Re: [linking-data] What should I link to? (or link between)

2015-09-29 10:30 GMT+02:00 Peter Baumann <p.baumann@jacobs-university.de>:

> Hi Jon,
>
> actually, identification and access are just two sides of the same coin.
> The request uniquely identifies the resource and sub-resource desired.
>
> You can see a GetCoverage request as one node utilizing sort of a
> (standardized) microsyntax if you will, or it can be broken down into
> several RDF elements - that's still independent.
>
> BTW, this does not preclude identifiers for subsets. But if an identifier
> really is not supposed to carry any semantics inside then we're done: it is
> just an ID. However, this doesn't say how to _get_ the actual subset
> identified, ie: there is no way of resolution. If you want that, you are
> going to have semantics in the URI, and we are back with an RDF submodel or
> microsyntax.
>

Can't a HTTP(S) URI be regarded as both an identifier and a key? Because it
is HTTP, one could try interaction using HTTP methods. To get the subset,
the GET method can be used. The response that can be expected is data
describing the subset, which could include various options for downloading
the data.

In other words, we could assume that identifiers (HTTP URIs) can be
resolved to arrive at semantics.

Regards,
Frans


>
> cheers,
> Peter
>
>
> On 2015-09-29 10:01, Jon Blower wrote:
>
> Hi Peter,
>
> Yes, of course, WCS can *access* subsets of a coverage (so can other
> protocols like OPeNDAP) but I think we need a protocol-independent way to
> *identify* the subsets.
>
> I’m picturing an RDF fragment that encodes things like the band/variable,
> spatiotemporal (or index) coordinates, and anything else. Given that URIs
> are supposed to be opaque (i.e. we’re not supposed to encode semantics in
> the URL), I think we have to define URIs that point to subset definitions.
>
> Clearly any mechanism needs to be compatible with the data models of WCS
> (and CIS), but I don’t think we should just adopt the WCS GetCoverage URL
> as the identifier for subsets.
>
> Cheers,
> Jon
>
> On 29 Sep 2015, at 09:32, Peter Baumann <p.baumann@jacobs-university.de>
> wrote:
>
> that's what we typically do with a GetCoverage request as a URL, it allows
> for trimming and slicing a coverage (down to single pixels). Beyond that,
> you can link to single bands, representations of the coverage in other
> CRSs, scaled versions, etc. And it's standard by OGC and soon INSPIRE and
> ISO.
> -Peter
>
> On 2015-09-29 03:04, Simon.Cox@csiro.au wrote:
>
> Ø  probably don’t want to link between individual pixels in a satellite
> image?
>
>
>
> Not always, but sometimes. It always seemed to me that a key requirement
> for joining gridded data and linked data was to have a URI for a subsets,
> perhaps even down to a single pixel. Does QB help here?
>
>
>
> Simon
>
>
>
> *From:* Jon Blower [mailto:j.d.blower@reading.ac.uk
> <j.d.blower@reading.ac.uk>]
> *Sent:* Tuesday, 29 September 2015 7:13 AM
> *To:* Jeremy Tandy <jeremy.tandy@gmail.com> <jeremy.tandy@gmail.com>
> *Cc:* SDW WG Public List <public-sdw-wg@w3.org> <public-sdw-wg@w3.org>
> *Subject:* Re: [linking-data] What should I link to? (or link between)
>
>
>
> Is this a question about granularity? E.g. we definitely want to link
> between datasets, but probably don’t want to link between individual pixels
> in a satellite image?
>
>
>
> One use case we are seeing in MELODIES a lot is that we want to link to
> *features* that we extract from images, but probably not the raster data
> itself.
>
>
>
> Cheers,
>
> Jon
>
>
>
>
>
> On 24 Sep 2015, at 09:30, Jeremy Tandy <jeremy.tandy@gmail.com> wrote:
>
>
>
> Email thread for collecting discussion on the question: "What should I
> link to? (or between)"
>
>
>
> The related wiki entry for this questions is here [1]
>
>
>
> For instructions about how to engage with this discussion, please see my
> previous email [2].
>
>
>
> Many thanks. Jeremy
>
>
>
> [1]:
> https://www.w3.org/2015/spatial/wiki/Linking_Data#What_should_I_link_to.3F_.28or_link_between.29
>
> [2]: https://lists.w3.org/Archives/Public/public-sdw-wg/2015Sep/0044.html
>
>
>
>
>
>
> --
> Dr. Peter Baumann
>  - Professor of Computer Science, Jacobs University Bremen
>    www.faculty.jacobs-university.de/pbaumann
>    mail: p.baumann@jacobs-university.de
>    tel: +49-421-200-3178, fax: +49-421-200-493178
>  - Executive Director, rasdaman GmbH Bremen (HRB 26793)
>    www.rasdaman.com, mail: baumann@rasdaman.com
>    tel: 0800-rasdaman, fax: 0800-rasdafax, mobile: +49-173-5837882
> "Si forte in alienas manus oberraverit hec peregrina epistola incertis ventis dimissa, sed Deo commendata, precamur ut ei reddatur cui soli destinata, nec preripiat quisquam non sibi parata." (mail disclaimer, AD 1083)
>
>
>
>
>
> --
> Dr. Peter Baumann
>  - Professor of Computer Science, Jacobs University Bremen
>    www.faculty.jacobs-university.de/pbaumann
>    mail: p.baumann@jacobs-university.de
>    tel: +49-421-200-3178, fax: +49-421-200-493178
>  - Executive Director, rasdaman GmbH Bremen (HRB 26793)
>    www.rasdaman.com, mail: baumann@rasdaman.com
>    tel: 0800-rasdaman, fax: 0800-rasdafax, mobile: +49-173-5837882
> "Si forte in alienas manus oberraverit hec peregrina epistola incertis ventis dimissa, sed Deo commendata, precamur ut ei reddatur cui soli destinata, nec preripiat quisquam non sibi parata." (mail disclaimer, AD 1083)
>
>
>
>