Re: Selectors as URIs?

We discussed fragments in the community group at length.

The concerns about the approach are documented here:
    http://www.w3.org/TR/annotation-model/#fragment-uris

These boil down to the fact that as you get more sophisticated selections
the URI becomes unbearably long.
Consider serializing an entire SVG document into the URI to specify a non
rectangular area. Or selecting the previous and following 1024 Gs Cs As and
Ts to select a range of text in a genetic sequence.

My personal position is that selectors should not be turned into fragments,
because (especially) that would break the rules of fragment identifiers as
laid out in RFC 3986:

The semantics of a fragment identifier are defined by the set of
representations that might result from a retrieval action on the
primary resource.

As further discussed by JeniT here:
    http://www.w3.org/TR/fragid-best-practices/

Basically, unless there's a new text/HTML RFC that allows us to do it, we
can't arbitrarily shove the description of the segment into its identity.

Rob


On Mon, Apr 13, 2015 at 9:10 AM, Ivan Herman <ivan@w3.org> wrote:

> (Although this may not be immediately relevant to the Working Group right
> now, I think the question *may* become relevant, hence my copy to it…)
>
> Rob, Paolo,
>
> a question came up at the Digital Publishing IG today. The IG is looking
> at general fragment identifiers for the purpose of identifying portions
> within a digital document (typically EPUB, but also some future versions of
> it). The Selector structure of the OA obviously gives a great model for
> various types of anchors, mainly when combined with other, existing
> fragment id definitions.
>
> However, at present, the selectors are defined in terms of RDF resources;
> to take an example from the spec, it says, for example
>
> selector": {
>       "@id": "http://example.org/selector1",
>       "@type": "oa:DataPositionSelector",
>       "start": 4096,
>       "end": 4104
> }
>
> To be usable for a fragment identification, this structure should be
> turned into some sort of a, well, URI fragment. I mean, it is probably
> relatively easy to do this, something like
>
>
> http://www.example.org/#selector(type=DataPositionSelector,start=4096,end=4104)
>
> would do it but, of course, the ideal would be if that type of fragment
> format would be defined at one place.
>
> The question is: has this ever been discussed previously on the OA model?
> If it hasn't been done, should it be done? If it should be done, should it
> be done by this WG, or some other group?
>
> Thanks
>
> Ivan
>
>
> ----
> Ivan Herman, W3C
> Digital Publishing Activity Lead
> Home: http://www.w3.org/People/Ivan/
> mobile: +31-641044153
> ORCID ID: http://orcid.org/0000-0003-0782-2704
>
>
>
>
>


-- 
Rob Sanderson
Information Standards Advocate
Digital Library Systems and Services
Stanford, CA 94305