Hmm, perhaps I had no good reason to assume that Event was being used as a shorthand for (Location, Time). I can see that there is a DwC:event implied by every occurrence record, even when that event is nowhere described. (And now I see that Rich thinks that Event does equal Location + Time, and further see that this could get wiry.)
But my objection isn't to Occurrence=(Individual, Event). I simply think that we're better off conceiving of occurrences as tuples, rather than defining them as intersections, or products, or whatever.
Joel.
On Thu, 28 Oct 2010, joel sachs wrote:
On Thu, 28 Oct 2010, Arlin Stoltzfus wrote:
On Oct 28, 2010, at 11:58 AM, joel sachs wrote:
Hey Rich, Hilmar, Paul, and everyone -
I liked the definition from a couple of weeks ago:
"An occurrence is a tuple consiting of time, place, individual, and some optional properties."
What's that lacking?
Nothing, but the form of "occurrence" as a 3-way relation between a thing, a place and a time might be less amenable to formal reasoning than some other formulations, depending on how its rendered.
It might be. But I haven't seen any examples of the kind of reasoning that the alternative definitions seek to enable. Did I miss them?
I thought that was the reason others had introduced "event" as place + time. Otherwise, what is the reason for "event"?
I was wondering the same thing. Event=(Location, Time) strikes me as weird, for a couple of reasons:
i. Intuitively, an event is something that happens at a region of space/time, not the region itself.
ii. More significantly, a DwC:event is a container for metadata that gets attached to occurrences via eventID. A DwC:event corresponds to the intuitive definition above, since you can have multiple DwC:events over the same space/time region, e.g. two groups surveying for different taxa, using different methodologies.
Joel.
Arlin
Arlin Stoltzfus (arlin@umd.edu) Fellow, IBBR; Adj. Assoc. Prof., UMCP; Research Biologist, NIST IBBR, 9600 Gudelsky Drive, Rockville, MD tel: 240 314 6208; web: www.molevol.org
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