Types of data
Jim Croft
jrc at ANBG.GOV.AU
Fri Nov 26 05:51:54 CET 1999
>Surely
>the way you measure an attribute depends on what you are going to use the
>measurements for, ultimately that's a question of precision. If there is a
>possibility that there will be a variety of uses (reuse) for the data, then
>an indictation of the degree of precision of the measurement would be highly
>desirable.
Source and precision stuff is surely important, but it is quite possible to
end up with major bloat and more meta than meaningful data. This may not
be a problem but there is certainly a practical limit as to how far we can
or should go in this direction.
>Isn't it also important to distinguish whether the description refers to an
>actual leaf (ie. that leaf there, on that specimen is ovate) or whether you
>are making a generalisation about a taxon (ie leaves ovate to obovate)?
Most certainly. I must admit I thought we were talking about taxon
descriptive data, but therie is probalby no reason at all why the same
principles and data structure/definitions can not be used forthe
structures/features themselves.
>A taxon cannot have a leaf shape, only leaves can, and an actual leaf does
not
>usually vary in shape except through time.
Conversely, only a taxon can have, or not have, ovate leaves. Is this a
generalization or a fact? (and does it matter?)
><my_taxon_description>
> <specimen>
> <leaf shape="ovate" length_mm="10"/>
> <leaf shape="ovate" length_mm="8"/>
> <leaf shape="obovate" length_mm="25"/>
> </specimen>
> <specimen>
> <leaf shape="ovate" length_mm="5"/>
> <leaf shape="obovate" length_mm="31"/>
> </specimen>
></my_taxon_description>
Conceptually I like this reperesentation - it is what we all do and may or
may not write down. But as you say, maybe people want to know this, maybe
they don't...
jim
__________________________________________________________________________
Jim Croft ~ jrc at anbg.gov.au ~ http://www.anbg.gov.au/people/croft.jim.html
ph 02-6246-5500 ~ fx 02-6246-5248 ~ GPO Box 1600 Canberra ACT 2601
More information about the tdwg-content
mailing list