Re: GALEON IE Phase 2 Objectives

• To: Ben@xxxxxxxxxxxxxxxx, "Unidata GALEON" <galeon@xxxxxxxxxxxxxxxx>
• Subject: Re: GALEON IE Phase 2 Objectives
• From: stefano nativi <nativi@xxxxxxxxxxx>
• Date: Thu, 10 Aug 2006 15:03:15 +0200

Hi,

---Stefano

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>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>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

• References:
  • GALEON IE Phase 2 Objectives
    • From: Ben Domenico