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Re: Ordering concepts in a Tree display

From: Jakob Voss <jakob.voss@gbv.de>
Date: Thu, 20 Jan 2011 16:05:43 +0100
Message-ID: <4D384F47.1070501@gbv.de>
CC: SKOS <public-esw-thes@w3.org>
Christophe Dupriez wrote:

> Saying that SKOS display is not SKOS business sounds strange to me: If I
> want "pure" "unhuman" data, I go toward SQL, XML or OWL.
> If I want "human consumable data", I go toward SKOS, HTML (or SGML!).

SKOS is as "unhuman" as SQL, XML, OWL, and SGML. As I understand 
Alistair, ordering was not considered as main issue of SKOS, just like 
other topics.

> Please let an ol'timer say that being able to associate a simple
> numerical value to a Concept to improve sorting in trees (local sort)
> has proven enough in practice for all applications I met.

That's a helpful statement. My idea of a Collation ontology allows to 
choose any property as sort key (also skos:prefLabel for alphabetical 
sorting, if we could agree on what alphabetical sorting means). But we 
could also just add a "ex:sortKey" propery.

> In theory, it would be better to add this value to the Broader relation
> (Narrowers are generally deducted from broaders). Going further than a
 > simple value linked to concepts can be justified by theoretical examples
 > but probably only very rare examples from "production-level" systems.

Let's better not get too complex.

> I propose to go further with the simple solution in a "community
> extension" to SKOS (I wrote you separately about this).
> Additional property "sortKey" to Concept.

There remains the problem of concepts, that exist in multiple concepts 
schemes. I'd prefer not to have one universal sort key, but to link the
sort key property to one concept scheme:

<my> a skos:ConceptScheme
   ex:sortBy <my:key> .

<your> a skos:ConceptScheme
   ex:sortBy <your:customProperty> .

<x> a skos:Concept ;
   <my:key> 2;
   <your:customProperty> 5;

If your notations are numerical, you can just say

<my> a skos:ConceptScheme
   ex:sortBy <skos:notation> .

 > If numerical XSD type, numerical sort; if alphabetical: alphabetical
 > sort; if other ordered data type: sort along that data type.

Sure data types could help to sort, but I don't understand how to apply 
this in practice. There is also the problem of what defines 
"alphabetical". Unicode collation? Unicode character codes? Locale settings?

> Label in the user language are then used as a second sort key (and as a
> primary one when there is no sortKey for the Concept).

There is no concept of "user language" in SKOS. There are just labels 
with languages, all equal.

> Idea: the sortKey could also be a reference to an orderedCollection:
> this would mean, if you need to sort this Concept, use its place in this
> orderedCollection (and not another as a Concept can be in many collections)
> Have a very nice day!


Jakob Vo▀ <jakob.voss@gbv.de>, skype: nichtich
Verbundzentrale des GBV (VZG) / Common Library Network
Platz der Goettinger Sieben 1, 37073 G÷ttingen, Germany
+49 (0)551 39-10242, http://www.gbv.de
Received on Thursday, 20 January 2011 15:06:16 UTC

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