Designing semantic Application Programming Interfaces for open government data

Many countries currently maintain a national data catalog, which provides access to the available datasets – sometimes via an Application Programming Interface (API). These APIs play a crucial role in realizing the benefits of open data as they are the means by which data is discovered and accessed by applications that make use of it. This article proposes semantic APIs as a way of improving access to open data. A semantic API helps to retrieve datasets according to their type (e.g., sensor, climate, finance), and facilitates reasoning about and learning from data. The article examines categories of open datasets from 40 European open data catalogs to gather some insights into types of datasets which should be considered while building semantic APIs for open government data. The results show that the probability of inter-country agreement between open data catalogs is less than 30 percent, and that few categories stand out as candidates for a transnational semantic API. They stress the need for coordination - at the local, regional, and national level - between data providers of Germany, France, Spain, and the United Kingdom.The authors gratefully acknowledge funding from the European Union through the GEO-C project (H2020-MSCA-ITN-2014, Grant Agreement Number 642332, http://www.geoc. eu/). Carlos Granell has been funded by the Ramón y Cajal Programme (grant number RYC- 2014-16913). Sergio Trilles has been funded by the postdoctoral programme Vali+d (GVA) (grant number APOSTD/2016/058)