characters/states and measurements and other hoary problems
Stuart G. Poss
Stuart.Poss at USM.EDU
Thu Aug 3 12:52:43 CEST 2000
A couple of points.
With regard to footnote 1.
1 Attribution and sources for an item datum overides that for a character or
taxon, which override that for the treatment as a whole. Attribution for
characters and taxa are equivalent and additive.
Don't we also need to say that item data attribution at the specimen level
may override that for a character or taxon as a whole? Otherwise, the system
has no way of dealing with misidentifications, particularly if some but not
all parts have been associated with the wrong ID, as might be frequently
encountered in fossils, or when dealing with taxa whose character state
definitions are later found applicable for only a specific size range (ie
differentially break down at small sizes). Specimen or parts level
data/attributions also would presumably be additive, even if potentially
contradictory (subject to differences of opinion), would they not?
One file will comprise one treatment, the basic unit of which is one or more
characters describing one or more taxa or individuals.
If we are to presume nested levels of groupings of descriptor elements, then
we need to be able to clearly distinguish data values that are regarded as
referring to "individual units" (specimen, species, higher level taxon) at
one level, but are "collective" when evaluated at a different level. Not
only with the "collation rules" be different for different levels, but may be
different depending on whether a given feature (possibly "same feature but
defined differently") is regarded as a data item refering to a specific
"individual unit", or as a "collective unit". That is, the data item is a
representation of data that might apply to a collection, rather than a
measurable value that may have a scope no larger than a specific measure of a
specific specimen. Perhaps some treatments might include "collections of
collections" that would imply a mixing of both situations.
Seems to me we need a means of distinguishing between collective
representations and "unit values" (for lack of a better word), if for no
other reason than to be able to track which data items apply to particular
"features of general interest" (eg. leaves, roots, head, foot, etc) and which
taxa are involved (higher-level taxon, species, individuals, parts of
individuals). Its not clear to me how the current DDST can be used to
associate "basic units" that might be reasonably differentially defined at
different "levels of composition" by different investigators. Perhaps we
need some general means to assign the "scope" over which the definitions of
Kevin Thiele wrote:
> Dear List'eners
> attached find DDST Specifications.htm. See if this works.
> Cheers - k
> Name: DDST Specifications.htm
> DDST Specifications.htm Type: Hypertext Markup Language (text/html)
> Encoding: quoted-printable
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