Reuse of library thesaurus data as ontologies for the public sector

In the spring of 2013 the National Library of Finland took on a mission to build a national level ontology infrastructure across the public sector. Central to this endeavor is the open source ontology service Finto and the General Finnish Ontology YSO. The ontology is based on the General Finnish Thesaurus, originally developed in the 1980s in the National Library mainly for book indexing. Moving from index terms used in the thesaurus to ontological concepts of YSO has made it feasible to map the ontology to other resources. Similar transformations have been employed to thesauri from other domains. By linking the various ontologized thesauri together, metadata harmonization has been achievable across databases. YSO and Finto are currently in pilot use in several organizations. Today the National Library of Finland is adopting a new role in steering the development and future practices of indexing in the world of linked data.