A file will not load
Check the serialisation is one of RDF/XML, Turtle, JSON-LD or N-Triples, and that the file is well-formed. A single syntax error will stop the whole file parsing.
Web application
RDF Graph Viewer
Explore RDF knowledge graphs in the browser: upload Turtle, RDF/XML, JSON-LD or N-Triples, inspect metadata and namespaces, browse an interactive graph, and query it with SPARQL.
Overview
A browser application for visualising and exploring RDF graphs. You upload an RDF file, it extracts metadata and namespaces, you choose which properties to draw, and it renders an interactive network you can search, rearrange and query with SPARQL.
It runs entirely in the browser. There is nothing to install and no Python environment to maintain.
Two editions: this is the web edition, a newer generation built on the desktop edition. Both are available: use this one to work without installing anything, the desktop one to keep files on your own machine.
Built for ontoterminologies
Like the desktop edition, the viewer handles ontoterminologies built in Tedi. Those graphs are hard for general-purpose RDF viewers: they combine the RDF, RDFS, SKOS, OWL, OntoLex-Lemon and OTV vocabularies, and they use punning, treating classes as instances. That combination is what motivated writing the program rather than using an existing tool.
Requirements
| Browser | Any current Chrome, Firefox, Edge or Safari |
|---|---|
| Installation | None |
| Operating system | Any |
| Address | rdf.humanisticadigitalia.eu |
Supported formats
| RDF/XML | .rdf, .xml |
|---|---|
| Turtle | .ttl |
| JSON-LD | .jsonld |
| N-Triples | .nt |
N-Triples is the addition over the desktop edition, which takes the other three. Files exported from Tedi and from the Knowledge Graph Editor are RDF/XML, so both load directly.
Workflow
- Upload a file: choose an RDF file in any of the four supported serialisations.
- Inspect the metadata: graph statistics, declared namespaces and any ontology-level metadata.
- Select properties: choose which relations you want drawn before generating the graph.
- Explore the graph: drag, search and rearrange the network.
- Query with SPARQL: run queries against the file you have loaded.
Choose properties first: drawing every property at once is slow on a large graph. Selecting a handful before generating is almost always the right move.
The SPARQL panel queries your own uploaded file. To query the lab's published datasets, use the TALOS SPARQL Query Endpoint instead.
Selecting properties
Properties are sorted automatically into three kinds:
- Object properties: the object is a URI reference; these are the relations between resources.
- Data properties: the object is a literal: a string, a number, a date.
- Annotation properties: labels and comments, used for human-readable descriptions.
A worked example: displaying an ontoterminology of kraters, selecting
otv:isA alone gives the concept hierarchy; adding
otv:denotedByTerm brings in the terms denoting each concept. Two
properties, two very different readings of the same file.
Troubleshooting
The graph renders slowly or hangs
Too many properties selected, or too large a file. Select fewer properties before generating.
A namespace is missing
Only namespaces declared in the file header are listed, not ones inferred from use. Add the declaration to the source file.
No ontology metadata shown
Dublin Core is read from owl:Ontology declarations. A file without
one will show statistics but no metadata.
Licence & credits
Developed by Dr Maria Papadopoulou, Research Group Leader at the TALOS AI4SSH Laboratory, University of Crete, within the Horizon Europe project grant agreement 101087269. It builds on the desktop edition by Prof. Christophe Roche.
Licence
Released under the PolyForm Noncommercial 1.0.0. You may use, modify and share it for any purpose that is not primarily intended for commercial advantage or monetary compensation: research, teaching and personal use all qualify. Copies and modified versions must carry the licence and the notices that came with them. The software is provided as is, without warranty.
PolyForm Noncommercial is a source-available licence rather than an open source one: the noncommercial restriction is not permitted under the Open Source Definition.
Citation
Papadopoulou, M. (2026). RDF Graph Viewer, web edition.
TALOS AI4SSH Laboratory, University of Crete.
https://rdf.humanisticadigitalia.eu/