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E46 Section Definition, E47 Spatial Coordinates

Question

We got some data on Rembrandt paintings like this:

Meaning: someone used a microscope to look at paint layers located (6, 13.2) cm from the bottom left corner of the painting.

Similarly, in the ResearchSpace system we'll have Image Annotation functionality, so a user can say anything about a particular image location (or region).

How to represent this in CIDOC CRM?

Unfortunately neither includes specific properties to provide coordinates, etc.
E.g. I can state such esoteric fact as E47_Spatial_Coordinates. P105 right held by: E39 Actor
but I cannot state WHAT the coordinates are

I've started looking at previous work on Image Annotation and so far found this:

AO Selectors (see Annotation, Discussion Tools#Annotation Ontology for info)
"Init End Corner Selector" allows to specify a rectangle, e.g.:

I don't like it particularly since:

  • data is not broken into separate fields and there are no xsd types
  • units cannot be specified (presumably these are pixels)
  • you can only attach it to images but not objects (e.g. paintings)
  • you cannot have flexibility in specifying the origin (that doesn't matter on a precise pixelated image, but matters on an irregular real-world shape)

I think the best is to somehow combine E46 Section Definition and E47 Spatial Coordinates,
and attach Type properties about origin, and Dimensions about the precise position.

Can anyone offer some advice on Image Annotation?

Answers

Martin Doerr

The CIDOC CRM is, as any ontology, extensible and made for extension.

You can declare a subclass of E47. See scope note:
"This class comprises the textual or numeric information required to locate specific instances of E53 Place within schemes of spatial identification. Coordinates are a specific form of E44 Place Appellation, that is, a means of referring to a particular E53 Place. Coordinates are not restricted to longitude, latitude and altitude. Any regular system of reference that maps onto an E19 Physical Object can be used to generate coordinates."

You can declare a class "rectangular_canvas_coordinates" as below, or "rectangular_flat_object_coordinates".
Please have in mind that global queries on such coordinates hardly make any sense:
In order to make sense, either many data with many coordinates on the same object should exist, or many objects with comparable features at the same relative location. Both cases are extreme specializations. For all other applications, these coordinates are just informative, i.e. should come as result, but are not required for analytical queries on values.

- these are places defined on a physical object, so E46 Section Definition seems appropriate

- they also have coordinates, so E47 Spatial Coordinates seems appropriate

Yes, good point.

Unfortunately neither includes specific properties to provide coordinates,

Yes, not "unfortunately", but "fortunately", because you can propose meaningful extensions. Keep in mind that there are hundreds of reasonable coordinate systems, for instance on maps. Do you really suggest CRM should standardize all of them? This is a question of modularity of ontologies. Staying within one's field of expertise....

http://code.google.com/p/annotation-ontology/wiki/Selectors

- you cannot have flexibility in specifying the origin (that doesn't matter on a precise pixelated image, but matters on an irregular real-world shape)

Please keep in mind, that a Digital Image is immaterial, there is NO place in the sense of the CRM on it. On your Rembrandt however, there is!

> I think the best is to somehow combine E46 Section Definition and E47 Spatial Coordinates

agreed

> and attach Type properties about origin,

agreed

> and Dimensions about the precise position.

No, not Dimensions. Just:

  • "location_hor"
  • "location_vert"
  • and unit.

Better, however, rectangles!

> Can anyone offer some advice on Image Annotation?

See for instance METS <area> definitions!

Oyvind Eide

Maximilian Schich

(http://www.schich.info)

Thomas Wikman

Another tool: YUMA

Martin Warnke

We worked on the subject for quite a long time. Our results could be inspected at

Misc

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