- Adding metadata and using it from a program works…
 - … provided the program knows what terms to use!
 - We used terms like:
					   
Chart,LabelledBy,IsAnchor, ...- 
              
ChartType,GraphicsType, ... - etc
 
 - Are they all known? Are they all correct?
 - It is a bit like defining record types for a database
 - This is where RDF Schemas come in
					
- officially: “RDF Vocabulary Description Language”