What is the Subset Schema Generation Tool (SSGT)?
The Department of Justice funded the Georgia Tech Research Institute (GTRI) to build a Subset Schema Generation Tool (SSGT) that would allow searching the GJXDM and creating customized subsets. A similar tool exists for NIEM.
These tools present the full set of GJXDM and NIEM types and elements for the user to select into a subset. Components can be added to the subset by performing searches for the specific types or elements that are required. Once selected, types and elements are included in the subset. Types and elements erroneously included in the subset can be removed as desired.
Once the desired subset is built, the user can generate the schema subset (which is in fact often a set of related schemas).
SSGT Tutorial: http://vimeo.com/109940669