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RE: New Exif/RDF vocabulary

From: Hausenblas, Michael <michael.hausenblas@joanneum.at>
Date: Fri, 8 Aug 2008 20:34:31 +0200
Message-ID: <768DACDC356ED04EA1F1130F97D29852014C62B6@RZJC2EX.jr1.local>
To: "Tim Berners-Lee" <timbl@w3.org>, "KANZAKI Masahide" <mkanzaki@gmail.com>
Cc: "SW-forum Web" <semantic-web@w3.org>, "Ivan Herman" <ivan@w3.org>, "Norman Walsh" <ndw@nwalsh.com>

 
Tim, Kanzaki,
 
> Should a group be standardizing the exif ontology, do people think?

Yes. How about [1]? We had a good start last year [2] - why not using the momentum for something valuable such as Exif.
 
Cheers,
      Michael
 
[1] http://www.w3.org/2008/01/media-annotations-wg.html <http://www.w3.org/2008/01/media-annotations-wg.html> 
[2] http://www.w3.org/2005/Incubator/mmsem/XGR-vocabularies/ <http://www.w3.org/2005/Incubator/mmsem/XGR-vocabularies/> 
 
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________________________________

From: semantic-web-request@w3.org on behalf of Tim Berners-Lee
Sent: Fri 2008-08-08 20:07
To: KANZAKI Masahide
Cc: SW-forum Web; Ivan Herman; Norman Walsh
Subject: Re: New Exif/RDF vocabulary




Kanzaki,

I have only now looked at it.  The tools look nice.

I have one comment about the modeling.

Looking at for example

  http://www.kanzaki.com/test/exif2rdf?u=http://web.canon.jp/Imaging/ixy30/SPL/IMG_0138.JPG <http://www.kanzaki.com/test/exif2rdf?u=http://web.canon.jp/Imaging/ixy30/SPL/IMG_0138.JPG> 

there is what seems to be an extra arc "exifdata" to a bnode labelled 
"Exif Image File Data", and then the exposureTime is a property of the 
exifdata, not of the original phototo.
The arc seems to be used to group the data in the file, but I would 
find it more useful I think
to define the exposureTime as a property of the picture itself.

I like the modeling of  the various enumeration types I think make 
sense, such as YCbCr vs sRGB etc.

I would be more inclined to model units using predicates. Instead of 
(in N3)

             exif:focalPlaneResolutionUnit
                exif:inches;
             exif:focalPlaneXResolution
                "9846.15384615";
             exif:focalPlaneYResolution
                "9846.15384615";

I would be inclined to use

             exif:focalPlaneXResolution
                [ exif:inches "9846.15384615" ];
             exif:focalPlaneYResolution
                [ exif:inches "9846.15384615"];

You can the for example deduce what the exif:focalPlaneYResolution of 
something is in meters without any contradictions.


             exif:focalPlaneXResolution
                [ exif:inches "9846.15384615" ; unit:m "250.0"];
             exif:focalPlaneYResolution
                [ exif:inches "9846.15384615"; unit:m "250.0"];

(Hmm .. in this example it looks as though the meters was probably the 
original figure!)

or even

             exif:focalPlaneXResolution
                [ exif:inches 9846.15384615 ; unit:m 250.0];
             exif:focalPlaneYResolution
                [ exif:inches 9846.15384615 ; unit:m 250.0];


I made a simple suitable units ontology by the way at http://www.w3.org/2007/ont/unit <http://www.w3.org/2007/ont/unit> 

Should a group be standardizing the exif ontology, do people think?
How stable is the http://www.kanzaki.com/ns/exif <http://www.kanzaki.com/ns/exif>  namespace?
Would you like a w3.org namespace for it?

Keep up the good work!

Tim
______________________________
excerpt from the exit example mentioned above:

  <foaf:Image rdf:about="http://web.canon.jp/Imaging/ixy30/SPL/IMG_0138.JPG <http://web.canon.jp/Imaging/ixy30/SPL/IMG_0138.JPG> 
">
   <dc:date>2003-01-18T16:07:30</dc:date>

<!-- Metadata from Exif section -->
   <make>Canon</make>
   <model>Canon IXY DIGITAL 30</model>

   <orientation rdf:resource="http://www.kanzaki.com/ns/exif#right- <http://www.kanzaki.com/ns/exif#right-> 
top"/>
   <xResolution rdf:datatype="&xsd;decimal">180</xResolution>
   <yResolution rdf:datatype="&xsd;decimal">180</yResolution>
   <resolutionUnit rdf:resource="http://www.kanzaki.com/ns/ <http://www.kanzaki.com/ns/> 
exif#inches"/>
   <dateTime>2003-01-18T16:07:30</dateTime>
   <yCbCrPositioning rdf:resource="http://www.kanzaki.com/ns/exif#centered <http://www.kanzaki.com/ns/exif#centered> 
"/>
   <exif-info>

    <Exif_IFD rdfs:label='Exif Image File Data'>
     <exposureTime rdf:datatype="&xsd;decimal">0.0025</exposureTime>
     <fNumber rdf:datatype="&xsd;decimal">3.5</fNumber>
     <exifVersion>0220</exifVersion>



[1] http://www.w3.org/2001/sw/BestPractices/MM/interop.html <http://www.w3.org/2001/sw/BestPractices/MM/interop.html> 

On 2007-12 -13, at 11:50, KANZAKI Masahide wrote:

>
> Hello all,
>
> Several years after my release of Exif RDF vocabulary [1], I updated
> the schema with some significant changes.
>
> The old vocabulary was defined as RDF schema and no rdfs:domain and
> rdfs:range were provided for property descriptions. While many of Exif
> tag values come just as numbers, how to describe those values in RDF
> was not cleary defined.
>
> This time, I redefined the vocabulary as OWL ontology, so that tags
> whose values have pre-defined interpretation are defined as
> owl:ObjectProperty, and their possible values as resources denoted by
> URIs. Also, domain of properties are defined (via super properties) so
> as Exif's IFD structure to be retained in the RDF data.
>
> Although those changes made the new definition incompatible with the
> old one, I would keep its namespace URI [1 + '#'] intact. If you need
> old definition vocabulary (which might be easier to use in
> hand-writing), its copy is available at W3C with somewhat authentic
> URI [2]. I will finalize this change within a week unless any
> objection (e.g. assign different URI for new definition).
>
> For users convenience, the new definition comes with a JSON file [3]
> which provides mapping from Exif tags/values to RDF
> properties/value-resources. A sample Web application to extract RDF
> from image file [4] now uses the new definition.
>
> Comments, suggestions are welcome, of course.
>
> thanks,
>
> [1] http://www.kanzaki.com/ns/exif <http://www.kanzaki.com/ns/exif> 
> [2] http://www.w3.org/2003/12/exif/ns <http://www.w3.org/2003/12/exif/ns> 
> [3] http://www.kanzaki.com/ns/exif-tags.json <http://www.kanzaki.com/ns/exif-tags.json> 
> [4] http://www.kanzaki.com/test/exif2rdf <http://www.kanzaki.com/test/exif2rdf> 
>
>
> --
> @prefix : <http://www.kanzaki.com/ns/sig# <http://www.kanzaki.com/ns/sig#> > . <> :from [:name
> "KANZAKI Masahide", "????"; :email "mkanzaki@gmail.com"].
>
Received on Friday, 8 August 2008 18:35:15 GMT

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