Open data is now a heavily discussed topic around the world and in the European Union. In the Czech Republic, open data is a term anchored in legislation, which includes the requirement of registration of all open data in the Czech National Open Data Portal (NODC).
In this paper we describe the NODC, its architecture, dataset registration processes including the harvesting of Local Open Data Catalogs (LODCs), proprietary XML API and its obsolete dataset viewer. Next we describe the process of transformation of the NODC metadata to the DCAT-AP v1.1 RDF representation from the data model point of view and from the technical environment point of view.
We describe the dataset quality measurements computed using the new data representation and its further impact on the Linked Open Data (LOD) environment including the harvesting of the metadata by the European Data Portal (EDP). Finally, we evaluate the data transformation and publishing environment from the usability, portability, availability and performance perspectives.