Hi all,
Even if the missing aux coordinate values never will be found, I think
there is legitimate uses of data where some of the aux coordinate values
are missing where data values exist. For example if you want to compute
the average of data variables, you do not need the aux coordinate variable.
A netCDF-file could be used in several ways:
- Making a plot where only the values corresponding to non-missing aux
coordinates are used
- Computing the average
Therefore, I think we should allow missing values in aux coordinate
values, and also point out that the data values may be useful even if no
corresponding aux coordinates exist.
Best regards,
Egil Støren
On 03/29/2012 05:04 PM, Jonathan Gregory wrote:
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
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