Quoting Owen Stephens <[log in to unmask]>:


>
> This is why RDA worries me - because it (seems to?) suggest that we  
> define a schema that stands alone from everything else and that is  
> used by the library community. I'd prefer to see the library  
> community adopting the best of what already exists and then  
> enhancing where the existing ontologies are lacking.

I've been ruminating a bit on the ad/dis-advantages of re-use vs.  
create your own then link to others. In the end, I wonder how easy it  
will be to manage a metadata scheme that has cherry-picked from  
existing ones, so something like:

dc:title
bibo:chapter
foaf:depiction

but NOT including all properties in those namespaces. It requires any  
application to have detailed knowledge about the particular selections  
made. On the other hand, something like:

myNS:title --> sameas --> dc:title
myNS:chapter --> sameas --> bibo:chapter
myNS:depiction --> sameas --> foaf:depiction

allows you to easily identify "your" properties, but at the same time  
gives you the equivalents to other properties in other namespaces for  
sharing. It also gives you greater stability. If the FOAF community  
should (rudely) change the meaning of depiction, you could find  
yourself using a property that no longer means what it should.  
Instead, if you have your own namespace you can change your link to  
foaf (or remove it altogether) to indicate that you now fork from that  
property.

Perhaps what I perceive is that properties persist over time and  
relationships can be more easily treated as relating to "now."

kc

p.s. I agree with you about RDA, but think that links could be made to  
remedy that.


> If we are going to have a (web of) linked data, then re-use of  
> ontologies and IDs is needed. For example in the work I did at the  
> Open University in the UK we ended up only a single property from a  
> specific library ontology (the draft ISBD  
> http://metadataregistry.org/schemaprop/show/id/1957.html "has place  
> of publication, production, distribution").
>
> I think it is interesting that many of the MARC->RDF mappings so far  
> have adopting many of the same ontologies (although no doubt partly  
> because there is a 'follow the leader' element to this - or at least  
> there was for me when looking at the transformation at the Open  
> University)
>
> Owen
>
> Owen Stephens
> Owen Stephens Consulting
> Web: http://www.ostephens.com
> Email: [log in to unmask]
> Telephone: 0121 288 6936
>
> On 5 Dec 2011, at 18:56, Jonathan Rochkind wrote:
>
>> On 12/5/2011 1:40 PM, Karen Coyle wrote:
>>>
>>> This brings up another point that I haven't fully grokked yet: the  
>>> use of MARC kept library data "consistent" across the many  
>>> thousands of libraries that had MARC-based systems.
>>
>> Well, only somewhat consistent, but, yeah.
>>
>>> What happens if we move to RDF without a standard? Can we rely on  
>>> linking to provide interoperability without that rigid consistency  
>>> of data models?
>>
>> Definitely not. I think this is a real issue.  There is no magic to  
>> "linking" or RDF that provides interoperability for free; it's all  
>> about the vocabularies/schemata -- whether in MARC or in anything  
>> else.   (Note different national/regional  library communities used  
>> different schemata in MARC, which made interoperability infeasible  
>> there. Some still do, although gradually people have moved to  
>> Marc21 precisely for this reason, even when Marc21 was less  
>> powerful than the MARC variant they started with).
>>
>> That is to say, if we just used MARC's own implicit vocabularies,  
>> but output them as RDF, sure, we'd still have consistency, although  
>> we wouldn't really _gain_ much.    On the other hand, if we switch  
>> to a new better vocabulary -- we've got to actually switch to a new  
>> better vocabulary.  If it's just "whatever anyone wants to use",  
>> we've made it VERY difficult to share data, which is something  
>> pretty darn important to us.
>>
>> Of course, the goal of the RDA process (or one of em) was to create  
>> a new schema for us to consistently use. That's the library  
>> community effort to maintain a common schema that is more powerful  
>> and flexible than MARC.  If people are using other things instead,  
>> apparently that failed, or at least has not yet succeeded.
>



-- 
Karen Coyle
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ph: 1-510-540-7596
m: 1-510-435-8234
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