Hello
We are designing XML vocabularies for the description of biological species. See : http://jmvanel.free.fr and Taxonomic Databases Working Group - Structure of Descriptive Data TDWG-SDD@USOBI.ORG (mailing list) archive available at http://usobi.org/archives/tdwg-sdd.html
This is a large project: 250 000 species of plants, 1 000 000 of insects, relations beetwen plants and insects, etc...
There is a containment hierarchy (e. g. a flower contains petals) which raises no problems in XML.
But there is an inheritance hierarchy that I don't know how to handle using W3C's specifications alone. A genus has properties values (e. g. flower/petals/color = 'white' ) that MUST be inherited by the species in this genus. The properties values of a genus CAN be overriden by some species in this genus.
It seems that the "refines" property in XML Schema would bring the desired semantics, together with the "Schema Information Set Contribution: augmentations to instance information sets which follow as
a consequence of schema-validation". But the uncomplete state of the W3C document makes me unshure.
Although RDF and RDF Schema's data model are very promising, allowing to : - make links between plants and insects, - state properties about properties (some are morphological, others are chemical, etc ...) ,
I don't see anything clearly specified in RDF and RDF Schema for inheritance of properties.
Would this be a solution: - each instance of genus is a rdfs:Class, e.g. all daisies belong to (are rdfs:subClassOf) the genus Chrysantemum; - a genus has Class properties, - a species, instance of species, and subClassOf a genus, redefines some of the genus' properties, overrides the other properties, and adds properties unspecified by the genus.
Sample RDFS:
<rdfs:Class ID="Chrysantemum"/> <rdfs:subClassOf rdf:resource="http:botany.org/taxonomy#genus"/> <flower><petals> <color>white</color> <number>10--40</number> </petals></flower> </rdfs:Class>
<species> <rdfs:subClassOf rdf:resource="Chrysantemum" /> <name>maximum</name> <flower><petals><color>yellow</color> <!-- here do we inherit from <number> of Chrysantemum? --> </petals></flower> </species>
Info. for computer men: biology has a hierarchic classification of species whose 4 lowest levels are: order family genus species