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Hello again, It has been pointed out that my earlier note (included below) can be interpreted as a criticism of WCS for not being capable of dealing with the various categories of observational data collections we deal with in the GALEON community. That was not my intention. In fact, I believe the first order of business is for the GALEON/CF/netCDF community is to come to agreement on extensions to the CF conventions that apply to collections of observational data. John Caron has proposed a set of such extensions. In parallel, we need to work with various OGC groups to determine how best to convey those types of data. For my part, I plan to continue working with the WCS Standards Working Group on a set of use cases that capture the requirements of the GALEON community for serving and accessing these observational data collections. The leadership of the WCS SWG has made it clear that they welcome and anxiously await this sort of input from GALEON. In American sports jargon, the ball is in GALEON's court. My apologies for any misunderstandings my earlier note caused. -- Ben On Wed, Dec 10, 2008 at 4:07 AM, Ben Domenico <Ben@xxxxxxxxxxxxxxxx> wrote:
Hi Steven et al., Following up on an action item for me at the Coverages session at the Valencia Technical Committee meetings, I'd like to mention two GALEON-related items. First, we are working on a WCS extension for CF-netCDF encoding. The GALEON group made a a few valuable suggestion for augmenting the draft. encoding spec that was circulated by Stefano Nativi to the GALEON email list. Those changes are being incorporated into the next draft that will be submitted to the SWG. It also seems the draft should be recast in terms of the encoding extensions template that is being developed. Second, the topic of non-gridded coverages came up at both the joint session with SWE and the Coverages session at the TC meetings. In GALEON, the issue of how to deliver non-gridded observational data is an important question. The relationship to WCS is not entirely clear, but GALEON 1 showed the value of a simple WCS use case in which the client defines a 3D bounding box, a time frame, and a property (temperature, pressure, etc.) and gets back a coverage encoded in CF-netCDF. However, with WCS we are currently constrained to coverages that are gridded at regularly spaced points in some Coordinate Reference System. In the GALEON community, this works for some forecast model output and some geostationary satellite imagery. A key question facing GALEON now is how to deliver the wide variety of collections of observational data via a similarly straightforward request -- based on OGC and ISO standards. And specifically, might WCS evolve (perhaps via extensions to the core) so that it would a viable protocol? For the true gluttons for punishment among you, I'm attempting to capture some of these issues related to the collections of non-gridded data in an airport weather use case at: http://sites.google.com/site/galeonteam/airport-weather-use-case-and-standards As you will note, this is a very rough compilation drawn from presentations by several GALEON team members. Many standard specifications come into play -- WCS possibly among them. As time permits, I plan to refine this document into something more complete and coherent, but I think it captures the salient issues even in its current form. -- Ben
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