[tdwg-content] Treatise on Occurrence, tokens, and basisOfRecord [SEC=UNCLASSIFIED]

[Blum, Stan]

This "three-way" was the essence of the definition used in the ASC model.

<copied text, from 
http://wiki.tdwg.org/twiki/bin/viewfile/TAG/HistoricalDocuments?rev=1;filena
me=Ascmodrpt.pdf 
page 24>

Entity Name: COLLECTING-EVENT (Supertype)
Description:
The act of collecting zero or more COLLECTING-UNITs at a particular LOCALITY
and TIME.

</copied text>

Other CollectingEvent properties discussed included the conceptual
equivalents of: CollectingMethod, Collectors (0-many), StatedDateTime, and
StatedLocality (=verbatimLocality).

Note that the zero-or-more cardinality on collecting-units (covering Roger's
observed absence) was discussed at some length and kept intentionally.
(I'll try to find John Damuth's very funny proposal to establish the
department of NULL collections at the Smithsonian.)  I think observations
were also discussed as a type of collecing-unit, but they weren't included
in the draft and I don't remember why.  Perhaps because the focus was on
collections, and observations would have expanded the scope too much to be
dealt with adequately.  Also, the model did not include in a structured way
was any measure of collecting (sampling) effort.  That would have been
relegated to text in a collecting method or collecting event remarks
(inadequate for quantifying abundance).

Back to the issue of event definition:  If Event is defined as just the
conjunction (association, intersection, join) of space and time, there is
nothing to tell you why this particular interval is of interest. From the
old school information modeling perspective, the definition should say WHAT
happened. In our biodiversity domain, it implies the act of trying to
collect or observe and that implies a collector/observer and something
collected/observed, including zeros.  I see Joel just posted support for
that notion.

And just to show that I'm not completely stuck in 1992, in the MVZ model --
a more detailed model for mammal, bird and herp collections, completed as
recently as 1996 -- recognized a distinction between the number (count) of
items observed and the number collected.

Our challenge is still to how to accumulate these artifacts of
conceptualization in an organized way, and to record how much support there
is for particular concepts.

Cheers,

-Stan


On 10/28/10 10:09 AM, "Arlin Stoltzfus" <arlin at umd.edu> 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.
> 
> I thought that was the reason others had introduced "event" as place +
> time.   Otherwise, what is the reason for "event"?
> 
> Arlin
> -------
> Arlin Stoltzfus (arlin at 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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