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Unlocking the full potential of location-based services: Linked Data driven Web APIs

Raf Buyle and Ziggy Vanlishout

(Submission #90)


The Flemish Government in Belgium has an interoperability program called Open Standards for Linked Organizations (OSLO), which focuses on both technical and semantical interoperability of data and systems used for (digital) government service delivery. OSLO bridges between the geographical data and transactional e-government services. On the semantical level, information is aligned with European standards (ISA² Core Vocabularies and INSPIRE), enriched by data extensions to comply with the local context. On the technical level, we developed RESTFul APIs which build upon the principles of Linked Data (Buyle, 2017).

Because of its extensibility and since it is already a standard for data interchange on the web, Flemish Administrations have chosen the Resource Description Framework (RDF) to facilitate the creation and reuse of machine-readable data. Linked Data is often perceived as complex and verbose. JSON is a popular lightweight data-interchange format, easy for humans to read and write, but a major disadvantage is that the data is not self-describing. JSON-LD, however, is a lightweight Linked Data format. It is easy for humans to read and write and based on the already successful JSON format ( We discovered that JSON-LD was quickly embraced by the developers in designing the APIs. JSON-LD has no formal standardized method for data validation. In data-integration projects, however, there is always a need to validate if data satisfy a set of conditions. We use the Shapes Constraint Language, a W3C Recommendation for describing and validating RDF graphs, to define classes together with constraints on their properties (Knublauch & Kontokostas, 2017).

To unlock the full potential of interoperable services, we are designing hypermedia-driven Web APIs. Therefore the Flemish Government is applying a shared vocabulary, which describes common concepts such as paging and collections, paving the way towards interoperable Web APIs (Lanthaler & Gütl, 2013). This vocabulary, which is understood by both the server and the client, allows us to map the API interactions to low-level HTTP interactions (Lanthaler, 2014). The combination of JSON-LD and re-usable machine readable API contracts allows developers to create generic APIs. This approach can avoid expensive tailor-made connectors.

We have applied this strategy for raising semantic and technical interoperability using JSON-LD both for providing access to the data in our Base Registries as in the high impact project “the citizen’s profile ” that will allow 6.4 million citizens to better access and use public services.


Topic Area:  [3.6] Making INSPIRE work for ICT developers
Abstract Type:  Oral Presentation

Additional Fields

Academic:   Yes
Data Provider:   Yes
Data User:   Yes
INSPIRE Implementer (IT):   Yes
INSPIRE newbies:   Yes
Policy Officers:   Yes
Public Administration (MS/Regional/Local):   Yes
Thematic specialists:   No
Comments:   Linked Data; JSON-LD; SHACL; e-government; INSPIRE; ISA Core Vocabularies; OSLO

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