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Re: WG discussion: proposal to remove BP 13 - Provide subsets for large spatial datasets

From: Jeremy Tandy <jeremy.tandy@gmail.com>
Date: Thu, 02 Mar 2017 16:10:20 +0000
Message-ID: <CADtUq_3rNObAE8etBFmknaeZMXJHRz0+fffQ+azSC3Me=R8K+g@mail.gmail.com>
To: Clemens Portele <portele@interactive-instruments.de>
Cc: SDW WG Public List <public-sdw-wg@w3.org>
WRT relationship between subset and source; it would be good to include the
text from your email in the BP. Somewhere.

Thanks :)
On Thu, 2 Mar 2017 at 13:12, Clemens Portele <
portele@interactive-instruments.de> wrote:

> Hi Jeremy,
> your suggestions make sense to me, I agree with them. If we decide to
> remove BP13 I could create a PR for the changes.
> Regarding the relationship between the subset and the source, I agree that
> it would be good practice to be clear about the relationship. In HTML this
> could be descriptive text or it is implicitly clear for humans, in
> schema.org it could be http://schema.org/isPartOf (this is what we use in
> ldproxy in subsets), in RDF there is PROV-O, in 19115 there is LI_Lineage,
> etc. Arguably this should be part of DW BP 18, but since it is missing
> there we should include it, too. Paging is a very special case of a subset
> and here the previous/next links etc will provide the context, I think.
> Thanks,
> Clemens
> On 2 Mar 2017, at 13:33, Jeremy Tandy <jeremy.tandy@gmail.com> wrote:
> Clemens
> +1 from me.
> I would suggest the following changes to accommodate the removal of BP13
> ...
> Up in the ยง12.6 intro material, where you refer to DWBP's BP18, add a
> comment about why subsetting spatial data is often necessary. BP13 "why"
> already says:
> ```
> Spatial datasets, particularly coverages
> <http://w3c.github.io/sdw/bp/#dfn-coverage> such as satellite imagery,
> sensor measurement time-series and climate prediction data, are often very
> large. In these cases it is useful to provide subsets by having identifiers
> for conveniently sized subsets of large datasets that Web applications can
> work with.
> ```
> Effectively, breaking up a large coverage into pre-defined lumps that you
> can access via HTTP Get requests is a _very simple_ API!
> In the examples for SDW BP13 we refer to DataCube slices. This is already
> covered in DWBP so we can ditch that. Another of the [suggested] examples
> is "Mapping a URI template (as specified in [RFC6570
> <http://w3c.github.io/sdw/bp/#bib-RFC6570>]) to a WCS
> <http://w3c.github.io/sdw/bp/#dfn-web-coverage-service-wcs> or OPeNDAP
> <http://www.opendap.org/> service end-point". Reflecting on this, I
> wonder if this approach should be listed as a mechanism that can help to "Reuse
> your existing spatial data infrastructure" - as stated in BP11? You
> already mention "wrapper, proxy or a shim layer", but the mentioning the
> URI template would be useful. Alternatively, Example 22 (talking about the
> Environment Agency Bathing Water Quality API and the Linked Data API) might
> be a good point too; as the Linked Data API configuration uses URI
> templates to provide RESTful access to SPARQL queries thereby taking away
> from the user the challenge of writing generalised SPARQL queries and
> understanding the underpinning data model. In fact, I think it would be
> worth fleshing out this example anyway.
> (for reference, documentation on Epimorhic's implementation "ELDA" can be
> found here: http://epimorphics.github.io/elda/current/index.html)
> Finally, I wonder whether we have a gap. Currently BP13 talks about using "
> PROV-O <https://www.w3.org/TR/prov-o/> to describe the relationship
> between the subset, the original large dataset and the mechanism used to
> derive the subset". I'm not so worried about PROV-O, but I think that it
> would be worth asserting that it is useful to relate the sub-set to the
> complete resource from whence it came. Re-reading your edits to BP11, I
> think that we may have this covered where you talk about "paging" responses
> (using LDP or Hydra pagination).
> Hope that helps.
> Jeremy
> On Wed, 1 Mar 2017 at 17:41 Clemens Portele <
> portele@interactive-instruments.de> wrote:
> Hi all,
> in the BP call today [1] we discussed, if BP 13 [2] could or should be
> removed.
> The rationale would be:
> * DWBP now has BP 18 ("Provide Subsets for Large Datasets") [3] which has
> almost the same name and already covers most of the aspects. It also
> mentions the RDF Data Cube Vocabulary.
> * DW BP 18 is referenced and discussed in the introduction of section 12.6
> and in BP 11 [4].
> * Currently it feels as if there is not enough content left to keep a
> separate BP providing actionable guidance (beyond what is already in DW BP
> 18 and SDW BP 11 on that topic).
> * If content from BP13 should be kept, it could be integrated into BP 11.
> Any thoughts?
> Clemens
> [1] https://www.w3.org/2017/03/01-sdwbp-minutes.html
> [2] http://w3c.github.io/sdw/bp/#ids-for-chunks
> [3] https://www.w3.org/TR/dwbp/#ProvideSubsets
> [4] http://w3c.github.io/sdw/bp/#bp-exposing-via-api
Received on Thursday, 2 March 2017 16:33:53 UTC

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