[Tdwg-obs] Tdwg-obs Digest, Vol 5, Issue 2

Robert K. Peet peet at unc.edu
Thu Feb 9 23:45:06 CET 2006

> From: "Lynn Kutner" <Lynn_Kutner at natureserve.org>

> "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."

I am happy with something close to this.

> 3) location
> 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).

I agree, however, I would like to include a measure of uncertainty.
Darwin Core has such an element, CoordinateUncertaintyInMeters, that would 
work. "The upper limit of the distance (in meters) from the given latitude 
and longitude describing a circle within which the whole of the described 
locality must lie. Use NULL where the uncertainty is unknown, cannot be 
estimated, or is not applicable."

> 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

Some revision along these lines would be helpful.

From: <tdwg at achapman.org>

> The word 'protocol'  what does this mean in this context?

> In your Locality definition a).  I don't think you mean Mapping 
> Precision here - it is only one aspect of accuracy/uncertainy.  Also - 
> not all coordinates will be attached to a map (e.g. GPS).  I prefer any 
> of the the terms 'Uncertainty', 'Accuracy' or 'Maximum Error' (or all 
> three/four with Precision).  They are all slightly different in meaning.

See my note above about the Darwin Core element 

> My other suggestion revolves around the mention of Darwin Core here - is 
> it necessary - some may be using ABCD, etc. and should we necessarily 
> have the definition tied to a protocol

We don't need to be tied to a standard, but the closer we come to being 
consistent with the rest of the community, the more likely our standard is 
to be widely accepted.  In short, I like following the Darwin Core where 
it works for us, but I see no need to explicitly refer to the Darwin Core. 
Neither the Darwin Core or ABCD will work for us when it come to taxonomic 
identification and there we will need to use the TDWG TCS schema.

> From: Hannu Saarenmaa <hsaarenmaa at gbif.org>
> "set of organisms" doesn't sound very natural to me. What about "group 
> of organisms"?  However, doesn't the second sentence covers this anyway?

"Set of", or "group of", or "assemblage of" all work for me.


      Robert K. Peet, Professor & Chair         Phone:  919-962-6942
      Curriculum in Ecology, CB#3275            Fax:    919-962-6930
      University of North Carolina              Cell:   919-368-4971
      Chapel Hill, NC  27599-3275  USA          Email:  peet at unc.edu

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