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Re: [w3photo] Image regions

From: Benjamin Nowack <bnowack@appmosphere.com>
Date: Wed, 21 Jan 2004 10:07:41 +0100
To: Morten Frederiksen <mof-rdf@mfd-consult.dk>
Cc: semantic-photolist@unitboy.com
Message-ID: <PM-EH.20040121100741.A892A.1.1D@>

wow. fast you have been (as yoda might say).

some comments/notes/ideas:

- I'd like this single "coords" prop for all Regions
  (btw, the example still uses "points" for some regions)

- I would prefer space separated points (i.e. {0,0 100,100}
  instead of {0,0,100,100}. It would be easier to split for me.
  But I guess you had your reasons.

- what about subclassing Polygon and Ellipse, so that
  w3p:Circle rdfs:subClassOf w3p:Ellipse and
  w3p:Rectangle rdfs:subClassOf w3p:Polygon.
  This would lead to only two basic shapes/region types that 
  a tool would need to support. (plus the optional boundingBox)

anyway, great work.


Benjamin Nowack

Kruppstr. 82-100
45145 Essen, Germany

On 21.01.2004 01:00:49, Morten Frederiksen wrote:
>Hi there,
>We had an IRC chat meet tuesday on parts of images, and Jim and I was
>actioned to send a schema and sample document, based on the agreement
>We discussed photos versus multimedia, but decided that since the project
>starts out with just photos, we would just leave room in the model for
>later additions of other types of media. Also because of this, it was
>decided that the classes and properties would be named specifically for
>photos, as general names were hard to find.
>We looked at the schemas currently out there, including Jim's new thoughts
>[1], Jennifer's [2] and Masahide's [3], and came up with the following
>classes and properties (we didn't discuss the namespace, so the
>BuildOrBuyTerms issue is still open):
>- Image
>- Region (subclassed into Polygon, Circle etc.)
>- hasRegion (with inverse regionOf)
>  * domain: Image
>  * range: Region
>- regionDepicts (with inverse regionDepiction)
>  * domain: Region
>  * range: Resource (Person, perhaps a wordnet concept, anything etc.)
>With this schema [4] (example: [5]), it should be possible to later add 
>superclasses and -properties to include other types of multimedia.
>Additional notes:
>- The inverse properties were added post-meeting.
>- The word "region" was debated, other suggestions included segment,
>  section, area, part, shape, thingy, element, segmentation, extent and
>  component. For photos region was agreed upon as the best option.
>- We decided that, for now, it'd be best to keep a depicts property
>  with a domain of Image separate from regionDepicts, to avoid confusing
>  existing tools that expect a URI for the subject.
>Later we discussed how to describe the region itself. We agreed that this
>should be a simple literal property, for ease of use and to avoid security
>issues, validating/handling SVG in general doesn't seem feasible for
>We agreed to disagree on the modelling of the description, but agreed on
>SVG and came up with two approaches and two extensions:
>- A single property for alle types of regions, using SVG's general
>  path-syntax [6], with a property name like "outline".
>  + With this approach, it could be handy with a boundingBox property
>    alongside the outline property. The bounding box would then be
>    computed by clients generating "complex" shapes, and consumed by
>    clients not able to handle those shapes. This property would be a
>    "SHOULD" in the "spec" (as opposed to the outline, which would be
>    a "MUST").
>- A property for each type of region, named after the region type, using
>  a subset of SVG's basic shapes [7]: circle, ellipse and polygon
>  (instead of polyline, to avoid repeating end-point, and semantics of
>  polyline indicate that "typically, polyline elements define open
>  shapes").
>  + It could be handy to also include rect[angle] in this list, even if
>    it's a subset of polygon.
>After the meeting, Jim and I discussed the issue again [8], reaching
>a compromise for a solution proposal:
>- One property, coords, for circle, polygon and rectangle, with a domain of
>  Region and a range of Literal. To keep compatibility with HTML image
>  maps [9] and SVG, it seems the syntax from the former (which is also
>  acceptable by the latter) should be adapted, with circles being defined
>  by "point,radius", rectangles by "point,point" and polygons by
>  "point,point,...". Separation of coordinates in a point is also done by
>  ",", only integer coordinates are allowed, and the ending point in a
>  polygon is omitted (auto-close).
>- An ellipse could be defined by "point,x-radius,y-radius", which would
>  be compatible with SVG but not HTML image maps. A fallback method
>  could be to transform it into a circle, using the larger radius.
>- The interpretation of the coords property is done by inspecting a
>  suitable rdf:type property of the Region (Circle, Polygon, Rectangle or
>  Ellipse).
>- Additional, more complex region types could be added at a later date
>  by using SVG's path syntax.
>- A boundingBox property MAY be added by generating client, but could
>  be computed easily for the basic shapes. When using more complex shapes
>  and SVG's path syntax, the boundingBox property SHOULD be added.
>Jennifer and Masahide couldn't make the meeting, but we hope they will
>chime in here on the list instead, nothing is set in stone...
>[1] http://jibbering.com/discussion/image.1
>[2] http://www.mindswap.org/~glapizco/technical.owl
>[3] http://kanzaki.com/works/2004/imgdsc/0106.html
>[4] http://www.wasab.dk/morten/2004/01/image-regions-schema.rdf
>[5] http://www.wasab.dk/morten/2004/01/image-regions-sample.rdf
>[6] http://www.w3.org/TR/SVG11/paths.html
>[7] http://www.w3.org/TR/SVG11/shapes.html
>[9] http://www.w3.org/TR/html401/struct/objects.html#h-13.6.1
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Received on Wednesday, 21 January 2004 04:14:12 UTC

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