Florian Hahn
Researcher in Semantic Open Data, Web Technologies & Public Data Infrastructures
🔍 Motivation & Vision
SODIC is a research group at Chemnitz University of Technology focused on advancing open and semantic data infrastructures. We explore how structured, interoperable and spatially linked data can foster innovation, transparency and collaboration across public administration, science and civil society.
In a world increasingly driven by data, the accessibility, semantics and interoperability of Open Data are more important than ever. SODIC stands at the intersection of technology, governance and transparency, pushing for intelligent Open Data infrastructures that empower society, science and administration.
👨🔬 Team
Prof. Dr. Michael Martin
Professor of Data Management and expert in Linked Data, semantics and data architectures
🧪 Current Research
SODPUB - Semantic Open Data Publisher
Standardized Open Data Publication & Utilization Blueprint
SODPUB is a Docker-based tool for enhancing pre-publication processes for Open Data. It supports CSV input files and produces an enhanced CSV file, an improved metadata file and a reproducible publication file, prepared for semantic interoperability in RDF format.
This work is the main focus at the moment. There is no official release yet, but the architecture-level repository is available.
SODS
SODS is a survey based on DACH region Open Data portals. It gathers information about the current state of Open Data portals, including best practices, standards, interoperability and current work. The survey took place in January 2026.
SODREPO - Spatial Open Data Regions and Portals
An interactive map-based tool linking Open Data portals to administrative boundaries across Europe.
SODORG - Semantic Open Data Organisation as an Ontology Approach
SODORG contains a small, reproducible example knowledge graph demonstrating how to model time-scoped organizational structures and thematic assignments for German public-sector actors in the context of Open Government Data.
SODCET - Semantic Open Data Category Extraction Tools
This Python-based research tool executes and aggregates data extraction scripts for all 16 German federal states. Each script targets specific Open Data sources, including state portals and ArcGIS endpoints, and parses region-specific datasets.
The result is a unified metadata corpus that can be used for semantic analysis, statistical evaluation or integration into RDF graphs.
SODINA - SPARQL for Open Data Introspection, Navigation and Access
SODINA is a lightweight introspection layer for SPARQL endpoints, designed to support semantic data exploration by dynamically exposing available classes, properties, datatypes and value samples. Inspired by GraphQL's __schema functionality, SODINA lowers the entry barrier for users unfamiliar with the internal vocabulary of RDF-based Open Data portals.
SODMET - Semantic Open Data Metadata Extraction Tools
This Node.js-based research tool analyzes the metadata quality of German municipal Open Data portals. It evaluates the regional assignability of datasets depending on whether standardized metadata models such as DCAT-AP and GeoDCAT-AP are used, for example via CKAN, best practice as a SPARQL endpoint or non-standard formats such as ArcGIS JSON.
Former name: SODRAM, Specific Open Dataset Regional Analysis Metadata.
SODBond - Semantic-Orchestration Derivation Bond between BPMN and RDF
SODBond is a toolkit that bridges Camunda BPMN 2.0 process definitions and runtime instances with RDF knowledge graphs via an ontology-driven approach. It retrieves BPMN models and instance data from Camunda through the REST API and transforms them into semantically rich RDF/OWL representations based on a BPMN-based ontology.
SODPEST - SPARQL Open Data Portal Endpoint SPARQL Tester
SODPEST is a small, dependency-light CLI tool that derives SPARQL endpoint candidates for Open Data portals and optionally verifies them via real SPARQL protocol checks.
SODDUT - Semantic Open Data Dataset Update Timeline
SODDUT is an interactive timeline to check the corresponding creation and updating process of an Open Data dataset.
✅ Planned Projects
SODA
Saxony Open Data Assembly
Planned
🧾 Publications
2026
- Hahn, F. (2026). SODPUB: A BPMN-Orchestrated Workflow-as-a-Service for Interoperability-Oriented Pre-publication Quality Improvement in Open Government Data. ICWE 2026.
- Hahn, F. (2026). Measuring Semantic Comparability in Federal Open Data: Evidence from German State Portals. DGO 2026.
- Hahn, F. (2026). SODS: Surveying Interoperability Readiness in DACH Open Data Portals. DGO 2026.
- Hahn, F. (2026). From Federal Heterogeneity to Reproducible Analytics: A Provenance-Aware Knowledge Graph for Cross-Portal Comparability of German Open Government Data. KGCW 2026 at ESWC 2026.
2025
- Hahn, F. (2025). Ontology Driven Transformation of Camunda BPMN Instances into RDF Knowledge Graphs. NFDI4DS 2025.
- Hahn, F. (2025). Geographical Provenance of Open Government Datasets: Evaluating Geospatial Metadata in Municipal Open Data Portals. DCMI 2025.
- Hahn, F. (2025). Bridging gaps in the Open Data landscape: A step towards a global atlas. ICEGOV 2025.
- Hahn, F. (2025). Towards an Standardized Dataset Publishing in Open Government Data Ecosystems. ESWC 2025.