Hi Nan, > I'm certain that this has been discussed, but I can't > find it anywhere in the email archive, or on the trac site. > > Don't we allow a compound (comma separated) string > in the global attribute 'Conventions'? > > Because there are new, complimentary conventions > available - like the ACDD (discovery attributes) - it would > be very handy to allow multiple conventions to be specified > in a single attribute: "CF-1.6, ACDD, OceanSITESv2.1.2".
The recommendation on the Unidata site for multiple conventions http://www.unidata.ucar.edu/netcdf/conventions.html is to use spaces rather than commas: 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 (recommended) or commas (if a convention name contains blanks), for example :Conventions = "XXX YYY" ; > Here's the text from the current version of the cf-conventions > document: > > > 2.6.1. Identification of Conventions > > We recommend that netCDF files > > that follow these > conventions > indicate this by setting the NUG defined global attribute > Conventions > to the string > value "CF-1.6". The string is interpreted as a > directory name relative to a > directory that is a > repository of > documents describing sets of discipline-specific conventions. > > I'm not sure about the use of the directory structure in the > quoted section of the standard; is that actually used by a > lot of software? Would a separate attribute providing the > URL for the convention be more flexible/useful? We agree and Unidata Conventions web page recommends what you have described: ... Originally, these conventions were named by a string that was interpreted as a directory name relative to the directory /pub/netcdf/Conventions/ on the host ftp.unidata.ucar.edu. This web page is now the preferred and authoritative location for registering a URI reference to a set of conventions maintained elsewhere. The FTP site will be preserved for compatibility with existing references, but authors of new conventions should submit a request to [email protected] for listing on this page. --Russ _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
