Hi All,
I've noticed some ambiguity in the CF document around the use of the
"cf_role" attribute which I think needs clarification.
In Appendix A it states that the *cf_role* attribute is valid for use on
a coordinate variable only, however, in virtually, if not all, the
examples in Appendix H cf_role is not attached to a coordinate variable.
E.g. H.2
dimensions:
? station = 10 ; ?// measurement locations
? time = UNLIMITED ;
variables:
? float humidity(station,time) ;
? ? humidity:standard_name = "specific humidity" ;
? ? humidity:coordinates = "lat lon alt" ;
? double time(time) ;
? ? time:standard_name = "time";
? ? time:long_name = "time of measurement" ;
? ? time:units = "days since 1970-01-01 00:00:00" ;
? float lon(station) ;
? ? lon:standard_name = "longitude";
? ? lon:long_name = "station longitude";
? ? lon:units = "degrees_east";
? float lat(station) ;
? ? lat:standard_name = "latitude";
? ? lat:long_name = "station latitude" ;
? ? lat:units = "degrees_north" ;
? float alt(station) ;
? ? alt:long_name = "vertical distance above the surface" ;
? ? alt:standard_name = "height" ;
? ? alt:units = "m";
? ? alt:positive = "up";
? ? alt:axis = "Z";
? char station_name(station, name_strlen) ;
? ? station_name:long_name = "station name" ;
? ? station_name:cf_role = "timeseries_id";
attributes:
? ? :featureType = "timeSeries";
I think the cf_role variable "station_name" should be named by the
coordinates attribute for humidity.
Moreover, section 9.5 in the conventions document, 2nd paragraph, it
should say "Where feasible a coordinate or auxiliary coordinate variable
with the attribute cf_role should be included."
Assuming there are no objections I'll raise a defect ticket when Trac is
back.
Regards,
Ros.
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Received on Thu Jul 19 2018 - 07:37:26 BST
