Mauro
The proposition I think is that (at some level) it is desirable to transfer data between formats (such as DELTA, NEXUS or LUCID). If this is the case then there are difficulties that need addressing, specifically the loss of information that occurs. To some extent the different formats do deal with different subsets of 'descriptive' information, for example you might argue that characters used in phylogenetic analysis are defined differently from those used in identification programs. Nevertheless, there are still areas of overlap between two or more of the exisiting standards that are not currently supported by the available import/export routines (eg. character dependencies to name one).
The approach of amalgamating (what some might regard as) the 'proprietary' formats into a single 'superstandard' wasn't much favoured since that would only provide only for exisiting functionality. What was talked about at the TDWG meeting was to take a step back from existing standards in order to look at the whole area of descriptive data in the broadest sense (and for my money that includes marking-up or tagging of descriptive texts). As Gregor has already summarised elsewhere, the first step of the discussion should be a requirement analysis, the second the possible use of XML as a metaformat.
On the subject of the latter, XDELTA looks to me to be a straight representation of (a subset of) the DELTA standard in XML. While this does open up the scope for parsing, it isn't necessarily the approach I was thinking of.
For example, how could retrieval of descriptive information across a department or institution be facilitated? Is it because of the sheer flexibility in how the characters can be defined using DELTA, that querying across projects is difficult to say the least, unless the character set is global that is (and therefore with a lot of redundacy)?
Can character definitions be constrained without making too tight a straight-jacket for oneself? Might it be possible to represent taxon character descriptors by for example an entity/property/value (eg. leaf/shape/ovate) based schema? This on the face of it would seem to map onto an XML element/attribute/value schema pretty well. Would that help define more closely how we construct characters and maybe even prove universally applicable for all character types?
Could one constrain further by expressing within the schema the hierarchical relationships between the elements(eg 'blade' and 'petiole' as child elements of leaf') or would the introduction of terminology into the 'standard' be a step too far?
don
Dr Don Kirkup Herbarium RBG Kew
Dear Computer Taxonomists,
Greetings, and welcome to the new discussion list...
As an attempt to start a discussion, I am posting this to ask: do we all really agree that there should be a new standard for descriptive data based on XML, as a substitute for DELTA (as well as NEXUS and XDF)? Or should we instead just try to improve one of the existing formats? As of myself, when I first read the specifications of "XDELTA", I was under the impression that in some way the DELTA format as we know it would then become obsolete... But what of NEXUS, or XDF? Has anyone considered of the integration of these formats plus DELTA into a single new, XML-based, format for descriptive data?
Just "food for thought"...
Best wishes,
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- - - - - - - - Mauro J. Cavalcanti - - - - - - - - - - - - +
| Setor de Paleovertebrados, Departamento de Geologia e Paleontologia | | Museu Nacional do Rio de Janeiro | | Quinta da Boa Vista, 20940-040, Rio de Janeiro, RJ, BRASIL | | E-mail: maurobio@acd.ufrj.br | | Home Page: http://read.at/digitax/personal.html |
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