Dear all I agree with Balaji about this: > It is perfectly possible to configure a GCM out of components with > inconsistent datums. ... > I still feel my principal objection to specifying the datum is the > implication of precision that does not exist. This kind of argument may apply more to models, but it appears from the comments that it might apply to obs datasets as well, for instance when they have been assembled from various sources, which could be poorly documented.
Hence in terms of John's questions, I think this is good: > 1) possible recommendations by CF to always include the datum, and > making sure we have the right metadata to do so. We could make a recommendation in the standard document to include the grid_mapping, if there is an applicable one, whenever there are horizontal coordinates. The CF checker would then produce a warning if the grid_mapping was absent. But I don't think it is the role of CF to include: > 2) possible recommendations by CF as to what to do if the datum is not > present, or is only partially specified. CF is a convention for allowing metadata to be provided. Its purpose is not to prescribe or guess what the metadata should be. There is lots of important metadata which is optional, such as standard names and bounds, and we do not recommend what should be done when they are missing. Cheers Jonathan _______________________________________________ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata