Re: [wcsplus] WCS 1.0+ interoperability and application profiles

Hi Bruce (cc list),

These are important points, thanks.  I think GALEON extracted some
best-practice conventions that will probably help here.

A wider question - having missed the Boulder TC that spawned this list
and the concept of a "WCS 1.0.0+" I'd like to know how this effort is
regarded in OGC and the WCS community?  How likely is "WCS+" to be
accepted as a standard (and, more importantly, how many people are
likely to actually implement it)?  Is it likely to be superseded very
quickly by WCS1.2?  How much effort is it really worth putting in to
this?

Cheers, Jon

On 10/30/07, Wright, Bruce <bruce.wright@xxxxxxxxxxxxxxxx> wrote:



Hi All,

Sorry that it's taken me so long to start posting the wcsplus mailing list
(particularly as I was in on some of the very early discussions on WCS 1.0+)
- my (poor) excuse is a combination of holiday, incompetence (my initial
subscription to the mailing list failed) and other work commitments.

Part of those work commitment was the production of a draft interface
specification for a WCS which will be built on top of "Visual Weather" (a
software package developed by a company called IBL), which will become the
future Met Office forecaster workstation system. As this is being developed
by IBL, as an enhancement to their software, I'm afraid it will not be open
source, but the interface specification is open, and the process of drafting
this has thrown up a number of issues that I think should be of interest to
this forum.

The draft WCS interface specification that I provided to IBL was based on
WCS 1.0, as it needed to be provided now (before the WCS 1.0+ specification
has been developed), but I (like others) found that there were a number of
areas, where I had to make design decision that potentially reduce
interoperability. Where this was the case, I looked initially to follow the
approach taken for a WMS that has already been produced for Visual Weather
by IBL (to our specification), to the THREDDS WCS (which we have been doing
some evaluation work on) and to the early ideas for the WCS 1.0+ spec.

Since then, I have also had a look at some of the DEW WCS information that
Adit and Jon have posted, and what struck me is the large number of areas
where the THREDDS WCS, the DEWS WCS and the Visual Weather WCS (as I will
call it) adopt either fundamentally different approaches, or at least
different conventions. A few examples are:

- Treatment of the 3 (related) time parameters that can be used to
characterise a model forecast (i.e. Model Run ('analysis time'), validity
time and forecast period (only 2 of which are required to uniquely fix a
coverage, but which 2 are preferable depends on the client application or
user);

- Handling of coordinate reference systems (e.g. horizontal only or 3d);
- Vertical levels as part of the Domain Set (e.g. BBOX) or the Range Set (a
PARAMETER);
- PARAMETER names use to define the Range Set;
- and even, the name for a CF-compliant NetCDF3 file for the returned
format!
(and probably many more)

I feel that some elements of these can and should be tackled directly as
part of a WCS 1.0+ specification, but others should probably form part of an
application profile for the FES community.

Any thoughts on this?

I will post separately on some of the specific areas, rather than make this
posting too long.

Regards,
Bruce
--
Bruce Wright  IT Architect
Met Office  FitzRoy Road Exeter EX1 3PB United Kingdom
Tel: +44 (0)1392 886481  Fax: 0870 9005050
E-mail: bruce.wright@xxxxxxxxxxxxxxxx http://www.metoffice.gov.uk

--
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Technical Director         Tel: +44 118 378 8741 (ESSC)
Reading e-Science Centre   Fax: +44 118 378 6413
ESSC                       Email: jdb@xxxxxxxxxxxxxxxxxxxx
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