Modelling collections in RDF/Schema

Hi,

I am involved in the development of a specification for encoding spatial
information in XML which has now reached public RFC status in the OGC
(OpenGIS Consortium). I think we could make good use of RDF/S to model
our spatial information. I have looked at the RDFMS and RDFS
specifications and have a few questions, perhaps you
could help me with:

  1. How do I model a collection of elements of a particular type ?  I
     would like to say for example that Polygon is a Property with a
     range which is a sequence of LinearStrings, but I have no
     restriction on the number of such strings.
  2. I would like to say that LinearString is a property whose range is
     a sequence of Coordinate Lists which are literals.
  3. I would also like to say that Polygon is a Class (actually a
     subclass of Geometry) as well as being a property.
  4. All of the Geometry types should be Properties of a Feature.

Here is a rough start:

<rdf:Property    id = "CList">
    <rdfs:label>CList</rdfs:label>
    <rdfs:comment>CList is a list of coordinate tuples.  Coordinates in
the tuple are separated by
                             commas.  Tuples are separated by whitespace
</rdfs:comment>
    <rdfs:range resource = " .....................#Literal"</rdfs:range>

</rdf:Property>

<rdf:Property id = "LineString">
    <rdfs:label>LineString</rdfs:label>
    <rdsf:subClassOf  resource = "     Geometry"  // reference to OGC
defined Geometry Class
    <rdfs:comment>Line string is a piecewise linear curve defined by an
asscoiated CList</rdfs:comment>
    <rdfs:range resource = "............"  //I want it take values in
the set of CLists !!!
</rdf:Property>

<rdf:Property id = "Polygon">
    <rdfs:subClassOf  resource = " ..... Geometry" // reference to OGC
defined Geometry Class
    <rdfs:label>Polygon</rdfs:label>
    <rdfs:range resource = "        "  // I want it to take values in
the set of LineStrings
</rdf:Property>


Your help would be greatly appreciated !!!


Cheers

Ron

rlake@galdosinc.com