TDWG GIG Talking Points

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TDWG GIGTalking Points

• Phillip C. Dibner
• Ecosystem Associates

TDWG Annual Meeting Saint Louis, Missouri October
18, 2006
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The Observation and Measurements Spec

• The OM spec was developed in the context of the
  OGCs Web Services (OWS) initiatives
• General and firmly based in theory as well as
  application requirements
• Encoding-neutral (normative descriptions are in
  UML). (A GML serialization is available, but
  informative, not normative.)
• Current public version
• OGC doc 05-087r4
• On http//www.opengeospatial.org/standards/bp
• Further elucidation
• https//www.seegrid.csiro.au/twiki/bin/view/Xmml/O
  bservationsAndMeasurements

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The Observation Feature Type (OM)
Phenomenon
FoI
Observation
From Cox, 2005. OGC document 05-087r3_Observation
s_and_Measurements
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The Feature of Interest
Values for attributes of a real-world object or
phenomenon that is the subject of study (the
Feature of Interest) may be
1. Asserted the attribute is simply assigned a
value such as a sample number, experimenter,
institution, guid, etc.
2. Observed / Measured the value of the
attribute is an estimate derived from some
procedure. There is a well-defined conceptual
model for such values, built upon a strong
theoretical foundation.
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If our concepts are modeled as objects, they can
be incorporated into this observation model,
either naively or through more ambitious
analysis. E.g.
If the property we wish to measureis taxon,
then - the Feature of Interest may be a
(collection of) specimen(s), effectively a
DataSet (as defined in TCS) - the model for the
Phenomenon we are observing is surely addressed
by the vocabulary of TCS - (perhaps TaxonConcept
or TaxonName) - the codespace for the values of
the observed properties - the results - might be
the set of scientific names of some designation,
along with a reference to the author and
publication - an AccordingTo (per TCS)
If the observed property is collection or
observation location, then - the FoI is the
specimen (or the field occurrence of the
specimen) - the Phenomenon is geolocated
geometry - the result is an instance of such a
geometry
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Issue
We have more than one model for the same kind of
information. Will it be possible to combine data
from different services that respectively
provide, e.g., Darwin Core and ABCD? Can we
develop a single conceptual model with which
these and other TDWG data models - and external
models - are consistent? This is a generic
problem.
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A General Approachto Domain Modeling
(After R. Atkinson and S. Cox, at the TDWG GIG
Workshop in Edinburgh, June, 2006)

• Examine the domain and break up into subdomains
• If using UML, this is accomplished by
  grouping related objects into various UML
  packages. The packages can be distributed for
  others to use.
• 2. Decide what doesnt go in the domain of
  interest and belongs in someone elses.
• In UML, put in a placeholder or stub package,
  to be replaced later.
• 3. Identify the common elements that everyone
  agrees on, and that all implementations will
  include.
• 4. These form the basis of a conceptual model.

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Domain Modeling
(Atkinson and Cox)
5. Proceed to identifying points in question or
of disagreement. Clarify implications, explore
consequences for the model. The notion is that
here at least we can keep the model coherent. 6.
Develop or bring into the discourse
representational views that are of importance to
near-term or legacy implementations. These
represent the varied and sometimes incompatible
viewpoints that different implementors have of
the domain. Exercising these helps to clarify
the conceptual model. Methodology and tools for
mapping representational views to the conceptual
model and to each other are still very much under
development.
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Conceptual Modeling ExerciseTaxonomic Data
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Representational View ExerciseDarwin Core
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Some Conclusions

• Experimentation with domain modeling approach
  revealed some unanticipated aspects of our work.
  (In particular, the discovery of a new class -
  OrganismOccurrence - as the Feature of Interest
  whether for a field observation or a collection.)
  Its a valuable approach and we should explore
  it further.
• It is clear that TDWG is addressing many of the
  same, generic issues as other domain
  organizations.
• Problems have been solved by ISO TC 211 - whence
  come the 191xx documents - so TDWG doesnt have
  to. We should use them. This again should
  encourage us to think of our XML schema models as
  objects, and use the Object-property pattern.
• The real point of this address is simply that we
  should adopt the lessons of Object Oriented
  Design and Analysis - and continue to make use of
  the extensive body of work thats been done by
  collaborations of experts in domains outside our
  own. Cost a bit of pain, but well worth it.

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Acknowledgements