Understanding Thematic Mapping

Thematic mapping automatically extracts key terms (nouns or noun phrases) contained in a set of documents and organizes them in a hierarchy—a concept tree. Concept trees provide:

Easy visualization of subject areas in the document set


Document search based on key concepts in the document set


An automatic (or semi-automatic) method of creating and populating a taxonomy


Thematic mapping discovers contextual concepts (terms that are contextually related based on their distributional patterns in the document set). These contextual concepts might not match the domain-level concepts the user has in mind. Also, thematic mapping only generates one possible concept hierarchy out of the many possible concept hierarchies for the document set. The concept hierarchy generated might not completely match the one that the user has in mind.