Re: Relationships involving collections

On Tue, 5 Feb 2008 at 10:03:09, Alasdair Gray <agray@dcs.gla.ac.uk>
wrote
>With regard to the latest skos reference working draft, how should
>mappings between vocabularies that involve collections be performed?
>
>In the astronomy vocabularies that I have been working with, I have come
>across several instances where I either need to directly relate 2 collections
>or a collection with a concept. One such example is for relating the
>vocabulary of astronomy and astrophysics journal keywords (A&A) [1] with
>the international astronomical union thesaurus (IAUT) [2]. Below are brief
>snippets of the two vocabularies.
>
>A&A
>Concept: "Sources as function of wavelength"
> NT Collection: "Gamma Rays"
>   NT Concept: "Gamma ray bursts"
>      Concept: "Gamma ray observations"
>      Concept: "Gamma ray theory"
>
>IAUT
>Concept: "Radiation"
> NT Concept: "Gamma rays"
>
>I would like to assert
>A&A:"Gamma Rays" skos:exactMatch IAUT:"Gamma rays"
>
>In fact, as I have typed up this example I wonder if the A&A vocabulary
>snippet I have given is in fact valid in the new skos reference as is declares
>a collection to be a narrower term and this goes against the domain and
>range declarations for the BT/NT relationships.

Well, I don't know about SKOS, but the structures above do not conform
to the thesaurus standard BS8723-2. They should be something like this:


[A&A]
radiation sources
    (radiation sources by wavelength)
    NT  gamma radiation sources
        visible radiation sources
        microwave radiation sources

gamma radiation sources
    RT gamma rays

gamma radiation
    USE gamma rays

gamma rays
    NT  gamma ray bursts
    RT  gamma ray observations
        gamma radiation sources
        gamma ray theory

[IAUT]
radiation
    NT gamma rays

You have shown "Gamma rays" as "Collection", but I hope that nobody
would interpret it as that, in SKOS or elsewhere. It looks like an
ordinary concept, and doesn't become a "collection" just because it has
some narrower terms. As I understand it, "collection" is the SKOS term
for what the thesaurus standard BS8723-1 calls an "array": a group of
sibling terms. An array may be preceded by a node label showing a
"characteristic of division", e.g. (... by wavelength) in the above
example. Node labels are just interpolated explanatory labels; they do
not represent concepts and they do not have relationships.

You can't really make mappings between an array and a concept. If you
want to map the whole group, you should probably be mapping their parent
term. In this case the concept "gamma rays" occurs in both thesauri, and
as its definition is presumably the same in both there should be no
problem in making a direct mapping.

It looks as though the thesauri you are working with are not well
structured, having invalid NT relationships, so problems are inevitable.
:-(

Leonard Will

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Received on Tuesday, 5 February 2008 10:47:32 UTC