Dear Ben & all,
IUB will work in field 1 below, implementing both WCS 1.1 and, based on
its coverage model, WCPS 1.0. We intend to address all items you listed
except irregular grids and maybe 2 time dimensions.
BTW, WCS 1.1 does not (yet) deal with multiple coverages, however,
response coverages can be split into multiple files (such as
mosaicking). WCPS supports n-coverage responses per request.
As a possible add-on to your list: The coverage field structure has
been defined as either atomic or an n-dimensional matrix (without any
spatial semantics. though) to allow unlimited complexity; in other
words, each pixel/voxel can be a vector/matrix/tensor itself. Requests
can slice and dice such a structure to allow what we call "range
subsetting". Exploring this concept in non-trivial use cases I figure
interesting. We will do this to some extent, but we are not the
application specialists.
cheers,
Peter
Ben Domenico wrote:
Hi,
During the last several weeks at the Unidata User Workshop, the ESIP
Federabion meeting, and at IGARSS 2006, I had the opportunity to
discuss possible objectives for the GALEON Phase 2 Interoperability
Experiment with a number of GALEON paricipants. From what I can
decipher from my cryptic notes, the goals can be divided into 3
categories:
1. Implement and test clients and servers that conform to the new WCS
1.1 spec and experiment with them on a wide range of real-world
datasets. From the GALEON perspective, some of the important changes
in WCS 1.1 are:
-- multiple coverages in one request
-- multiple fields in a coverage
-- 3 spatial dimensions
-- 2 time dimensions (e.g., the time a forecast was run and the
forecast times within the run)
-- relative time ( e.g., the latest image, the last 5 images, ...)
-- non-spatial dimension (e.g., pressure or density)
-- irregular grids
2. Catalogs and/or WCS getCapabilities lists? The getCapabilities
request appears to be inadequate to return a list of all the coverages
on a WCS server. Several people have suggested that GALEON Phase 2
include experiments that involve CS-W (Catalog Services for the Web)
as well as WCS. As an illustration of the challenge, the top level
THREDDS catalog represented in HTML at:
http://motherlode.ucar.edu:8080/thredds/catalog.html
includes several catalogs of catalogs of different types of real time
datasets. If you drill down in the "NCEP Model Data," you'll get to
collections of many datasets, each of which contains hundreds of
coverages. These catalogs are being updated in near real time as new
data arrive. Currently these datasets are catalogued using THREDDS
technology, but it would be good to have a standards-based interface
as well. Without such catalogs, the WCS interface is much less
effective.
I should add that those NCEP model output datasets also exhibit all
the characteristics suggested for interoperability testing in item 1
above so they can be used as grist for a couple major phase 2 objectives.
3. GML dialects
There appears to be an accelerating trend to develop new XML schemas
for many subdisciplines in the geosciences. Even within the world of
GML, many profiles are evolving. Within the GALEON team discussions,
at least 3 have come up in the context of methods for characterizing
CF-netCDF characteristics in a standard form:
-- ncML-GML
-- CSML
-- GMLJP2
Some effort toward testing the applicability and effectiveness of
these approaches would be valuable.
This is a pretty full agenda, but I would not expect all the
participants to work on all the items. On the other hand, it would be
usefull to have at least some effort focuse in each area.
There have also been some suggestions relating to web processing and
chaining services, but the general sense seems to be to leave that to
the OGCnetworks -- GALEON and GSN and to collaborate with the ESIP
Federation endeavors in that realm. See:
http://wiki.esipfed.org/index.php/Web_Services
I am going to send a copy of this to a few colleagues who expressed an
interest in the work but are not part of the GALEON team ... yet.
Please let us all know which (if any) aspects of the imposing list of
objectives your group would likely participate in. Comments or
corrections to any of this are welcome.
-- Ben
