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Re: Content negotiation of spatial linked data

From: Andrea Perego <andrea.perego@jrc.ec.europa.eu>
Date: Mon, 26 Sep 2016 13:14:41 +0200
To: Andreas Harth <harth@kit.edu>, Maxime Lefrançois <maxime.lefrancois.86@gmail.com>, "Svensson, Lars" <L.Svensson@dnb.de>, Joshua Lieberman <jlieberman@tumblingwalls.com>
Cc: SDW WG Public List <public-sdw-wg@w3.org>
Message-id: <c95f22d1-5576-585e-174a-891fd82bf404@jrc.ec.europa.eu>
Hi, Andreas.

On 23/09/2016 01:03, Andreas Harth wrote:
> Hi,
>
> On 09/22/16 22:32, Maxime Lefrançois wrote:
>> Dear all,
>>
>> my two cents:
>>
>>
>>> Particular serializations of both the feature and geometry data can
>>> be
>> negotiated either way, I
>>> think. If one request a feature with contentType
>>> application/rdf+xml; geomdata=“WKTLiteral”, then the geometry if
>>> requested / returned
>> should include an
>>> asWKT.
>>
>> While I agree that this would be very handy indeed, I don't think
>> http allows that kind of syntax in the Accept-header, at least not
>> for all media types and certainly not for application/rdf+xml
>>
>>
>> using
>>
>> Accept: application/rdf+xml;geomdata="WKTLiteral"
>>
>> Would be perfectly ok as per RFC 2045 and updated by RFC 2184. But
>> parameter geomdata is neither defined as a required, nor as an
>> optional parameter in media type application/rdf+xml.
>> http://www.iana.org/assignments/media-types/application/rdf+xml
>>
>> What could be possible on the other hand, would be to define a new
>> media type such as application/geomdata+rdf+xml for instance (not
>> sure if the use of two '+' would be allowed, I can ask. and to
>> register it following https://www.w3.org/2001/tag/2004/0430-mime
>
> a straightforward alternative is to give the geometry a URI and do
> plain content negotiation.  Problem solved.

I'm also in favour of this approach, although I recognise we should 
provide guidance even for use cases where geometries are embedded in RDF 
graphs.

> I do not understand why people would bend over backwards to put
> possibly very large GML/WKT/KML data (or other "binary" content) in
> RDF literals.
>
> Cheers,
> Andreas.
>
> PS. FWIW, it would be useful to have a IANA-registered content type
> for WKT and GML [1].  KML and GeoJSON have one.

+1. Makes perfect sense to me.

-Andrea

> [1] http://www.iana.org/assignments/media-types/media-types.xhtml
>

-- 
Andrea Perego, Ph.D.
Scientific / Technical Project Officer
European Commission DG JRC
Directorate B - Growth and Innovation
Unit B6 - Digital Economy
Via E. Fermi, 2749 - TP 262
21027 Ispra VA, Italy

https://ec.europa.eu/jrc/

----
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 Monday, 26 September 2016 11:15:38 UTC

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