On Fri, Jan 11, 2013 at 9:00 AM, Aleksandar Jelenak - NOAA Affiliate
<aleksandar.jelenak at noaa.gov> wrote:
> Here's the modified proposal for the datetime_iso8601 standard name:
...
> String representing date-time information according to the ISO
> 8601:2004(E) standard.
I think we should NOT adopt a string option for datetime variables.
To quote Jonathan Gregory:
"""
In CF we have always applied the
principle that we only add to CF when there is a need to do so, i.e. there is
a use-case for something which cannot already be represented in CF
"""
We already have a way to encode datetimes in CF-netcdf.
I believe this proposal resulted from the discussion about adding a
more flexible approach to datetimes in the CF Data Model. I think
that's a good idea, but separate from what encoding is used in
CF-netcdf. ( see my recent note for more detail about the difference
between and encoding and a data model ).
1) Having multiple ways to encode the same data in file format adds
complication to all client code -- client code would need a way to
process both ISO strings and "time_unit since datetime"
2) Any client code that can process ISO strings is likely to need to
convert them to a client-specific datetime representation anyway, in
order to plot, calculate with, etc them.
3) Any client library that can process ISO strings is very likely to
be able to also work with "time_unit since datetime" encoded data
anyway -- and it had better, as that encoding is part of the standard
anyway.
As a result, we would be complicating client code, and getting no new
functionality.
The one advantage I can see at the moment is that simple, non-CF-aware
clients, like ncdump, could easily present a nice human-readable
format. But I don't think that is worth the additional complication.
-Chris
--
Christopher Barker, Ph.D.
Oceanographer
Emergency Response Division
NOAA/NOS/OR&R (206) 526-6959 voice
7600 Sand Point Way NE (206) 526-6329 fax
Seattle, WA 98115 (206) 526-6317 main reception
Chris.Barker at noaa.gov
Received on Fri Jan 11 2013 - 14:37:23 GMT
