Development of the Environmental Application Reference Thesaurus (earth)

The paper addresses with the development of an environmental thesaurus in order to obtain an advanced tool for semantic control and knowledge organization to be applied to environmental information management. EARTh (Environmental Application Reference Thesaurus) was designed according to an approach to meaning representation that regards lexical meaning as a unitas multiplex, a unity that aggregates multiple traits organized according to a hierarchy. The thesaurus classification system comprises a vertical structure based on a limited set of categories, and is organized according to a tree semantic model. The tree structure analyses the meaning of the terms from a logical point of view. By placing each term in the classificatory-hierarchical structure, it aims to orientate the users toward the most essential characteristics of their semantics. The semantic analysis of terms is not limited to a static and univocal view. Each term is considered as a complex entity, where different layers of meaning are to be explored. The model envisages, in fact, the possibility of developing local arrangements of terminology, ensuring the openness and flexibility of the model, and allowing the representation of meaning according to different second-order perspectives. The implementation of an extended set of semantic relationships is also under way. The traditional thesaurus relationships will be arranged in a series of sub-relationships, whose semantic content is specified. In particular, the transversal relational structure that is based on associative relations will be strengthened, reinforcing the role of the thesaurus as semantic connector.