- From: Jonas Liljegren <jonas@paranormal.o.se>
- Date: Sat, 18 Dec 1999 22:18:31 +0100
- To: rlake@galdosinc.com, RDF Intrest Group <www-rdf-interest@w3.org>
Ron Lake wrote: > > 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. As I understand it; if a property has LinearStrings as its range, it can also be a container with LinearStrings. The type of container can't be specified in the schema specification. Some rules have to be stated outside RDF. > 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: With my changes. Properties starts with lower case. Classes starts with upper case. Just for clarity. It could be something like this... <rdf:Property id = "cList"> <rdfs:range resource = "rdfs:Literal"/> <rdfs:domain resource = "#CList"/> </rdf:Property> <rdfs:Class id="CList"> <rdfs:label>CList</rdfs:label> <rdfs:comment>CList is a list of coordinate tuples. Coordinates in the tuple are separated commas. Tuples are separated by whitespace</rdfs:comment> </rdfs:Class> <rdf:Property id = "lineString"> <rdfs:range resource = "#CList"/> <rdfs:domain resource = "#LineString"/> </rdf:Property> <rdfs:Class id="LineString"> <rdsf:subClassOf resource = "Geometry"/>< <rdfs:label>LineString</rdfs:label> <rdfs:comment>Line string is a piecewise linear curve defined by an asscoiated CList</rdfs:comment> /rdfs:Class> <rdf:Property id = "polygon"> <rdfs:range resource = "#LineString"/> <rdfs:domain resource = "Polygon"/> </rdf:Property> <rdfs:Class id="Polygon"> <rdfs:subClassOf resource = "#Geometry"/> <rdfs:label>Polygon</rdfs:label> </rdfs:Class> Polygon --polygon--> LineString --lineString--> CList --cList--> Literal And with Sequences: Polygon --polygon--> Seq --_1--> LineString --_2--> --_3--> --lineString--> Seq --_1--> CList --cList--> Seq --_1--> Literal --_2--> --_2--> --_3--> --_3--> But I havent given any thought about how this is going to be used, since I don't entierly understand your comments. But I think that the names should be changed. -- / Jonas - http://paranormal.o.se/perl/proj/rdf/schema_editor/
Received on Saturday, 18 December 1999 16:18:57 UTC