It seems to me that there is an underlying issue that makes some of the DwC typing mechanisms difficult to apply to multimedia---at least in the breadth the MRTG means to approach it--is that DwC is heavily slanted towards documenting organisms as opposed to documenting descriptions. Gregor's (and my) favorite examples are pictures meant to illustrate a character and its states. It's possible, but likely pointless, to document a picture such as http://bit.ly/pottedTomato as only, or even primarily, something about the particular organism photographed. The photograph was (speculatively) taken to illustrate the concept of compound leaf for use in the Morphster ontobrowser. Even if its original purpose \were/ to document, say, an Occurrence, MRTG attempts to provide assistance in determining, without fetching the media, a resource's fitness-for-use for some use perhaps unknown or of no interest to the originator of the image. To support this, a third-party might be motivated to create a MRTG or even a DwC record as an annotation of the original resource record. Such a new record must sometimes not be bound by any semantics that tie it to that particular potted tomato plant, or the time and place the picture was taken.
This particular example might be addressed by adding, e.g. CharacterIllustration, to the DwC-specific basis of record vocabulary. That might be a good idea, but it does not fully address my worry, which is how scalable is DwC to concerns wider than documenting occurrences. Even if such scalability is to be principally the addition of recordClass terms for specific uses, it would be good if one can examine whether such extensions have unintended consequences.
Unbridled class extension has a dark side: it's easy to introduce inconsistencies and circularities.
Bob Morris
On Fri, Oct 23, 2009 at 4:20 PM, John R. WIECZOREK tuco@berkeley.edu wrote:
Gregor,
That sounds like a good solution to all of the problems. I would propose that the basisOfRecord IS the the same thing as your proposed dwc:subtype, so we should keep basisOfRecord.
Net solution:
- keep dcterms:type
- use DCType vocabulary to control dcterms:type (so, StillImage,
PhysicalObject, Event, etc.) 3) keep basisOfRecord 4) use our DwC-specific subtypes (PreservedSpecimen, FossilSpecimen, HumanObservation, etc.) as the controlled vocabulary for basisOfRecord without a formal type vocabulary (very close to how it is now, just some of the terms would go to dcterms:type). 5) add a recordClass term 6) use the DwCType vocabulary to control the recordClass term instead of the dcterms:type term.
This solutions fixes the Dublin Core - Darwin Core controlled vocabulary problem, retains all existing terms, isolates the controlled vocabulary that is specific to our domain, making it very easy to expand without changes to the standard.
Any objections?
John
On Fri, Oct 23, 2009 at 12:33 PM, Gregor Hagedorn g.m.hagedorn@gmail.com wrote:
How about we retain basisOfRecord, but have it refine dcterms:type, drop dcterms:type and add a "recordClass" term in its place that is governed exactly as dcterms:type is currently being used in the recently ratified version of the Core?
recordClass for Taxon/Occurrence/Event sounds good.
I am less sure about keeping the "perspective-dependent" basisOfRecord-term in a place where dcterms:type. The dcterms:type vocabulary is, in principle, extensible, and meant to be extended. Except, of course, some specific xml-implementation of dublin core prevent this... To avoid problems with this one might desire to have only the strict resource type vocabulary in dcterms:type. Then this could by PhysicalObject/Event and a dwc:subtype added to express PreservedSpecimen/MachineObservation etc. Essentially, MRTG intends to use such a mrtg:subtype as well to differentiate different StillImage or Text subtypes: http://www.keytonature.eu/wiki/MRTG_Schema_v0.8#Subtype
This would then mean, DarwinCore might support: dwc:recordClass dcterms:type dwc:subtype
Gregor