Dear Jonathan,
Thank you; it's clear to me. Thank you for the nuance with respect to 1D
lat/lon coordinates, I'm so used to coordinates that aren't linear in
any projection that I'm always specifying full data and meta data for
all spatial coordinates.
Best regards,
Bert
-------
Jonathan Gregory wrote:
Dear Bert
In your example:
varN:coordinates = "lat lon";
varN:cell_methods = "lat: point lon: point";
if lat and lon are 1D coord vars, they aren't usually listed as coordinates
(though it is not an error to do so). CF relies on the Unidata convention of
associating 1D coords with data vars through the equality of dimension and
coord var name.
If any one of the variables refers
to 'lat'/'lon' by means of a cell method other than 'point', e.g.
'mean', then it must be specified what range/cell the cell_method
relates to i.e. 'bounds' should be required. That seems more like a
consistency *requirement* than merely a recommendation.
Yes, that is the current recommendation. We could promote it to a requirement
for the case where cell_methods is specified, I think, since both cell_methods
and bounds are CF metadata.
If 'cell_methods' is not specified on one or more variables, then the
need for 'bounds' becomes more fuzzy. The discussion on the default
interpretation for 'cell_methods' in Section 7.3 suggests that one
might distinguish between extensive quantities like
'cloud_area_fraction' and intensive quantities like
'sea_surface_height'. The former might require it, whereas it would
be optional in the latter case.
That's right. We decided to recommend that cell_methods always be included
because it's hard to make the distinction intensive/extensive.
I would agree with a general recommendation to
include 'bounds' when 'cell_methods' is missing on one or more
variables.
I think that's a good idea. I would support it. That goes beyond what we
currently have, and would require at least a "defect" ticket, perhaps a
substantive change. It would be a helpful change, to encourage data-writers
to describe their data better by including cell_methods and bounds.
Best wishes
Jonathan
_______________________________________________
CF-metadata mailing list
[email protected]
http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
DISCLAIMER: This message is intended exclusively for the addressee(s) and may
contain confidential and privileged information. If you are not the intended
recipient please notify the sender immediately and destroy this message.
Unauthorized use, disclosure or copying of this message is strictly prohibited.
The foundation 'Stichting Deltares', which has its seat at Delft, The
Netherlands, Commercial Registration Number 41146461, is not liable in any way
whatsoever for consequences and/or damages resulting from the improper,
incomplete and untimely dispatch, receipt and/or content of this e-mail.
_______________________________________________
CF-metadata mailing list
[email protected]
http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
