On the Semantic Analysis of Open (Government) Data Portals’ Metadata Provision and Schema

The ever-increasing amount of data available through Open Data portals follows the momentum and proliferation of Open Data initiatives and, apart from the numerous benefits offered, poses a reality which brings forth several challenges. Metadata quality and management are key aspects in this regard; in their absence affecting the interoperability, findability, and consequently, open data consumption. The present study aims to analyse several semantic aspects of 3 major international data portals and their metadata schemas mapped to the main DCAT schema classes in order to assess the current status regarding metadata provision and aiming towards prospective standardisation and improved semantic interoperability of the datasets available. The analysis revealed several persisting challenges, including the lack of standardised information (e.g., controlled vocabularies) as accepted values of the identified mandatory metadata fields in use, or, in the case of existing standardisation schemas, a misalignment and lack of consensus among the different portals. The study also pinpoints future research lines centred around the elicitation of guidelines and practices to standardise not only descriptive but also domain-specific metadata provision across the portals, facilitating the process towards the identification of minimum sets of metadata descriptions applicable to various contexts, and reaching one step closer to the envisioned interoperable ODPs paradigm.