Leigh wrote:

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 reporting).

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 relationship?

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 conifers).

Who thinks global state lists for something like shape (already separated into 2D-shape, 3D-shape), texture, smell, color, are possible and useful?

Gregor ---------------------------------------------------------- Gregor Hagedorn G.Hagedorn@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!