Dear Martin and Karl Actually I think the way it's done in CMIP5 is consistent with the convention. It is correct that region is the standard name for a string-valued variable, and flag_values and flag_meanings supply a method to encode the strings as numbers. This is very much like Example 3.3 in Section 3.5, where string-valued status flags are encoded as numbers. On this email list we have advised people from time to time to use flag_values and flag_meanings in this way to encode strings as numbers.
You could argue that it is a bit different in principle. The intention of Sect 3.5 is to supply a way to decode numbers in a data variable into strings. That is arguably not identical with an intention of providing a way to encode strings as numbers in a data variable, but since the process is reversible the mechanism works both ways! If you think that this use of the convention is not obvious as it stands, then I would propose that we insert an extra sentence in Sect 3.5 pointing out the use of this mechanism to encode strings. We could include the CMIP5 basins as an example of it. Best wishes Jonathan ----- Forwarded message from Karl Taylor <[email protected]> ----- > Date: Fri, 20 May 2016 15:16:23 -0700 > From: Karl Taylor <[email protected]> > To: [email protected] > Subject: Re: [CF-metadata] Use of CF standard name region > User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:38.0) > Gecko/20100101 Thunderbird/38.7.2 > > Hi all, > > Perhaps we should define a new standard_name: e.g., basin_index (or > region_index) to replace the misused "region" standard_name. > > I would note that in the conventions document in example 3.3 there > is a standard name: "sea_water_speed status_flag" > > "status_flag" is a standard "name modifier" (see appendix C). > > So, if we want to modify the convention, we could define a new name > modifier (say "index") and explicitly indicate that flag_values can > be used as indexes (when they are integers). > > regards, > Karl > > > On 5/20/16 12:44 PM, [email protected] wrote: > >Hello All, > > > >In CMIP5 the variable "basin" was used as a fixed spatial field with integer > >values and the CF Standard Name "region", which has the definition "A > >variable with the standard name of region contains strings which indicate > >geographical regions. These strings must be chosen from the standard region > >list." > > > >The integer valued CMIP5 variable is clearly not consistent with this > >definition. The CMIP5 variable was defined with flag_values and > >flag_meanings, such that the flag_meanings were from the CF standard region > >list. > > > >The question is, should we redefine the CMIP5 variable somehow, or would it > >be acceptable to adjust the CF Standard Name definition for region to accept > >this usage which appears clear enough and is presumably much easier for > >plotting packages to handle than a spatial array of string values, > > > >regards, > >Martin > > > > > >_______________________________________________ > >CF-metadata mailing list > >[email protected] > >http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata > > _______________________________________________ > CF-metadata mailing list > [email protected] > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata ----- End forwarded message ----- _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
