⇐ ⇒

[CF-metadata] Is there a convention defining day offsets to use for monthly average time series?

From: Bert Jagers <bert.jagers>
Date: Tue, 16 Aug 2011 15:46:30 +0200

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
> CF-metadata at cgd.ucar.edu
> 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.
Received on Tue Aug 16 2011 - 07:46:30 BST

This archive was generated by hypermail 2.3.0 : Tue Sep 13 2022 - 23:02:41 BST

⇐ ⇒