G.Hagedorn at BBA.DE
Mon Dec 20 14:24:57 CET 1999
> As a first cut I just transferred everything from DELTA comments into
> XDELTA comments, although it was quite obvious that the 'comment'
> component of DELTA was overloaded depending on context (a legacy
> problem I guess, and one which raises the prospect of 'extensibility'
> as a requirement of the new format).
The concept of "overloading" is very good, I think it helps to understand
the issue. I believe in the new standard, we will want to have as little
overloading (which means context specific contents) as possible.
In general, all data elements should be defined much more exactly
than in Delta. Many things in Delta are really defined by result, not
by purpose, which means that comments may have a different function
in different applications (e.g. identification or nat. language
> DELTA already allows dependencies between characters - such
> that if a specific state has been selected for a character, other
> characters are ignored (i.e. no wings, ignore anything to do
> with wings). Is there any other dependency relationships that
> might be required, or additional information about such a
> Restricting states to particular options depending on the property
> in question (e.g. leaf and/or wing shape) leads back to the
> prior discussion on accepted standards for character description.
If I understand this correctly, it assumes that there would be a
general "property" entity. An instance of this entity would then be
the property "shape", which has a list of generally applicable
values. Some of these values would apply to leaves as well as to
butterfly wings, other may be more specific.
I wonder, whether terminology is actually well developed enough to
really support this notion. The discussion is somewhat similar to the
discussion on lexicons/globally applicable character definitions.
My feeling is, that nowhere ever has "shape" been defined in a way
that would be applicable to all areas. Defining dependency rules to
create overlapping, or partly matching sets of character state seems
to me a troublesome process.
Further, one should realize that we need more than a name for such
concepts. Two shapes in plants and butterfly wings that may be more
or less identical in concept may be named identical in one language,
but not in another.
I believe that properties are useful (and from the viewpoint of
information modeling are preferable to use), but dangerous to use in
reality, simply because we as biologists never did any globally
applicable terminology. Also, we have to make the concept clear to
any user, e.g. that if she or he changes the name of a state, this
change is actually applicable not only to his butterfly, but also to
the plant the collegue is working on in the same database (a bit
gross example, but more likely somewhere in a large institution for
two people working on separate orders, or perhaps on ferns and
Who thinks global state lists for something like shape (already
separated into 2D-shape, 3D-shape), texture, smell, color, are
possible and useful?
Gregor Hagedorn G.Hagedorn at bba.de
Institute for Plant Virology, Microbiology, and Biosafety
Federal Research Center for Agriculture and Forestry (BBA)
Koenigin-Luise-Str. 19 Tel: +49-30-8304-2220
14195 Berlin, Germany Fax: +49-30-8304-2203
Often wrong but never in doubt!
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