Types of data

Kevin Thiele kevin.thiele at PI.CSIRO.AU
Thu Nov 25 15:53:24 CET 1999

Leigh Dodds writes:

>> I too would argue that what we seek is a system that distinguishes between
>> "observations", measured in some sense (either directly using
>> some device), or perhaps "mapped" using known or widely used conventions
>> higher level abstractions that often pass as qualitative "data", (ie leaf
>> "ovate" or state "relatively derived" or "1").
>Would it be too simplistic to simply allow the format to express
>the source (qualitative/quantitative, or a more detailed description)
>or a particular data set?

Too simplistic, I think. There will surely be many cases where in one data
set some characters will be "real" (i.e. low-level) observations while
others will be abstractions. For instance, sometimes it will be viewed as
worthwhile for the taxonomist to capture real data (leaf shapes are fairly
easy to do), other times anything other than abstraction is practically
impossible (try working out how to capture indumentum characteristics

More on the entity/property/value model. Don wrote:

>Can character definitions be constrained without making too tight a
>straight-jacket for oneself? Might it be possible to represent taxon
>character descriptors by for example an entity/property/value (eg.
>leaf/shape/ovate) based schema?
>This on the face of it would seem to map onto an XML element/attribute/value
>schema pretty well. Would that help define more closely how we construct
>characters and maybe even prove universally applicable for all character
>Could one constrain further by expressing within the schema the hierarchical
>relationships between the elements(eg 'blade' and 'petiole' as child
>elements of leaf') or would the introduction of terminology into the
>'standard' be a step too far?

This worries me.  Is the entity/property/value schema restricted to 3
levels? (ditto for XMLs element/attribute/value). If so, it seems too much
of a straightjacket, especially if we want to express a hierarchy of
elements like this. What to do about
I agree that a hierarchically structured schema may be wonderful, but in a
biological context I wouldn't like to see it constrained at 3 levels just
because that's what existing computer formats do.

Cheers - k

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