Hi,
On Fri, 22 Oct 2010, Lowry, Roy K wrote:
> I wonder how many existing CF data files would have the meaning of their
> time channel changed were this suggestion to be adopted.
I am sure many. In some cases it might even make them accurate. :-) At some
level, it's a tradeoff between "breaking" existing data descriptions and
creating a more robust standard. Whether my suggestion creates a more
robust standard or not is up for debate. It does align it more closely with
the ISO standard, and I think there's something to be said for that.
> If I were Julia I would be reworking my data so that the time channel was
> true UT. I've had so many problems in the past with local time
> co-ordinates........
It's not data I'm generating, but rather data provided by a PI who has
determined that this is how he wants to present his data. I believe the
idea is to be able to view a wide geographic area over the same effective
local time. It's a composite image. If you can tell me how to represent
these multiple UTC times for one variable using the existing CF
conventions, then I'll try to do so. I believe CF limits me to specifying
one time zone for a particular time dimension. Re-working the data so that
it's broken up into separate time zones would, as I understand it, mean
splitting up the data variable into multiple variables, each with their own
time dimension, which is not what the data provider wants to do. Splitting
the variable would require the user to put the pieces back together in
order to see the image as the data provider intended. As far as I can tell,
following the ISO interpretation of the time zone indicator does exactly
what I need without ambiguity. I'd like to describe the data in a way
that's perfectly compliant with the CF convention, but in this case I don't
see a way to do so.
Thanks,
Julia
--
Julia Collins
National Snow and Ice Data Center
http://nsidc.org/
collinsj at nsidc.org
+1 303.492.6405
Received on Fri Oct 22 2010 - 10:32:35 BST
