Knowledge representation in the semantic web for Earth and environmental terminology (SWEET)

The semantic web for Earth and environmental terminology (SWEET) is an investigation in improving discovery and use of Earth science data, through software understanding of the semantics of web resources. Semantic understanding is enabled through the use of ontologies, or formal representations of technical concepts and their interrelations in a form that supports domain knowledge. The ultimate vision of the semantic web consists of web pages with XML namespace tags around terms, enabling search tools to ascertain their meanings by following the link to the defining ontologies. Such a scenario both reduces the number of false hits (where a search returns alternative, unintended meanings of a term) and increases the number of successful hits (where searcher and information provider have a syntax mismatch of the same concept). For SWEET, we developed a collection of ontologies using the web ontology language (OWL) that include both orthogonal concepts (space, time, Earth realms, physical quantities, etc.) and integrative science knowledge concepts (phenomena, events, etc.). This paper describes the development of a knowledge space for Earth system science and related concepts (such as data properties). Some of the ontology contents are “virtual” by means of an OWL wrapper associated with terms in large external databases (including gazetteers and Earthquake databases). We developed a search tool that finds alternative search terms (based on the semantics) and redirects the expanded set of terms to a search engine.