IB-Tool (Partitioning) — QGIS Plugin

A QGIS plugin that delineates settlement boundaries by partitioning spatial datasets based on building footprints.

This is a companion plugin to IB-Tool 3: its output (a PART_<id> polygon layer) is the Partitions input IB-Tool 3 expects — see IB-Tool 3's docs/input-data.md → Part and docs/quickstart.md for how it fits into IB-Tool 3's own workflow.

IB-Tool 3 needs four more input layers. Its sibling plugin Data Wizard produces the HU / RN / Aux layers from raw ATKIS Basis-DLM data — the building footprints it outputs can be fed straight into this plugin as input.

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What it does

The plugin generates partition polygons from building footprint data. The algorithm uses kernel density estimation on building centroids to identify settlement clusters, then derives partition boundaries via Voronoi tessellation and line processing.

Processing pipeline:

1. Building footprints → centroids
2. Kernel density raster (heatmap) from centroids
3. Raster → point grid
4. Voronoi polygons from point grid
5. Polygon to lines → explode line segments
6. Remove line segments within dense cluster areas
7. Polygonize remaining lines → partition polygons
8. Add NAME field (PART_<id>)

The result is a set of polygons that partition the study area into settlement units, each named PART_<id>.

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Requirements

• QGIS 3.0 or later
• Python 3.x (bundled with QGIS)
• No external Python packages required — all processing uses QGIS native algorithms

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Installation

From ZIP (manual)

1. Download or clone this repository
2. Open QGIS → Plugins → Manage and Install Plugins → Install from ZIP
3. Select the .zip file and click Install Plugin

From source (development)

Copy or symlink the ibtoolpartion/ directory into your QGIS plugin folder:

Platform	Plugin folder
Windows	%APPDATA%\QGIS\QGIS3\profiles\default\python\plugins\
Linux	~/.local/share/QGIS/QGIS3/profiles/default/python/plugins/
macOS	~/Library/Application Support/QGIS/QGIS3/profiles/default/python/plugins/

Then activate the plugin in QGIS via Plugins → Manage and Install Plugins.

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Usage

1. Open QGIS and activate the plugin
2. Click the IB-Tool (Partitioning) icon in the toolbar or use the Plugins menu
3. In the dialog, set:
   • Building footprints — polygon layer (.shp or .gpkg)
   • Cell size (metres) — raster resolution and density radius (default: 150)
   • Output file — destination for the partition polygon layer (.shp or .gpkg)
4. Click OK — the output layer is written to the specified file

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Parameters

Parameter	Type	Default	Description
Building footprints	Polygon layer	—	Input building footprint features
Cell size (metres)	Integer	150	Raster cell size; controls density estimation radius (2 × cell_size)
Output file	File path	—	Output partition polygon layer (.shp or .gpkg)

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Development

Setup

git clone <repo-url>
cd ibtoolpartion
python -m venv .venv
.venv\Scripts\activate   # Windows
pip install flake8 bandit detect-secrets pylint pytest pytest-cov

Run tests

# All tests (requires a running QGIS environment)
pytest test/ -v

# Unit tests only (no QGIS required)
pytest test/ -v -m unit

Run tests with Docker

docker build -t qgis-plugin-test .
docker run --rm -v $(pwd):/plugins/ibtoolpartion qgis-plugin-test

Build a release ZIP

python scripts/create_release_zip.py

Produces dist/ibtoolpartion.<version>.zip. See docs/contributing.md → Release Process for the full checklist.

Static analysis

python ci/qgis_plugin_validate.py --auto
flake8 .
bandit -r . -ll
detect-secrets scan --force-use-all-plugins

Test markers

Marker	When to use
@pytest.mark.unit	No processing.run() calls — no QGIS required
@pytest.mark.integration	Calls processing.run() — requires QGIS
@pytest.mark.edge_case	Boundary or degenerate inputs
@pytest.mark.slow	Runtime > 1 s or large datasets

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CI / CD

Workflow	Trigger	Purpose
ci.yml	Push to master/main, PRs	Docker-based tests + Codecov coverage
qgis-plugin-ci.yml	Push to master/main, PRs	Lint (flake8), security scan (bandit), plugin validation

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Citation

This plugin is based on the following published toolset:

Oliver Harig (2021). Toolset for the delineation of settlements on the basis building footprints, road network and land use data (v1.0). https://doi.org/10.26084/IOERFDZ-SOFT-001

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License

This plugin is released under the GNU General Public License v2 (or later). See LICENSE for the full license text.

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Author

Oliver Harig — ottmar.hittzfeld@web.de