[CF-metadata] Question on WKT representation of CRS (Bentley, Philip)

From: Wright, Bruce <bruce.wright>
Date: Wed, 5 Oct 2011 17:42:20 +0100

Hi Bryan,

I suspect it probably is becoming important for weather forecast output
now.

At the Met Office, we're now generating 2km post-processed forecast data
(from models running at up 1.5km resolution). At present, this is mainly
shared internally (and with a small number of 'expert' customers) using
bespoke data formats (which don't fully describe the CRS) . However, in
future I'd expect to be sharing these data more widely, ideally using
CF-netCDF (and GRIB2), and would feel more comfortable, it we could
fully characterise CRS in use, to ensure appropriate use in combination
with other data.

But to echo your last comment, a CRS WKT enhancement should be optional,
and not replace the current CF grid description information - we don't
want to break existing client software, just allow a fuller description
of the CRS where required.

Regards,
Bruce

-- 
Bruce Wright  Expert IT Analyst (Data Management)
Met Office FitzRoy Road Exeter EX1 3PB United Kingdom 
Tel: +44 (0)1392 886481 Fax: +44 (0)1392 885681
E-mail: bruce.wright at metoffice.gov.uk http://www.metoffice.gov.uk 
-----Original Message-----
From: cf-metadata-bounces at cgd.ucar.edu
[mailto:cf-metadata-bounces at cgd.ucar.edu] On Behalf Of Bryan Lawrence
Sent: 05 October 2011 12:52
To: cf-metadata at cgd.ucar.edu
Subject: Re: [CF-metadata] Question on WKT representation of CRS
(Bentley,Philip)
Hi Seth
I haven't read all  the threads ... but I strongly agree with your last
paragraph!  
I have had many conversations with folks who think that adding datums
will make data more usable to the impacts community, where datum errors
can move things by o(10)s of km ... and my protestation that no one
should interpret as physical any differences on those scales from a
(climate) model (even one run at o(km) resolution if such exists) ...
was simply ignored. The reality is exactly what you say, that level of
specificity is simply inappropriate.
I appreciate some of the arguments raised in the thread on storing
lat/lon coordinates, about the need for the use of one in a GIS workflow
- but frankly I think that's an issue about workflow metadata not source
data metadata.  As Balaji and others said, there might not even be *one*
datum appropriate for GCM work ...
Of course observational data may well be different,  and I'm not sure
about NWP ... especially mesoscale models. So by all means, facilitate
the provision of this information, but don't make it compulsory ... and
I think it would be with WKT?
Cheers
Bryan

Received on Wed Oct 05 2011 - 10:42:20 BST