Dear Upendra add_offset is included in CF for data variables, but not coordinate variables. Its intention is to help with packing data (CF section 8.1).
For time coordinate variables, however, an offset can effectively be included in the units, which have the form "UNITS since TIME". You can specify any reference TIME you like. Why would you like an offset for X and Y coordinates? Best wishes Jonathan _______________________________________________ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata