It sounds like perhaps now is the time to focus on the ontological relationships among classes, as the next major focus of DwC advancement. I would NOT regard "HumanObservaton" as a subclass of "Event". I believe that "Event" should be kept clean as fundamentally an intersection between a Location instance and a point in time. After much thinking and testing on this, we've finally come to the conclusion in our data models that "Location" is defined by two of the four space-time dimensions (X & Y; effectively represented as Geocoordinates -- whether as a point, Point/radius, track, polygon, etc.), and "Event" is defined by one Location instance plus the other two space-time dimensions (Z & T; effectively represented as elevation, depth and date/time). I'd be happy to explain why we came to this conclusion, but that's another thread. The point is that I think "Event" should remain as an abstract four-dimensional address, created as an instance to capture space-time information for something else. In DwC, that "something else" is an Occurrence. Within the confines of existing DwC, "HumanObservation" comkes closes to being a subclass of Occurrence. However, there is still one missing class that I believe we need to complete the core ontology space of DwC -- which is what we refer to as "Evidence", and Darwin-SW refers to as "Token" (https://code.google.com/p/darwin-sw/). Our model draws the lines slightly differently from the diagram for D-SW, but in general they represent a convergence of thinking on the relationships among DwC classes. In answer to Steve's question:
dwc:HumanObservation rdfs:subClassOf dwc:[Occurrence]
But what would I gain by doing that? What would it prevent me from doing?
-----Original Message----- From: tdwg-tag-bounces@lists.tdwg.org [mailto:tdwg-tag- bounces@lists.tdwg.org] On Behalf Of Steve Baskauf Sent: Saturday, August 08, 2015 2:47 AM To: Bob Morris Cc: tdwg-tag@tdwg.org Subject: Re: [tdwg-tag] "Class" attribute in DwC
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
guide would never be finished if we took up that subject.
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,
I'm not technically savvy enough to answer that question from an implementation perspective; but from a DwC comprehension perspective, it moves us a step closer to mutual understanding of how to transform DwC content into a functional data model. We all kinda/sorta know that already, but as evidenced by the different perspectives of "HumanObservation as a subclass of Event" vs. "HumanObservation as a subclass of Occurrence" just now revealed & expressed, it probably wouldn't hurt to be more explicit about these sorts of things in DwC documentation. that the 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? Steve
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....
-- Steven J. Baskauf, Ph.D., Senior Lecturer Vanderbilt University Dept. of Biological Sciences
postal mail address: PMB 351634 Nashville, TN 37235-1634, U.S.A.
delivery address: 2125 Stevenson Center 1161 21st Ave., S. Nashville, TN 37235
office: 2128 Stevenson Center phone: (615) 343-4582, fax: (615) 322-4942 If you fax, please phone or email so that I will know to look for it. http://bioimages.vanderbilt.edu http://vanderbilt.edu/trees
_______________________________________________ tdwg-tag mailing list tdwg-tag@lists.tdwg.org http://lists.tdwg.org/mailman/listinfo/tdwg-tag