qgisparql-triple2layer

Triple2Layer

A QGIS plugin to import geographic data from SPARQL endpoints and linked data repositories into QGIS vector layers.

Part of the QGISParQL suite — see also Layer2Triple.

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Overview

Triple2Layer enables GIS users to query linked data sources — such as triple stores (Virtuoso, Apache Jena Fuseki) or Data.world — using SPARQL and load the results directly as geographic layers in QGIS.

The plugin bridges the Semantic Web and GIS workflows, allowing data encoded in RDF/WKT format to be visualized and analyzed in a familiar GIS environment.

Features

• Query any SPARQL 1.1-compliant triple store endpoint.
• Import data from Data.world datasets (requires API token).
• Asynchronous Task Management: Imports run in the background without freezing the QGIS interface.
• Auto-Geometry Detection: Automatically identifies point, line, or polygon layers from WKT strings.
• Dynamic Attribute Mapping: Configure names and types (String, Int, Double) before import.

Installation

1. Plugin Installation

Download or clone this repository and copy the folder to your QGIS plugins directory:

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

Note: Restart QGIS and enable the plugin under Plugins → Manage and Install Plugins.

2. Python Dependencies (Crucial)

Because QGIS uses its own Python environment, dependencies must be installed correctly to avoid version conflicts (especially with pandas in Python 3.12+).

On Linux (Ubuntu/Debian/Fedora)

Open your terminal and run the commands in this exact order:

# 1. Install core build tools and pandas first
pip install pandas setuptools --break-system-packages

# 2. Install data.world and SPARQLWrapper
pip install datadotworld SPARQLWrapper --break-system-packages

On Windows

1. Search for OSGeo4W Shell in your Start Menu and run it as Administrator.
2. Run the following command:

pip install pandas setuptools datadotworld SPARQLWrapper

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🔑 Authentication (data.world)

If you plan to use Data.world, you need an API Token. Triple2Layer provides three ways to handle this:

1. In-Plugin: Go to the plugin’s Settings menu and enter your token. It will be saved securely in QGIS persistent settings.
2. Environment Variable: Set DW_AUTH_TOKEN in your system.
3. CLI Config: If you have run dw configure in your terminal, the plugin will automatically detect the token in ~/.dw/config.

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Usage

1. Go to Vector → QGISParQL → Triple2Layer.
2. Layer Name: Enter a name for the output layer.
3. Source: Select Triple Store or Data.world.
4. Endpoint: Enter the URL or Dataset path (e.g., user/dataset-name).
5. SPARQL: Load a .sparql file. The plugin will parse the variables automatically.
6. Attributes: Map your SPARQL variables to QGIS fields and select the Geometry Column (must be WKT).
7. Import: Click to start the background task. Follow progress in the status bar.

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Authors

• Sérgio Souza Costa — @profsergiocosta — sergio.costa@ufma.br
• Nerval Junior — @nervaljunior

LambdaGeo Research Group — Universidade Federal do Maranhão (UFMA).

Citation

If you use this plugin in your research, please cite it as:

@software{costa2026triple2layer,
  author  = {Costa, Sérgio Souza and Junior, Nerval},
  title   = {Triple2Layer: A QGIS Plugin for Importing Linked Geographic Data},
  year    = {2026},
  publisher = {GitHub},
  journal = {GitHub repository},
  url     = {https://github.com/LambdaGeo/qgisparql-triple2layer}
}

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