Enhancing interoperability in the GFZ ISDC ontology by embedding SKOS transformed NASA's GCMD keywords for describing and connecting entities and VIAF authority data for referencing personal and corporate names

First scientific results in the realm of Semantic Web based on cooperative educational and research activities between the Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences (GFZ) and the University of Applied Sciences Fachhochschule Potsdam (FHP), Faculty of Information Science are presented in this paper. The GFZ Potsdam runs the GFZ Information System and Data Center (ISDC) portal, which is the access point for all manner of geoscientific geodata, its corresponding metadata, scientific documentation and software tools. The majority of data and information are global satellite based or in-situ geomonitoring products such as geodetic data as well as geomagnetic and atmospheric data. The current technology behind the ISDC portal consists of hard disc archives for data products, relational databases for product related content data and data flow management information as well as conventional FTP and Web services as frontend for data retrieval and data access purposes. New user requirements concerning across domain integration and interoperability of science data and metadata as well as the availability of an applicable technology and appropriate tools in the realm of Semantic Web were the driving forces for the development of the ISDC ontology. Following NASA's GCMD standards the existing metadata have been structured and categorized in five main classes, four additional classes and diverse subclasses so far. The classes as well as associated object and data properties have been modeled using the ontology design tool Protégé. Individuals, which represent main parts of the ISDC data repository as well as use case based class constructs have been added to the model. Both, individuals and additional asserted logical constructs are currently part of the ISDC ontology and the associated OWL-file. A main part of the semantic based connections between the ISDC related classes and the class Geophenomena have been realized by the use of manually into the ISDC ontology integrated GCMD's controlled science and services keywords. In order to benefit from the hierarchical structure of GCDM's keywords, NASA's original files have been transformed into appropriate multi-language capable SKOS ontologies and afterwards integrated into the ISDC ontology. Now, existing information retrieval use cases can be extended using the SKOS vocabulary, such as e.g. broader, narrower or prefLabel. The problem of the global identification of persons and institutions within the ISDC ontology could be solved by the integration of authority data. From viaf.org provided URIs for personal and corporate names have been integrated as steady pillars into the ISDC ontology. Now persons and institutions can be unambiguously identified and further relations to publications or other information in the Web can be established. The successful educational and research activities combining geoscientists and information scientists will be extended into the areas of Open linked data and re-use of existing ontologies and controlled vocabularies.