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https://github.com/longavailable/voronoi-diagram-for-polygons

A tool to create a Voronoi diagram for polygons
https://github.com/longavailable/voronoi-diagram-for-polygons

geospatial-processing thiessen-polygons voronoi-diagram voronoi-polygons

Last synced: 5 days ago
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A tool to create a Voronoi diagram for polygons

Host: GitHub
URL: https://github.com/longavailable/voronoi-diagram-for-polygons
Owner: longavailable
License: mit
Created: 2020-07-25T21:50:00.000Z (over 4 years ago)
Default Branch: main
Last Pushed: 2024-12-10T03:44:21.000Z (about 1 month ago)
Last Synced: 2024-12-30T16:47:47.416Z (12 days ago)
Topics: geospatial-processing, thiessen-polygons, voronoi-diagram, voronoi-polygons
Language: Python
Homepage: https://longlovemyu.com/voronoi-diagram-for-polygons/
Size: 740 KB
Stars: 46
Watchers: 2
Forks: 11
Open Issues: 0
Metadata Files:
- Readme: README.md
- License: LICENSE
- Citation: CITATION.cff

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README

                                     

# Voronoi diagram for polygons

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[![Downloads](https://pepy.tech/badge/voronoi-diagram-for-polygons)](https://pepy.tech/project/voronoi-diagram-for-polygons)

[![DOI](https://zenodo.org/badge/DOI/10.5281/zenodo.3960407.svg)](https://doi.org/10.5281/zenodo.3960407)

[Voronoi diagram for polygons] is a tool to create a [Voronoi diagram] also known as [Thiessen polygons] for **polygons**. It's based on [Shapely] and [GeoPandas]. There are lots of tools to create a [Voronoi diagram] for points, for example [Create Thiessen Polygons (Analysis)] in [ArcGIS Pro] or [ArcGIS Desktop], [Voronoi Polygons] in [QGIS], or [voronoi_diagram] in [Shapely]. All of them are really cool. How about a [Voronoi diagram] for polygons? That's what this tool does.









[***Important!***](#dependencies) You have to install or upgrade to the latest developing version of [Shapely] before install [Voronoi diagram for polygons]

## Table of contents

- [Installation, update and uninstallation](#installation--update-and-uninstallation)

	* [Dependencies](#dependencies)

  * [To install](#to-install)

  * [To update](#to-update)

  * [To uninstall](#to-uninstall)

- [Usage](#usage)

- [FAQ](#faq)

- [Known shortages](#known-shortages)

- [How to cite?](#how-to-cite)

- [Changelog](#changelog)

## Installation, update and uninstallation

### Dependencies

***Important!*** It's based on `voronoi_diagram` from [Shapely] which is new in version 1.8.dev0. As of today, it is still a developing version. *(2020-07-26)* You have to install or upgrade to the latest developing version from source firstly:

```bash

pip install git+https://github.com/Toblerity/Shapely

```

```bash

pip install --upgrade git+https://github.com/Toblerity/Shapely

```

### To install

Quick installation with `pip`:

```bash

pip install voronoi-diagram-for-polygons

```

Or from github:

```bash

pip install git+https://github.com/longavailable/voronoi-diagram-for-polygons

```

Also, you can just copy related functions from *[longsgis/longsgis.py]* to your work.

### To update

```bash

pip install --upgrade voronoi-diagram-for-polygons

```

### To uninstall

```bash

pip uninstall voronoi-diagram-for-polygons

```

## Usage

See *[tests/01voronoiDiagram4plg.py]*.

```python

import geopandas as gpd

from longsgis import voronoiDiagram4plg

builtup = gpd.read_file('input.geojson'); builtup.crs = 32650

boundary = gpd.read_file('boundary.geojson'); boundary.crs = 32650

vd = voronoiDiagram4plg(builtup, boundary)

vd.to_file('output.geojson', driver='GeoJSON')

```

## FAQ

- I/O support.

	It was noticed someone were struggled with the input/output files with a format of `.geojson` (https://github.com/longavailable/voronoi-diagram-for-polygons/issues/3, https://github.com/longavailable/voronoi-diagram-for-polygons/issues/5). Actually, that's not a question related to this package. I will explain more here about it. This package is totally based on [GeoPandas]. In other words, any format that can be converted to `geopandas.GeoDataFrame` object is supported. As the [official documentation](https://geopandas.org/en/stable/docs/user_guide/io.html#reading-spatial-data) said:

	> geopandas can read almost any vector-based spatial data format including ESRI shapefile, GeoJSON files and more using the command: `geopandas.read_file()`

	

	That means, you can put your `.shp` files as inputs and output as well. Any format you'd like. I used a few geojson-s (`input.geojson`, `boundary.geojson`, and `output.geojson`) in my example because the geojson format is very open. However, it's NOT necessary.

	

	For more, I upload the [input.geojson] and [boundary.geojson] files. Hope they helps. For the sake of caution, I declare here that they are only a test file, any actual geographical data, similar or not, I have no guarantee to the accuracy and authenticity for them.

## Known shortages

- It may produce multipolygons (consisted by some unconnected polygons) around the boundary.

	

- Special input may cause overlap. See the following:

	


	

	

	

	

	*To avoid this, I recommend reasonable preprocessing of the input, but use a buffer operation with high-resolution carefully.* A buffer operation with high-resolution will result in circular arcs, which will generate too many vertices in a local area. This may trigger other bugs. In my practices, the following code snippet worked well.

	

```python

def bufferDissolve(gdf, distance, join_style=3):	

	'''Create buffer and dissolve thoese intersects.

	

	Parameters:

		gdf: 

			Type: geopandas.GeoDataFrame

		distance: radius of the buffer

			Type: float

	Returns:

		gdf_bf: buffered and dissolved GeoDataFrame

			Type: geopandas.GeoDataFrame

	'''

	#create buffer and dissolve by invoking `unary_union`

	smp = gdf.buffer(distance, join_style).unary_union

	#convert to GeoSeries and explode to single polygons

	gs = gpd.GeoSeries([smp]).explode()

	#convert to GeoDataFrame

	gdf_bf = gpd.GeoDataFrame(geometry=gs, crs=gdf.crs).reset_index(drop=True)

	return gdf_bf

```

## How to cite

If this tool is useful to your research, 

star and cite it as below:

```

Xiaolong Liu, & Meixiu Yu. (2020, July 26). longavailable/voronoi-diagram-for-polygons. Zenodo. 

http://doi.org/10.5281/zenodo.3960407

```

Easily, you can import it to 

 Mendeley.

## Changelog

### v0.1.1

- First release.

### v0.1.2

- Fix a [FutureWarning](https://pandas.pydata.org/docs/whatsnew/v1.4.0.html#whatsnew-140-deprecations-frame-series-append).

### v0.1.3

- Make it more robust for the less-vertice-geometry inputs. [#4](https://github.com/longavailable/voronoi-diagram-for-polygons/issues/4#issue-1378217062).

- Fix a few ***FutureWarnings***.

### v0.1.6 (Merged)

- Change as [Shapely] goes. `MultiPolygon` is not iterable any more from [Shapely] 2.0.

- Upload a few test data.

[Voronoi diagram for polygons]: https://github.com/longavailable/voronoi-diagram-for-polygons

[Voronoi diagram]: https://en.wikipedia.org/wiki/Voronoi_diagram

[Thiessen polygons]: https://en.wikipedia.org/wiki/Voronoi_diagram

[Shapely]: https://shapely.readthedocs.io/en/latest/

[GeoPandas]: https://geopandas.org/index.html

[Create Thiessen Polygons (Analysis)]: https://pro.arcgis.com/en/pro-app/tool-reference/analysis/create-thiessen-polygons.htm

[ArcGIS Pro]: https://www.esri.com/en-us/arcgis/products/arcgis-pro/overview

[ArcGIS Desktop]: https://desktop.arcgis.com/en/

[Voronoi polygons]: https://docs.qgis.org/3.10/en/docs/user_manual/processing_algs/qgis/vectorgeometry.html#voronoi-polygons

[QGIS]: https://qgis.org/en/site/

[voronoi_diagram]: https://shapely.readthedocs.io/en/latest/manual.html?#voronoi-diagram

[longsgis/longsgis.py]: https://github.com/longavailable/voronoi-diagram-for-polygons/raw/main/longsgis/longsgis.py

[tests/01voronoiDiagram4plg.py]: https://github.com/longavailable/voronoi-diagram-for-polygons/raw/main/tests/01voronoiDiagram4plg.py

[input.geojson]: https://github.com/longavailable/voronoi-diagram-for-polygons/raw/main/tests/input.geojson

[boundary.geojson]: https://github.com/longavailable/voronoi-diagram-for-polygons/raw/main/tests/boundary.geojson

### v0.1.7

- Enhance the applicability to geometry coordinate system (GCS). [#10](https://github.com/longavailable/voronoi-diagram-for-polygons/issues/10#issue-2696433193).

- Refactor `dropHoles()` by [jwardbond](https://github.com/jwardbond).

### v0.1.8

By [jwardbond](https://github.com/jwardbond)，

- Update `densify_polygons()` to keep the original columns.

- Automate code formatting with [ruff](https://docs.astral.sh/ruff/) and configure it using `pyproject.toml`.