[annotator-dev] RFC: new ideas for specifying image regions

Robert Casties casties at mpiwg-berlin.mpg.de
Wed Feb 5 16:43:37 UTC 2014

Hi Rob,

On 05.02.14 17:01, Robert Sanderson wrote:
> Is there an issue with what Open Annotation recommends, being the xywh
> media fragment for rectangular bounding boxes, and SVG for everything else?

The media fragment stuff is not enough as its only rectangular and only
pixels or (integer) percent and SVG is too much as it allows arbitrary
coordinate systems and transforms and its XML.

> http://www.openannotation.org/spec/core/core.html#FragmentURIs
> http://www.openannotation.org/spec/core/specific.html#SvgSelector

You have to specify a subset of SVG like the spec says and you have to
somehow deal with the XML as the spec says.

I am currently only looking for a solution that is easily parseable as
JSON to be used by an Annotator.js plugin.

I would like the format to be close to what is used by OAC but I am not
satisfied with the current choice of only media fragment or SVG. I would
like to talk with other people implementing image annotations to see if
we could maybe come up with a better selector for this use case.


> On Wed, Feb 5, 2014 at 6:29 AM, Robert Casties
> <casties at mpiwg-berlin.mpg.de>wrote:
>> I am starting to work again on our image annotation tool for our image
>> server digilib. I want to implement polygon-shaped image regions too and
>> I have been rethinking the JSON-format for specifying image regions.
>> After looking at GeoJSON (http://geojson.org/geojson-spec.html) I have
>> reworked our annotation format slightly:
>> <
>> https://it-dev.mpiwg-berlin.mpg.de/tracs/Annotations/wiki/json-annotation-format
>> To be close to GeoJSON the "type" of the shape is now in the "geometry"
>> object.
>> Also from GeoJSON I took the idea to specify the shapes only by points
>> and not lengths. So the Rectangle is specified by two corner points
>> instead of one point, height and width. This also makes coordinate
>> transformations easier.
>> GeoJSON does not have a Rectangle type, only Polygon (which makes sense
>> when working with different coordinate systems). Should we also rather
>> specify the rectangles as polygons?
>> I also thought about renaming the member for the image region in the
>> annotation from "shapes" to "regions" which would make it easier to deal
>> with the older format. Or should I stick with "shapes", what do you think?
>> Thanks
>>         Robert
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Dr. Robert Casties -- Information Technology Group
Max Planck Institute for the History of Science
Boltzmannstr. 22, D-14195 Berlin
Tel: +49/30/22667-342 Fax: -299

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