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Hi Benno, You're correct, comma separated conventions can be used in the global Conventions attribute. It says this on the netCDF Conventions web page http://www.unidata.ucar.edu/software/netcdf/conventions.html which includes the following paragraph: It is possible for a netCDF file to adhere to more than one set of conventions, even when there is no inheritance relationship among the conventions. In this case, the value of the `Conventions' attribute may be a single text string containing a list of the convention names, separated by blank space or commas, such as :Conventions = "XXX, YYY" ; We need to make the User Guide documentation on Conventions match the above, if it doesn't already. I'll put that on my list. I've been following your CF proposal for name spaces and Jonathan's arguments as well. I haven't commented yet, because I don't consider myself very well informed about metadata standards. However, it seems to me that there is an issue about where the information about mappings among various metadata standards should be stored. On the one hand, you could store the fact that a particular data variable has associated metadata that conforms to standards X, Y, and Z in each data file that has such data, repeating the same information many times in many data files. Alternatively, you could store the relationships among X, Y, Z, and perhaps later W metadata conventions as they pertain to that variable in one place and have the variable metadata use indirection to point to that place. It's the old argument about redundancy versus maintainability: do you represent information in one place where it can be maintained easily but requires indirection, or in lots of places redundantly, where it is close to the data? Namespaces may offer a sort of middle road that provides short abbreviations for information uniquely defined somwhere authoritatively. But that's probably obvious and not worth saying on the CF-metadata Wiki on issue 27 ... --Russ Russ Rew UCAR Unidata Program address@hidden http://www.unidata.ucar.edu Ticket Details =================== Ticket ID: RAN-492926 Department: Support netCDF Priority: Normal Status: Closed