W3C home > Mailing lists > Public > public-openannotation@w3.org > June 2013

Using JP2000 images as bodies/targets of annotations

From: James Smith <jgsmith@gmail.com>
Date: Tue, 18 Jun 2013 09:00:22 -0400
Message-Id: <A18C68AA-C6D5-48CB-897B-ED9837D0CE6B@gmail.com>
To: public-openannotation <public-openannotation@w3.org>
This might also be relevant for Shared Canvas, but I figured the basic idea is more Open Annotation than Shared Canvas.

We're building out a Shared Canvas digital facsimile edition of Shelley's Frankenstein notebooks (among other of her family's papers). Our grant requires that we use scalable images for the page scans (e.g., something like OpenSeadragon). We've settled on JP2000 and djatoka for providing the tiles.

The result is that we aren't annotating the canvas with a single zoom level, pixel density, etc., version of the image, but with the JP2000 image assuming that the client will select the appropriate pixel density and tiling for the given view window onto the canvas.

If we were assuming that only a single zoom level was annotating the canvas, we'd be done simply by using the appropriate URL to retrieve the full image at the right size.

Instead, we want to construct an annotation that has the JP2000 image as the body, but not restrict the rendering to a particular version of the JP2000 image. We can think of two ways to do this.

(1) Construct an annotation with the body's specific resource being a URL that retrieves the JP2000 image in some other format by referencing a djatoka server in the URL. This does not seem to fit the intent of the annotation, but allows current browsers with no knowledge of JP2000 to gracefully degrade. It does require a djatoka-aware viewer to parse the URL, which seems counter to how we want linked data to work.

<anno1> a oa:Annotation ;
  oa:motivatedBy sc:painting ;
  oa:hasBody <content1> ;
  oa:hasTarget <canvas1> .

<canvas1> a sc:Canvas ;
  exif:height 1400 ;
  exif:width 1000 ;
  rdfs:label "Page 1" .

<image1> a dctypes:Image ;
  dc:format "image/jpeg" .

(with <image1> being a URL constructed to return a particular rendering of a JP2000 through djatoka).

(2) Construct an annotation with the body's specific resource being the URL of the JP2000 image with an additional property pointing to the djatoka server that can be used to retrieve various versions of the image. This does not require special parsing of URLs, but won't work if a browser doesn't understand JP2000.

<anno1> a oa:Annotation ;
  oa:motivatedBy sc:painting ;
  oa:hasBody <content1> ;
  oa:hasTarget <canvas1> .

<canvas1> a sc:Canvas ;
  exif:height 1400 ;
  exif:width 1000 ;
  rdfs:label "Page 1" .

<image1> a oa:SpecificResource ;
  dc:format "image/jp2" ;
  oa:hasSource <source1> ;
  sc:hasRelatedService <djatokaService1> .

I'm leaning towards (2) because it's cleaner from a LoD perspective even if the browser doesn't work quite right. In this case, the question is which property should indicate the recommended djatoka server? Shared Canvas as a sc:hasRelatedService property, but I'm wondering if there's something more appropriate that people have used already.
Received on Tuesday, 18 June 2013 13:00:52 UTC

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