I've added dods-tech to this thread. Dods-techers, we are discussing
recommendation of a metadata standard to facilitate use of OPeNDAP
accessible data in the Earth Sciences. One starting point might be to
recommend the use of CF or COARDS. Any thoughts on this?
On Aug 16, 2005, at 10:55 PM, Tennessee Leeuwenburg wrote:
Just some off-the-cuff responses.
The GODAE project is worth looking into here -- they have adopted
OpenDAP and CF. I don't know how much activity the project has.
A fair amount I think, especially the Europeans. Much of their model
data is accessible via OPeNDAP, but you are probably more on top of
this than I am.
There seems to be a difference between USGODAE and the vanilla
flavour. At any rate, they don't seem to have published anything of
significant for a couple of years, but the project is a really nice
idea.
Here in the Bureau, we have a moderate degree of standardisaton on
COARDS, but it's not an absolute rule.
The "easiest" way might be to support some particular convention in
the output, with the server being able to convert to that from a
number of different input conventions. For example, write code that
will take either a COARDS or CF input file, and do the relevant
modifications to the semantic-structure to present consistent output.
Yes. This would be quite straightforward as long as the metadata is
there in the first place to say how the data are ordered.
That at least would greatly simplify the task of visualisation (for
example).
So, I take from this that you think it would make things a lot easier
if the data were in the same semantic structure?
If coupled with a good generic data viewer (like IDV), then people
would me even more inclined to adopt the standard.
Here at the Bureau the biggest obstacle is the lack of a BUFR
interpreter for OpenDAP / thredds. This is a big deal for us, and
we're going to have to go with a hybrid solution instead of using
OpenDAP across the board. BUFR is an acronym for Binary Universal File
Representation, and has been adopted by the World Met Organisation as
a standard for obvervational data. It's a complete hassle to deal
with, because the level of software support is low.
The GDS provides some support for BUFR -
http://grads.iges.org/grads/gds/gds.html. Have you looked at that?
Peter
The other thing I thought would be cool (while we're throwing ideas
around like popcorn) would be if Thredds was also a web service, with
a WSDL and so forth.
p.s. We are working toward an XML version of OPeNDAP - the dds and das
- with the eventual idea of providing access via a web service.
Do any such conventions exist for OpenDAP?
No. The idea is to let different disciplines impose whatever
structure they want on top of OPeNDAP. The more appropriate question
would be "Does the oceanographic (or the Earth Science) community
have any such convention?" Unfortunately, the answer is again no.
That is my fault. I should have recommended one a long time ago. I
think that COARDS (or CF) would be an excellent starting point and
COARDS is becoming a de facto standard in that many data providers
use it. I was reluctant to impose COARDS on the oceanographic use of
the system since that would mean the reordering of some archives
which could be very costly. I prefer a modified C
COARDS, one that does not adhere to the semantic structure, but does
adhere to the rest of the standard.
Here at BOM we more or less have our conventions agreed on for my
particular project, but if there were any recommended best practise
it could be interesting.
What do you think of adopting COARDS or CF? Would one or the other
address all of your data sets? If not, what is missing? If it could,
but your would rather not adopt it, it would really be useful to know
why and to know what you guys have adopted and why. I am hoping that
the Marine Metadata effort comes up with a recommendation for the
oceanographic community. I'm not sure what is being done for the
meteorological community, but it would be great if there was a
similar effort (to the Marine Metadata program) and if they came up
with a recommendation.
Peter
Cheers,
-Tennessee
--
Peter Cornillon
Graduate School of Oceanography - Telephone: (401) 874-6283
University of Rhode Island - Fax:
(401) 874-6728
Narragansett, RI 02882 - E-mail:
pcornillon@xxxxxxxxxxx
--
Peter Cornillon
Graduate School of Oceanography - Telephone: (401) 874-6283
University of Rhode Island - Fax:
(401) 874-6728
Narragansett, RI 02882 - E-mail:
pcornillon@xxxxxxxxxxx
