[CF-metadata] CF-1.6 Conformance Requirements/Recommendations

From: Jonathan Gregory <j.m.gregory>
Date: Thu, 29 Mar 2012 16:04:34 +0100

Dear all

If we say, "applications are free to assume that data is missing where the
auxiliary coordinates are missing" (John Caron's words), it means that
applications can also choose to do something else, such as trying to guess
what the location is and plotting it or doing some calculation with that
guess. As far as the data-provider is concerned, that behaviour is
unpredictable (John Graybeal's word), since different analysis software will
do different things. Some of them may be appropriate, some of them might not
be. This doesn't sound good to me, and it's why I tend to think that missing
values in aux coords should not be allowed where there is non-missing data.

To repeat, that is not an argument against storing the information in the
file, just for not for labelling it as an aux coord variable. In a second step,
the data-provider might reprocess the file and fill in the missing values. Then
it can safely be an aux coord var. It is now reliable, since the values have
been estimated by an appropriate method by the original data provider.

Best wishes

Jonathan
Received on Thu Mar 29 2012 - 09:04:34 BST