Re: Coverage subgroup update

hm, is this aligned with the OGC coverage model? If not, why do you think that
OGC could support something not compatible?
puzzled,
Peter


On 07/19/2016 10:42 PM, Bill Roberts wrote:
> Hi all
>
> Sorry for being a bit quiet on this over the last month or so - it was as a
> result of a combination of holiday and other commitments.
>
> However, some work on the topic has been continuing.  Here is an update for
> discussion in the SDW plenary call tomorrow.
>
> In particular I had a meeting in Reading on 5 July with Jon Blower and
> fellow-editor Maik Riechert.
>
> During that we came up with a proposed approach that I would like to put to
> the group.  The essence of this is that we take the CoverageJSON specification
> of Maik and Jon and put it forward as a potential W3C/OGC recommendation.  See
> https://github.com/covjson/specification/blob/master/spec.md for the current
> status of the CoverageJSON specification.
>
> That spec is still work in progress and we identified a couple of areas where
> we know we'll want to add to it, notably around a URI convention for
> identifying an extract of a gridded coverage, including the ability to
> identify a single point within a coverage. (Some initial discussion of this
> issue at https://github.com/covjson/specification/issues/66).
>
> Maik and Jon understandably feel that it is for others to judge whether their
> work is an appropriate solution to the requirements of the SDW group.  My
> opinion from our discussions and initial review of our requirements is that it
> is indeed a good solution and I hope I can be reasonably objective about that.  
>
> My intention is to work through the requirements from the UCR again and
> systematically test and cross-reference them to parts of the CovJSON spec.
> I've set up a wiki page for that:
> https://www.w3.org/2015/spatial/wiki/Cross_reference_of_UCR_to_CovJSON_spec
>  That should give us a focus for identifying and discussing issues around the
> details of the spec and provide evidence of the suitability of the approach
> (or not, as the case may be). 
>
> There has also been substantial interest and work within the coverage
> sub-group on how to apply the RDF Data Cube vocabulary to coverage data, and
> some experiments on possible adaptations to it.  The main potential drawback
> of the RDF Data Cube approach in this context is its verbosity for large
> coverages.  My feeling is that the standard RDF Data Cube approach could be a
> good option in the subset of applications where the total data volume is not
> excessive - creating a qb:Observation and associated triples for each data
> point in a coverage.  I'd like to see us prepare a note of some sort to
> explain how that would work.  I also think it would be possible and desirable
> to document a transformation algorithm or process for converting CoverageJSON
> (with its 'abbreviated' approach to defining the domain of a coverage) to an
> RDF Data Cube representation.
>
> So the proposed outputs of the group would then be:
>
> 1) the specification of the CoverageJSON format, to become a W3 Recommendation
> (and OGC equivalent)
> 2) a Primer document to help people understand how to get started with it.
>  (Noting that Maik has already prepared some learning material at
> https://covjson.gitbooks.io/cookbook/content/)
> 3) contributions to the SDW BP relating to coverage data, to explain how
> CovJSON would be applied in relevant applications
> 4) a note on how RDF Data Cube can be used for coverages and a process for
> converting CovJSON to RDF Data Cube
>
> Naturally I expect to discuss this proposal in plenary and coverage sub-group
> calls!
>
> Best regards
>
> Bill
>
>
>
>
>
>

-- 
Dr. Peter Baumann
 - Professor of Computer Science, Jacobs University Bremen
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