[Crm-sig] P90 etc.

Robert Sanderson RSanderson at getty.edu
Thu Mar 8 20:26:26 EET 2018


Well … as a response to that call …

CRM implementations using rdf:value:


·         The American Art Collaborative uses rdf:value, consisting of Amon Carter Museum of American Art, Archives of Americant Art (Smithsonian), Autry Museum of the American West, Colby College Museum of Art, Crystal Bridges Museum of American Art, Dallas Museum of Art, Indianapolis Museum of Art, Thomas Gilcrease Institute of American History and Art, National Portrait Gallery (Smithsonian), National Museum of Wildlife Art, Princeton University Art Museum, Smithsonian American Art Museum, Walters Art Museum, Yale Center for British Art

·         The Getty Museum and Research Institute use rdf:value

·         The National Museum of Australia uses rdf:value

·         The Georgia O’Keefe Museum uses rdf:value

·         Historic England uses rdf:value (IIRC, Phil can confirm or deny)


Implementers of the IIIF specifications use rdf:value for the same purpose, which comprises hundreds of organizations around the world, primarily in academia and cultural heritage.  http://iiif.io/api/presentation/

Implementers of the W3C Web Annotation Data Model use rdf:value for the same purpose.  https://www.w3.org/TR/annotation-model/#embedded-textual-body

According to lov.okfn.org, rdf:value is used in 44 datasets known to it , with 4.6M occurrences.  For comparison, crm:P3_has_note has no known usage in LOV.

If you want just pure usage numbers … schema:value would probably win hands down. Schema is implemented in 20-30% of all web pages.  And has, relatively recently, made process changes to be sufficiently stable to be accepted as a normative reference specification by the W3C.  However the semantics are even less precisely defined than rdf:value, and W3C is a much more likely standards body than Google.

YMMV.

Rob


From: Richard Light <richard at light.demon.co.uk>
Date: Thursday, March 8, 2018 at 9:29 AM
To: Robert Sanderson <RSanderson at getty.edu>, Martin Doerr <martin at ics.forth.gr>
Cc: George Bruseker <george.bruseker at gmail.com>, crm-sig <crm-sig at ics.forth.gr>
Subject: Re: [Crm-sig] P90 etc.

Rob,

I'm suggesting that we take a step back from this sort of ad hoc decision making, as noted two messages down.  We can come back to the question of which RDF properties to use once we are equipped with information on community practice as well as W3C/ISO norms.

If the group agrees, I propose to draft a call for examples of RDF practice which we can put out to the MCG and MCN lists (for the museum community), and to whatever library and archive lists we can find.

Richard
On 08/03/2018 16:28, Robert Sanderson wrote:

Martin,

Could you clarify why you have changed your mind about rdf:value?

> I recommend NOT to recommend rdf:value

In particular, in the last week you said:

“CRM-SIG normally works reactively: When a good community practice emerges, this is taken up.”

and

“Whatever the vast majority is  and rdf:value does the job, I have no objections to its use.
Just define precisely what you use it for. We can add that to our guidelines. It is already standard rdf.”

Thanks,

Rob


From: Crm-sig <crm-sig-bounces at ics.forth.gr><mailto:crm-sig-bounces at ics.forth.gr> on behalf of Richard Light <richard at light.demon.co.uk><mailto:richard at light.demon.co.uk>
Date: Thursday, March 8, 2018 at 12:02 AM
To: Martin Doerr <martin at ics.forth.gr><mailto:martin at ics.forth.gr>
Cc: George Bruseker <george.bruseker at gmail.com><mailto:george.bruseker at gmail.com>, crm-sig <crm-sig at ics.forth.gr><mailto:crm-sig at ics.forth.gr>
Subject: Re: [Crm-sig] P90 etc.


Martin,

Thanks for updating the string part of the RDF implementation doc.

I was thinking last night that maybe we should focus our RDF efforts on exactly this issue: the representation of the CRM primitive classes E60, E61 and E62 in RDF.  The current RDF document is becoming quite wide-ranging in its scope, and (for example) you have questioned whether certain sections belong in it.  If we concentrate on this single aspect of the broader RDF issue, I think we can produce something which is of practical value relatively quickly.  In particular, I would like to devote time to this during the Lyon meeting.

It seems to me that there are three elements which need to be considered when recommending an approach:

  *   the CRM's own view on what information should be expressible, and how (in an abstract sense) it should be represented
  *   RDF and other W3C/ISO recommendations and standards for representing string-type information
  *   the view of communities of practice on the issues involved, and the solutions they have come up with

In particular I think it important that we should consult widely on this issue, and be seen to take account of existing community practice.

Best wishes,

Richard
On 06/03/2018 17:54, Martin Doerr wrote:


Dear Richard,

It would be really great if you could join our next meeting!

We need your help to finish the RDF guidelines.
I have rewritten the string part in the google doc:



"Recording string
values

As

mentioned in point 3 above, the RDFS Schema does not implement the CRM primitive classes E60 Number, E61 Date or E62 String.  Instead it specifies rdfs:Literal as the range of properties which would otherwise take one of these values:

  *

·         P3_has_note

·          [String]

  *
  *

·         P57_has_number_of_parts

·          [Number]

  *
  *

·         P79_beginning_is_qualified_by

·          [String]

  *
  *

·         P80_end_is_qualified_by

·          [String]

  *
  *

·         P81_ongoing_throughout

·          [Time primitive] [but see Note 8 above and section on dates below]

  *
  *

·         P82_at_some_time_within

·          [Time primitive] [but see Note 8 above and section on dates below]

  *
  *

·         P90_has_value

·          [Number]

  *

The

recommended RDFS implementation of the CIDOC CRM may further refine the range of these properties to more specific datatypes, if not yet done.

Recording
names

Apart

from the seven properties listed above, there are a number of situations where the fully-worked-out path to a string value leads to an unduly long chain of classes and properties.  For example:

E55_Type > P1_is_identified_by

> E41_Appellation > P3_has_note > E62_String

Documenting

an instance of E41_Appellation with a URI of its own, is only useful if the instance is expected to be either an object of discourse regardless what it identifies, such as etymology or name variants etc., or if it needs an extended content model with meaningful

parts, such as a street address.

In

cases where there is nothing more to say about the E41_Appellation, P1_is_identified_by

should

be replaced by rdfs:label (“rdfs:label is an instance of

rdf:Property<https://www.w3.org/TR/rdf-schema/#ch_property>

that may be used to provide a human-readable version of a resource's name”, in: RDF Schema 1.1)

E55_Type > rdfs:label >

rdfs:Literal<https://www.w3.org/TR/rdf-schema/#ch_literal>.

Since

RDFS does not qualify the range of rds:label further, we cannot formally make rdfs:label a subproperty of

P1_is_identified_by

or vice-versa. We can

only register the convention and take care that query systems retrieve labels together with instances of

P1_is_identified_by

. The fact that the same

name “Martin Doerr” may appear in different encodings is inevitable. It is recommended to use name spelling conventions from library cataloguing rules and SKOS properties for instances of  E55_Type.

"

Please comment!
I have discussed with George that we should make several distinctions:

Only digitized content can be stored in-line in the KB as Literal.

There must be a comparable way to point to a digitized content via URI, URL, or literal. All representations of Symbolic Objects in electronic form are ambiguous wrt the the intended level of symbolic interpretation: Is it the bits, or the Latin1 characters, or characters + font make up its identity?

We must distinguish between digital content of a symbolic object, a general "note" about an individual, and values in a mathematical/ physical space.

I recommend NOT to recommend rdf:value:


"5.4.3 rdf:value rdf:value is an instance of rdf:Property<https://www.w3.org/TR/rdf-schema/#ch_property> that may be used in describing structured values. rdf:value has no meaning on its own. "

We definitely need a recommendation for names, regardless how complex it becomes.

When we created the RDF version, there were no datatype recommendations. Now, that there are, we should remove "rdfs:Literal from all properties in which it is unambiguous.

I kindly ask you to check https://www.w3.org/TR/2004/REC-rdf-mt-20040210/#dtype_interp for  compatible datatypes. This must be well-justified. E.g., "P57_has_number_of_parts [Number]" should have range:

"xsd:nonNegativeInteger", and not "xsd:decimal".

E60 Number could be any value from the mathematical multidimensional spaces made of real numbers, such as RGB images. We have no super-representation in RDFS/XSD. We can enumerate compatible datatypes:

"xsd:decimal<http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#decimal>, xsd:float<http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#float>, xsd:double<http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#double>, xsd:hexBinary<http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#hexBinary>, xsd:base64Binary<http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#base64Binary>,  xsd:integer<http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#integer>, xsd:nonPositiveInteger<http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#nonPositiveInteger>, xsd:negativeInteger<http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#negativeInteger>, xsd:long<http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#long>, xsd:int<http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#int>, xsd:short<http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#short>, xsd:byte<http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#byte>, xsd:nonNegativeInteger<http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#nonNegativeInteger>, xsd:unsignedLong<http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#unsignedLong>, xsd:unsignedInt<http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#unsignedInt>, xsd:unsignedShort<http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#unsignedShort>, xsd:unsignedByte<http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#unsignedByte>, xsd:positiveInteger",<http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#positiveInteger>

E61 Timeprimitive could be completely replaced by xsd:dateTime, without causing incompatibilities if more precision/ coverage would be needed.

"Spaceprimitive" should be a WKT string, I think.

Should E62 be xsd:string, or would that cause another outcry to be too complex?

If someone does not convert values into xsd, is that "incompatible"?

Best,



Martin






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