QGISSPARQL

QGISSPARQL is a QGIS plugin that enables bidirectional integration between Linked Data (RDF/SPARQL) and Geographic Information Systems (GIS).

It allows users to both:

• 🔽 Import RDF data from SPARQL endpoints into QGIS layers.
• 🔼 Export GIS layers into RDF triples (GeoSPARQL-compatible).

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🚀 Overview

QGISSPARQL bridges the gap between the Semantic Web and GIS workflows, providing a unified environment to:

• Query SPARQL endpoints (e.g., Virtuoso, Apache Jena Fuseki).
• Load results directly as vector layers in QGIS.
• Convert geospatial layers into RDF triples.
• Publish or reuse data in Linked Data ecosystems.

Unlike traditional workflows that require scripts or intermediate formats, QGISSPARQL enables end-to-end RDF ↔ GIS integration directly inside QGIS.

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✨ Features

🔽 Triple → Layer (Import)

• Query any SPARQL 1.1 endpoint.
• Integration with data.world datasets.
• Background execution (non-blocking tasks).
• Automatic geometry detection from WKT.
• Dynamic attribute mapping.

🔼 Layer → Triple (Export)

• Convert vector layers (point, line, polygon) to RDF.
• Turtle serialization support.
• URI generation strategies (UUID or attribute-based).
• Mapping of attributes to RDF vocabularies (GeoSPARQL, SKOS, Data Cube).
• Searchable URI selection with autocompletion.

🧠 Advanced Features

• Unified dock interface with tabs (Import / Export).
• Vocabulary loading (GeoSPARQL, DataCube, SKOS, FOAF).
• Persistent configuration (e.g., data.world API tokens).
• Intelligent mapping UI with preview of auto-generated URIs.

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🖥️ Interface

The plugin provides a unified dock with two main tabs:

🔽 Triple → Layer (Import)

Execute SPARQL queries and load results into QGIS.

🔼 Layer → Triple (Export)

Convert GIS layers into RDF triples.

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📦 Installation

1. Install Plugin

Clone or download this repository:

git clone https://github.com/LambdaGeo/qgissparql

Copy to your QGIS plugins directory:

• Linux: ~/.local/share/QGIS/QGIS3/profiles/default/python/plugins/
• Windows: %APPDATA%\QGIS\QGIS3\profiles\default\python\plugins\

Restart QGIS and enable the plugin via:

Plugins → Manage and Install Plugins

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2. Install Python Dependencies

Linux

pip install pandas setuptools --break-system-packages
pip install datadotworld SPARQLWrapper rdflib --break-system-packages

Windows (OSGeo4W Shell)

pip install pandas setuptools datadotworld SPARQLWrapper rdflib

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🔑 Authentication (data.world)

You can configure your API token in three ways:

1. Inside QGIS plugin settings (Save Token button in the dock).

2. Environment variable:

   DW_AUTH_TOKEN=your_token
   

3. CLI configuration:

   dw configure
   

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▶️ Usage

Import (Triple → Layer)

1. Open: Vector → QGISSPARQL → Open Dock.
2. Select Source type (SPARQL endpoint or data.world).
3. Write or load a SPARQL query (formatting and indentation are preserved).
4. Define geometry column (WKT).
5. Execute import.

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Export (Layer → Triple)

1. Select a vector layer.
2. Define Base namespace and ID attribute.
3. Map attributes to RDF properties (searchable).
4. Optionally load a vocabulary (GeoSPARQL, etc.).
5. Export to .ttl.

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👥 Authors

• Sérgio Souza Costa — https://github.com/profsergiocosta
• Nerval de Jesus Santos Junior — https://github.com/nervaljunior
• Felipe Martins Sousa
• José Magno Pinheiro Alves
• Denilson da Silva Bezerra

LambdaGeo Research Group Universidade Federal do Maranhão (UFMA)

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📖 Citation

If you use this software, please cite:

@article{costa2026qgissparql,
  author  = {Costa, Sergio Souza and Santos Junior, Nerval and Sousa, Felipe Martins and Alves, Jose Magno Pinheiro and Bezerra, Denilson da Silva},
  title   = {QGISSPARQL: Bidirectional Integration between Linked Data and Geographic Information Systems},
  journal = {Journal of Open Source Software},
  year    = {2026},
  note    = {Under review}
}

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🤝 Contributing

Contributions, issues, and feature requests are welcome! Please check CONTRIBUTING.MD.

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📜 License

MIT License