[Tdwg-obs] On observation definition / moving forward

tdwg at achapman.org tdwg at achapman.org
Thu Feb 9 23:09:47 CET 2006


Looking at the web site and thinking about definitions and terms - I am not entirely happy with the use of the term 'Negative data'.  In most of the areas I have been involved, the term 'Absence data' is more common and I think is more self explanatory (even though it is really implied absence rather than true absence in most cases).


Arthur D. Chapman

>>>From Steve Kelling <stk2 at cornell.edu> on 9 Feb 2006:

> Hello,
> I really like the improvements made on the definition, and I might
> suggest 
> that I put it up on the TDWG-obs website
> http://www.avianknowledge.net/tdwg.
> I think we still need to define occurrence, and I think that Arthur 
> Chapman's "species occurrence data" gets us most of the way there. My
> sense 
> is that the elaborations need to be expanded a bit more. For example,
> data 
> collection event.  I suggest that we include in the definition some 
> information about time, minimum required data, and so forth. These 
> definitions can be longer and more detailed than the observation 
> definition. So taking data collection event:  An event, during or after 
> which at least the minimum required data were recorded.
> Can we identify the minimum required data? For us it is:
> who the collector is
> where the information was collected (and should refer to occurrence 
> information and all of the discussion with it)
> when the data and time
> what was observed (and how many)
> effort distance covered, time spent etc.
> I'm sure there are other data for the minimum required data and this is 
> worth discussion.
> We should also discuss the event. For example, one of ours and Bird
> Studies 
> Canada projects (Project FeederWatch) the event can last 2 days.
> We also need to think about whether we want to include protocol. In our 
> definitions no protocol (incidental observation) is also a protocol.
> Anyway, thanks for the improvements on the definition of observation. I 
> (like Lynn) look forward to discussing some of these other issues.
> Steve
> At 05:03 PM 2/8/2006 -0500, you wrote:
> >With only comments from Bob & Arthur (thanks!), the latest version of
> >observation definitions is as follows:
> >
> >"An observation characterizes the evidence for the presence or absence
> >of an organism or set of organisms through a data collection event at a
> >location. Observations are not necessarily independent and could be
> >linked via characteristics such as time, place, protocol, and
> >co-occurring organisms."
> >
> >With the following draft elaborations for various terms (many thanks to
> >Bob Peet for providing most of these draft definitions):
> >
> >1) occurrence
> >
> >"Occurrence" has been changed to "evidence for the presence or
> absence".
> >
> >The key idea is that the organism or set of organisms was either
> >detected or not.  We also need to provide an opportunity for the
> >recorder to note the certainty.
> >
> >As an aside, recall we need to support minimalist protocols (e.g.
> >"organism/community (not)seen in field", "organism heard in field",
> >"scat seen in field", "tracks seen in field", "museum collection".)
> >
> >2) data collection event
> >
> >An event, during or after which at least the minimum required data were
> >recorded.
> >
> >3) location
> >
> >Ideally, at least geocoordinates plus an accuracy term. Since there is
> a
> >considerable amount of historical / legacy data that does not presently
> >have a georeference yet has valuable information that should be
> included
> >in observation databases and shared, we cannot at this time require
> data
> >to be in a GIS format.
> >
> >I (Lynn) suggest:
> >(a) Location information be required, preferably geocoordinates and
> >mapping precision, but if not available then a text description and the
> >finest level of geolocation using the Darwin Core attributes.
> >
> >(b) Location data include the representation of observations as point,
> >line, or polygon data (with the necessary spatial metadata).
> >
> >4) entity
> >
> >Dropped from the definition of observation.
> >
> >5) could be linked
> >
> >Can have a pointer or pointers to other observations, thereby creating
> >aggregate observations.  Note that commonality of date, time, place,
> >etc. is not sufficient in that the none of the observation authors
> >explicitly made the connection
> >
> >
> >Please share your comments / thoughts on all of the above definitions
> >with this email list.
> >
> >If people are generally comfortable with the above as working
> >defintions, then I'd like to propose that we move into the fun part of
> >identifying attributes to be developed into a schema.

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