Researchers from the Ontological Engineering Group at the Universidad Politécnica de Madrid’s Facultad de Informática are working with the Spanish National Geographical Institute - Instituto Geográfico Nacional de España (IGN) and the Spanish National Geographical Information Centre - Centro Nacional de Información Geográfica (CNIG) on linking the IGN’s data with the world linked open data network, known as Linked Open Data.

Linked Open Data (LOD) is a world data network now containing over four and a half million references organized by subject bubbles connected to each other via the Internet. This world data network is one of the pillars of the future Semantic Web.

Most of the data that Linked Open Data contains is in English, and it does not contain very many examples of geographical data as yet. For this reason, the work of the UPM’s School of Computing researchers on entering Spanish geographical data into Linked Open Data is groundbreaking.

The Spanish National Geographical Institute has accumulated a vast amount of spatial data on Spain, including geographical reference information (administrative borders, localities, hydrography, buildings, geographical names, communications networks, land occupancy, etc.). Research by the Ontological Engineering Group has started by first transforming the hydrographical information (rivers, lakes, reservoirs, etc.) in the IGN’s databases and will then move on to information on municipalities, provinces, roads, monuments and any other geospatial information of interest. The deployment of all these data in Linked Open Data will be complete by the end of 2010.

The Ontological Engineering Group at the UPM’s Facultad de Informática has linked the IGN data using technologies previously developed by this research group as part of the European NeOn Project. The technologies that they have used are known as R2O and ODEMapster.

R2O and ODEMapster make up an integrated framework for formally expressing, evaluating, verifying and using semantic correspondences between ontologies and relational databases.

The integrated framework is composed of:

• R2O, a formal declarative language that is expressive enough to represent complex correspondences by aligning two models developed and maintained separately that are likely to have all sorts of disparities.

• ODEMapster, a processor that is responsible for semantically upgrading or enriching database contents by means of the on-demand retrieval of the database contents. Data is retrieved in response to queries stated in ontology terms by means of a query re-writing process.

The Ontological Engineering Group researchers use these technologies to generate new bubbles with IGN data. These bubbles are then related to the other bubbles that are part of this world data network. A bubble is a dataset on the same subject published on the Web in conformance with LOD specifications.

By relating IGN data to LOD, they will become part of a future ecosystem of multimedia contents and interactive services connecting what are known as Web 2.0 technologies to social, semantic and geographical issues.

In this context, the IGN has commended the Ontological Engineering Group with the task of processing its data to generate bubbles in Linked Open Data. This should give all interested parties universal and more or less instant access to IGN data over the Internet.The work of the Ontology Engineering Group is contained in a specific web area called  GeolinkedData.

The UK (see video) and US Governments are also leading efforts to make their public data available to all interested parties over the Internet (data.gov, data.gov.uk), and, at the European level, there is a Commission directive aimed at making public data accessible for citizens.

The project research group is led by Asunción Gómez Pérez, Director of the UPM Facultad de Informática’s Department of Artificial Intelligence and the Ontological Engineering Group, and its members include Oscar Corcho and the geographer Luis Manuel Vilches Blázquez.

The National Geographical Institute is represented by Sebastián Mas Mayoral, Director of the National Geographical Information Centre, and Antonio Rodríguez Pascual, Head of the CNIG’s Geographical Information Infrastructure Section.