Visual reference for IMS RDF binding

A visual reference for the IMS RDF binding is attached. I created it as the
binding is defined by 10 separate schemas making it difficult to keep track
of which classes and properties come from which namespace.

Classes are represented as ovals, properties as arrows, and instances of
classes as rectangles attached to a class by a line. Properties domain and
range restrictions are displayed by their attachment to a class (ie. if the
arrow points to a class, the properties range is defined as being to that
class). Sub properties are indicated by grouping them together within a box,
headed by the property they are a sub property of.
Note that instances of the lom_edu:LearningResrouceType are also classes,
and are displayed as small ovals rather than as rectangles.

Looking at the sample RDF data on the IMS site it appears that there may be
missing elements from this set of schemas - a lom_gen:Catalogue is used in
http://www.imsglobal.org/rdf/RDF/vocab.rdf, but not defined within the
lom_gen namespace (or anywhere else in the schema).

John Gilbert.