RE: Issue-10 unresolved in meeting today

+1 from me, too, also to http URIs

/Lars

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> -----Original Message-----
> From: Andrea Perego [mailto:andrea.perego@jrc.ec.europa.eu]
> Sent: Thursday, June 25, 2015 9:58 AM
> To: Peter Baumann
> Cc: Linda van den Brink; Svensson, Lars; Kerry Taylor; public-sdw-wg@w3.org;
> Frans Knibbe; Alejandro Llaves
> Subject: Re: Issue-10 unresolved in meeting today
> 
> +1 also from me.
> 
> Moreover, I would suggest we refer explicitly to "HTTP URIs".
> 
> Andrea
> 
> On Thu, Jun 25, 2015 at 9:42 AM, Peter Baumann
> <p.baumann@jacobs-university.de> wrote:
> > +1 as it is more technically motivated.
> > -Peter
> >
> > On 06/25/15 09:23, Linda van den Brink wrote:
> >> Hi all,
> >>
> >> What if we turn the phrasing around a bit. (as I suggested yesterday in the
> IRC channel, but this may have been missed)
> >>
> >> Then, the requirement is: to be able to reference a CRS with a URI, and to
> get useful information about the CRS when you dereference that URI.
> >>
> >> This implies a method for describing CRSs.
> >>
> >> I believe this phrasing is closer to Ed's point, at least as I understood it
> yesterday.
> >>
> >> Linda
> >>
> >> -----Oorspronkelijk bericht-----
> >> Van: Svensson, Lars [mailto:L.Svensson@dnb.de]
> >> Verzonden: woensdag 24 juni 2015 18:19
> >> Aan: Kerry Taylor; public-sdw-wg@w3.org
> >> CC: Frans Knibbe; Alejandro Llaves
> >> Onderwerp: RE: Issue-10 unresolved in meeting today
> >>
> >> Kerry,
> >>
> >> On Wednesday, June 24, 2015 5:22 PM, Kerry Taylor wrote:
> >>
> >>> I wonder whether I could explain my position expressed in the meeting
> >>> today better in email. To me,
> >>>
> >>> 1. It is a reasonable and much supported  requirement that CRSs need
> >>> to be described (somehow,  and I leave this how open for the purpose
> >>> of a requirement), and that a CRS can be referenced by a URI.  Hence
> Frans'
> >>> proposal or something very similar works for me. That is, "There
> >>> should be a best practice for publishing data about coordinate
> >>> reference systems (CRS). It should be applicable to any 2D or 3D CRS,
> >>> not only geographical reference systems. CRS descriptions should be
> >>> referencable by HTTP URIs."
> >>> We could take out the "by http URIs" I guess as that is a 'how' but
> >>> that is so obvious I think it should be left in nevertheless. We could
> >>> change "best practice" to "a way" or "a method"  and I am just as
> >>> happy. For me, "data about" does not imply rdf, nor natural language
> >>> text, nor any other form of description, but if it does to others,  I
> >>> would be just as happy with "descriptions of" instead.
> >> Works for me and I like the "descriptions of" since that is technology neutral.
> The important parts are description and referencability. I see this requirement
> as being related to but independent of 2. (below).
> >>
> >>> 2. It is not so clear, and indeed hotly disputed, about whether
> >>> spatial data on the web *must* reference a CRS. It might be that some
> >>> CRS is assumed by default, but not explicitly referenced. It might be
> >>> that the whole idea of a CRS is too difficult for non-experts and
> >>> should be assumed away.
> >> Well it *is* difficult for non-experts. I was lucky to get much help and
> support from some of the people on this list when I needed to understand how
> all the bits and pieces (ellipsoid, datum, axis order, ...) fit together and why
> they are important. OTOH I now know how important they are and given that
> we are not only talking about geographic CRSs but also custom ones (my
> computer is at (0,10): that is zero centimetres to the right and ten centimetres
> in front of me) at least in some cases the CRS must be specified for the data to
> make sense (or at least be interpreted properly).
> >>
> >>> Number 1 above stands nevertheless
> >>> for at least those cases where a CRS  *is* desired.  And we now have a
> >>> separate requirement to discuss about whether it should be possible to
> >>> implicitly refer to a default CRS ( issue-28).
> >>>
> >>> My own opinion on 2 above, developed by watching the comments on this
> >>> list and at Barcelona, is that we should try to make explicitly
> >>> referencing a CRS both trivially easy and mandatory, so that it is
> >>> explicit even if a beginner does not realise that it is there. This
> >>> way we take advantage of the cultural copy- and-paste practice yet
> >>> enable that culture to vary over time and space and application
> >>> domain, ie getting it right most of the time for both publishers and
> consumers without even thinking about it.
> >> Mandating an explicit reference does have the advantage that your data is
> not misinterpreted just because you omit the CRS (for whatever reason) and
> the consuming application reverts to the default CRS. This is a Good Thing
> (TM). OTOH it then really needs to be "trivially easy" to make that explicit and
> that might be really hard to achieve since you need to understand what a CRS is
> before you can specify which one you use (see above).
> >>
> >>> Chris raised an interesting idea about using content negotiation to
> >>> request a particular crs and getting whatever is asked for dynamically
> >>> ( I think that is what he meant). This sounds attractive to me ( but,
> >>> not to get distracted, is in solution space, not requirement space, I
> >>> think) and I would want to know that this is not going to be too much
> >>> of a challenge for data publishers. But that is a topic for another day.
> >> What would the requirement be?
> >>> Do you think we can resolve issue-10 next week?
> >> We SHOULD try!
> >>
> >> Best,
> >>
> >> Lars
> >
> > --
> > 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)
> >
> >
> >
> 
> 
> 
> --
> Andrea Perego, Ph.D.
> Scientific / Technical Project Officer
> European Commission DG JRC
> Institute for Environment & Sustainability
> Unit H06 - Digital Earth & Reference Data
> Via E. Fermi, 2749 - TP 262
> 21027 Ispra VA, Italy
> 
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> 
> ----
> The views expressed are purely those of the writer and may
> not in any circumstances be regarded as stating an official
> position of the European Commission.

Received on Thursday, 25 June 2015 08:20:05 UTC