Since its launch in 1998 the thematic indexation of the Flemish Environmental Navigator is carried out manually by legal experts of the University of Ghent, Belgium. However, due to the exponential growth of legal documents a physical indexation process eventually was no longer tenable, nor desirable. Hence, a semi-automatic indexing tool for environmental legislation, called NAVDEX, was developed. A specific algorithm was determined, based On the presence of similar terms in law objects. A parameter was defined, reflecting the strength of the relation between law objects in order to computerise the return on a user's query. 1/7 view, of managing the relations between law objects, a visualisation tool was created in order to provide the legal experts with a detailed overview of all associated law Objects. The testing corpus was decided to be VLAREA, a Flemish order concerning waste prevention and management. The evaluation of the test results was carried out by experts in environmental legislation, who computed the relative recall of several search terms. With an average score of 0.63 NAVDEX is able to retrieve nearly two third of the associated law objects. Consequently the evaluators' conclusions were unanimous so as to define NAVDEX as a useful tool to determine and visualise associated LawObjects
