Datalink vocabulary

Mon Sep 15 21:26:38 CEST 2014

Yeah, this. Since the whole site was moving when I got the .htaccess 
stuff from Norman, I decided to wait until everything was transfered to 
the new hosts before embarking on this config bit. So, now is the time 
to set that up right.

The source that can build a zip file to send to the document coordinator 
is all in volute and, following the way Apps-WG handles mtypes I think 
we previously decided that the we would approve vocabulary changes via 
WG discussion and then the chair/vice-chair or someone they designate 
could modify the source and create a new version to deploy on the web site.

IMO, we should live with what's there now (html page) and work on the 
content; the technicalities can be fixed in the next upload.

Pat

PS-Working on the PR document w.r.t. RFC page comments right now. I see 
one outstanding issue that I'll post separately in the next day or so.

On 11/09/14 05:09 AM, Norman Gray wrote:
>
> Markus and all, hello.
>
> On 2014 Sep 11, at 09:15, Markus Demleitner <msdemlei at ari.uni-heidelberg.de> wrote:
>
>> Dear DAL,
>>
>> [taking the discussion from interop to DAL]
>>
>> On Thu, Jul 31, 2014 at 08:54:43AM +0200, François Bonnarel wrote:
>>>     Thanks to Mireille, Laurent, Norman, Pat and Sarah the datalink
>>> vocabulary for semantics of the links in DataLink is now available
>>> here:
>>> http://www.ivoa.net/rdf/datalink/
>
> These aren't currently working as they should:
>
> % pwd
> /checkouts/code.google.com/volute/trunk/projects/dal/DataLink/datalink-terms
> % make check-dist
> ./check-uris.sh
> Failed: http://www.ivoa.net/rdf/datalink/core [accept:text/html]
>      produced status=404, Location=
>      expected status=303, Location=http://www.ivoa.net/rdf/datalink/2014-08-01/datalink-core-2014-08-01.html
> Failed: http://www.ivoa.net/rdf/datalink/2014-08-01/datalink-core-2014-08-01.html
>      produced status=404
>      expected status=200
> Failed: http://www.ivoa.net/rdf/datalink/core []
>      produced status=404, Location=
>      expected status=303, Location=http://www.ivoa.net/rdf/datalink/2014-08-01/datalink-core-2014-08-01.html
> Failed: http://www.ivoa.net/rdf/datalink/core [accept:text/turtle]
>      produced status=404, Location=
>      expected status=303, Location=http://www.ivoa.net/rdf/datalink/2014-08-01/datalink-core-2014-08-01.ttl
> Failed: http://www.ivoa.net/rdf/datalink/2014-08-01/datalink-core-2014-08-01.ttl
>      produced status=404
>      expected status=200
> Failed: http://www.ivoa.net/rdf/datalink/core [accept:application/rdf+xml]
>      produced status=404, Location=
>      expected status=303, Location=http://www.ivoa.net/rdf/datalink/2014-08-01/datalink-core-2014-08-01.rdf
> Failed: http://www.ivoa.net/rdf/datalink/2014-08-01/datalink-core-2014-08-01.rdf
>      produced status=404
>      expected status=200
> Failed: http://www.ivoa.net/rdf/datalink/datalink-core-2014-08-01.tar.gz
>      produced status=404
>      expected status=200
> Some tests failed.  Boo!
> %
>
> (this test is in volute: trunk/projects/dal/DataLink/datalink-terms/)
>
> I suspect that the .htaccess file (in the distribution .tar.gz file) isn't installed quite correctly.  The following should produce a 303 redirection:
>
> % curl -i http://www.ivoa.net/rdf/datalink/core
> HTTP/1.1 404 Not Found
> Date: Thu, 11 Sep 2014 11:12:11 GMT
> Server: Apache/2.2.15 (CentOS)
> Content-Length: 293
> Connection: close
> Content-Type: text/html; charset=iso-8859-1
>
> <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
> <html><head>
> <title>404 Not Found</title>
> </head><body>
> <h1>Not Found</h1>
> <p>The requested URL /rdf/datalink/core was not found on this server.</p>
> <hr>
> <address>Apache/2.2.15 (CentOS) Server at www.ivoa.net Port 80</address>
> </body></html>
> %
>
>> One thing I notice is that the "self" thing I've advocated is missing
>> (to mark up the link to the primary dataset); however, I think it is
>> important, as for some of the existing datalink prototypes, access to
>> the full dataset is *only* possible through datalink, and clients
>> need a robust way to discover what link to use to retrieve it.
>
> That sounds wise, and is easy to add.
>
>> I'd also like to make the terms more self-contained, as I expect most
>> clients will, at least initially, have to work on these exclusively
>> rather than have our little ontology.  And of course, neither
>> publishers nor users can be expected, in general, to know the model.
>> So, they'd not see #preview/image, they'd just see #image, and they'd
>> be confused to see what's coming back is a preview.  This, in
>> particular, concerns
>>
>> image (-> preview-image)
>> plot  (-> preview-plot)
>> proprietary (-> ? -- I'm pretty sure rather than give that publishers
>>   should be encouraged to use the other categories -- after all, all
>>   data conform to *some* data model; so, they should rather say "this
>>   is a characterisation" than "this is in some proprietary data
>>   model)
>
> Changing #image to #preview-image would be an easy change to make (though obviously not backward-compatible, though it's obviously too early to be worried about that).
>
>> Also, without having read the Turtle specs, I'm pretty sure the #
>> shouldn't be part of the names in the TTL file; the way this is
>> written would imply, I guess, that the full form of these terms would
>> be http://www.ivoa.net/rdf/datalink##preview -- which we certainly don't
>> want.  Norman?
>
> You may be misremembering the URI resolution algorithm.
>
> If you do:
>
>      % rapper -iturtle -ontriples .../foo.ttl
>
> you see the sequence of triples in the most unadorned form, with all URIs fully resolved.  For example the #image ones are:
>
> <http://www.ivoa.net/rdf/datalink/core#image> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://www.w3.org/1999/02/22-rdf-syntax-ns#Property> .
> <http://www.ivoa.net/rdf/datalink/core#image> <http://www.w3.org/2000/01/rdf-schema#subPropertyOf> <http://www.ivoa.net/rdf/datalink/core#preview> .
> <http://www.ivoa.net/rdf/datalink/core#image> <http://www.w3.org/2000/01/rdf-schema#label> "Quick look image" .
> <http://www.ivoa.net/rdf/datalink/core#image> <http://www.w3.org/2000/01/rdf-schema#comment> "For example, an XMM spectral preview" .
>
> All the best,
>
> Norman
>
>

-- 

Patrick Dowler
Canadian Astronomy Data Centre
National Research Council Canada
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