The Swiss geoportal has started to publish geospatial data as linked data. This geoportal is harvested by the national Swiss Open Data portal, which is in turn harvested by the European Data Portal. With this development, more context is provided to the geospatial datasets, and data can be found and re-used more easily.
Linked Data uses tuples to connect data that have a relationship with each other. The data are identified, shared and linked via their Uniform Resource Identifier (URI). The Resource Description Framework (RDF) is used to encode and link the data. Linked data can be queried via SPARQL, which is the query language for RDF.
RDF is a W3C standard enabling to formulate statements about Web resources. Resources are described via statements composed of a subject a predicate and an object, thus RDF statements are called triples. The subject and the predicate in a triple are usually URIs, while the object can be either an URI or a literal value. RDF triples are stored in a Triples Store and exposed via a so called SPARQL Endpoint.
The main benefits of this approach are:
- Data is given a context (the resources are semantically tagged)
- Data is linked
- Data is on the web (findable and reusable)
Data can be queried with SPARQL. SPARQL is the query language for RDF, the same way SQL is for relational databases.
Would you like to know more about the Linked Data service of the Swiss geoportal? Further explanations and technical details can be found here.