A Connector for Integrating NGSI-LD Data into Open Data Portals

TL;DR

The paper tackles the challenge of aligning NGSI-LD-based IoT data with Open Data portals that rely on DCAT-AP metadata. It introduces a three-phase connector that (i) creates NGSI-LD descriptions from dataset metadata, (ii) publishes these descriptions into a CKAN Open Data instance, and (iii) serialises the metadata into DCAT-AP-compliant graphs for portal consumption. Key contributions include a detailed data-model mapping between DCAT-AP/CKAN and NGSI-LD Smart Data Models, the NGSI-LD→CKAN harvesting workflow with a Retriever proxy, and a DCAT-AP EDp-mqa extension for full serialization. Real-world validation demonstrates strong FAIR-principles performance on datasets exposed via the European Data Portal, confirming improved findability, accessibility, interoperability, and reusability of open data described through NGSI-LD. The work provides a practical, extensible blueprint for integrating heterogeneous open data ecosystems and IoT context data at scale.

Abstract

Nowadays, there are plenty of data sources generating massive amounts of information that, combined with novel data analytics frameworks, are meant to support optimisation in many application domains. Nonetheless, there are still shortcomings in terms of data discoverability, accessibility and interoperability. Open Data portals have emerged as a shift towards openness and discoverability. However, they do not impose any condition to the data itself, just stipulate how datasets have to be described. Alternatively, the NGSI-LD standard pursues harmonisation in terms of data modelling and accessibility. This paper presents a solution that bridges these two domains (i.e., Open Data portals and NGSI-LD-based data) in order to keep benefiting from the structured description of datasets offered by Open Data portals, while ensuring the interoperability provided by the NGSI-LD standard. Our solution aggregates the data into coherent datasets and generate high-quality descriptions, ensuring comprehensiveness, interoperability and accessibility. The proposed solution has been validated through a real-world implementation that exposes IoT data in NGSI-LD format through the European Data Portal (EDP). Moreover, the results from the Metadata Quality Assessment that the EDP implements, show that the datasets' descriptions generated achieve excellent ranking in terms of the Findability, Accessibility, Interoperability and Reusability (FAIR) data principles.

Figures (7)

• Figure S1: High-level solution setup.
• Figure S2: Component architecture of the initial stage.
• Figure S3: Component architecture of the second stage.
• Figure S4: Component architecture of the additional step towards full interoperability.
• Figure S5: Architecture of the use case with the set of connectors.