Are you sure, that RDF scheme could be generate on fly for big data. Probably could be, if you are building links among spatial and non spatial objects. But how, in the case, that you would like establish ling among spatial objects or objects with spatial references. And how to do this, when data are stored on different servers.

For example, I am working cross Europe and I am planning my trip from Czech to Spain, and I am searching for some natural or cultural heritage objects, which could be distributed on many local servers.