Special states (2)

Kevin Thiele kevin.thiele at BIGPOND.COM
Fri Mar 21 10:44:01 CET 2003

Comment on Gregor's Special States document.

Gregor writes: "All these special states apply to entire characters. SDD
currently provides no mechanism to express partial knowledge within a
character (e. g. to score one state as not applicable, but another as
present). Theoretically it is possible that a character is only partly
entered, but this is not likely in a well designed terminology (it does
happen where character clusters are combined into pseudo-characters, but
such a design is considered problematic)."

Not so. One important difference between Lucid and DELTA is that DELTA can
only encode uncertainty for a whole character, Lucid only for a character
state. Often in Lucid we do encode uncertainty for an entire character (for
example, fruit colour is uncertain for a given taxon because fruits are
unknown) - we do this by (slightly messily) encoding uncertainty for all the
states of the character:

Fruit colour (coding for taxon x)
    red - UNCERTAIN
    yellow - UNCERTAIN
    pink - UNCERTAIN
    white - UNCERTAIN

In other circumstances, we encode certainty data for some states of a
character, uncertain for others:

Distribution by States within Australia (coding for taxon x)
    Victoria - ABSENT
    New South Wales - PRESENT
    Queensland - PRESENT
    Northern Territory -UNCERTAIN
    Western Australia - PRESENT
    South Australia -ABSENT
    Tasmania -ABSENT

This is real coding for a taxon that has been collected in rainforests in
northern New South Wales, Queensland and Western Australia. It has not been
recorded in the Northern Territory, although suitable rainforests occur
there and it may well be found there. I'm confident that it does not occur
in the other states.

Cheers - k

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