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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 markh): Replying to [comment:89 taylor13]: > Hi all, > > Just to note one use case (CMIP5 specifications) where, perhaps mistakenly, it was assumed that attributes appearing both as global and (with different text) as variable would be concatenated to provide more complete information. The assumption wasn't that if the variable attribute was present it would supersede/override the global one. Note that the description below distinguishes between types of information that might appear in comment and history attributes which would be common among variables vs. different from one variable to the next. For what it is worth, I took a similar interpretation to the CMIP5 guidance. I interpreted 'takes [http://dictionary.cambridge.org/dictionary/british/precedence?q=precedence precedence]' to mean that the data variable attribute was to be treated as having primacy, having more import than the global variable attribute. This is different from saying that the global attribute in this case: has no meaning / is overridden / is ignored, if a data variable has an variable attribute with the same name. I think it is useful to work with CF data variables as independent entities, so I think we should look to apply file global attributes to data variables. I think there is some semantic content is the information encoding approach in numerous cases so I think there is value in having two attribute containers, perhaps 'data_attrs' and 'inherited_attrs' so that we can preserve the source of these attributes and provide a mechanism for controlling how NetCDF files are written from Field instances. They are all attributes on the Field, in this view, there just happen to be two types This doesn't have to impact on most uses, at the top level the Field has attributes. I would add that this applies to all attributes, ones recognised by CF and ones outside of the CF conventions. This meets the use case of reproducing files, which I think is a valuable capability that many user expect and enables precedence to be applied without deleting potentially informative metadata. -- Ticket URL: <https://cf-pcmdi.llnl.gov/trac/ticket/95#comment:90> 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.
