata This message came from the CF Trac system. To unsubscribe, without unsubscribing to the regular cf-metadata list, send a message to "[email protected]" with "unsubscribe cf-metadata" in the body of your message.
