[tdwg-tag] "Class" attribute in DwC

Steve Baskauf steve.baskauf at vanderbilt.edu
Sat Aug 8 14:46:54 CEST 2015

I think that this has been left intentionally vague because at this 
point we don't have well-defined relationships among Darwin Core 
classes.  It seems to me that placing the class terms on the same line 
are a clue that they are somehow related, but it isn't apparent to me 
that the subsequent terms are always special cases of the left-most 
terms.  I can provide an example where a LivingSpecimen isn't a 
MaterialSample because it was never collected.  I can also imagine Event 
instances which include many HumanObservations (i.e. Event serves to 
group observations, not to serve as a superclass for observations). 

There have been various attempts to lay out how the Darwin Core classes 
are related to each other.  But I'm not aware that there has ever been a 
consensus on it.  That's why the RDF Guide didn't touch the issue.  We 
were afraid that the guide would never be finished if we took up that 

I think it would be an excellent exercise to try to lay out how Darwin 
Core classes are related to each other.  But first, I would suggest that 
we lay out the use cases that we intend to satisfy by nailing down those 
relationships, then show how establishing those relationships help us.  
For example, I could suggest that we establish that

dwc:HumanObservation rdfs:subClassOf dwc:Event.

But what would I gain by doing that?  What would it prevent me from doing?

Bob Morris wrote:
> The current DwC Terms [1]   (carrying Identifier
> http://rs.tdwg.org/dwc/2015-03-19/terms/ and Date Modified: 2015-06-02
> ) is confusing  (confused? silent? ) about the relation of the "sister
> classes" to the terms intended (?) to be used therewith.  For example,
> dwc:Event, dwc:MachineObservation, and dwc:HumanObservation could
> reasonably(?) all have dwc:eventDate applied to them. But
> http://rs.tdwg.org/dwc/terms/index.htm#eventDatesuggests
> Class=dwc:Event.
> Now it's human-clear that for each of the "multiple" boldface lines in
> the index, the second and subsequent terms are meant to be special
> cases of the left most one. What I can't see is whether [1] intends to
> encourage (require?) this in some explicit way, and where that
> explicit way is to be found.  (I had a dream that the DwC RDF Guide
> might take a position....) .
> Thanks.
> --Bob
> p.s. I concede that some answers might lurk in the ongoing move of
> resources to http://tdwg.github.io/dwc/terms/.  My second dream was
> that tdwg.github.io does Content Negotiation and curl would rescue
> me....
> [1] http://rs.tdwg.org/dwc/terms/index.htm

Steven J. Baskauf, Ph.D., Senior Lecturer
Vanderbilt University Dept. of Biological Sciences

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