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

[tdwg at achapman.org]

Seems we are on the same page, Robert

At the moment, I am preparing (for the BioGeomancer project) a document oin "Best Practices for Georeferencing" which will discuss in detail how to calculate Uncertainty.  At the moment, we are using a Point Radius Method (hence the Darwin Core element), but this is likely to move to footprinting in the future.  Also be aware, that the Geospatial Elements are being removed from Darwin Core 2, to be obtained via an Extension related to GML.  These will still include Uncertainty Elements.

Cheers

Arthur D. Chapman

>>>From "Robert K. Peet" <peet at unc.edu> on 9 Feb 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 
> CoordinateUncertaintyInMeters.
> 
> >
> > 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.
> 
> Bob
> 
>   ======================================================================
>       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
>                     http://www.unc.edu/depts/ecology/
>                   http://www.bio.unc.edu/faculty/peet/
>   ======================================================================
> 
> 
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