[GIS] Splitting polygon into equal area polygons using QGIS

equal areapolygonqgis-3splitting

There is a Plugin in QGIS 2.18 called "Polygon Divider" which divides an irregular polygon into smaller equal-area polygons of a specified/custom-sized but in QGIS 3.x version there is no "Polygon Divider" Plugin or tool to perform that task.

How do I divide/split the irregular polygon into equal area/parts polygons in QGIS 3.6?

As shown in the below picture:

example

Best Answer

All of the necessary tools can be found from processing toolbox and you have to be a bit innovative to achieve this. Basically by adopting this method you could achieve pretty good results, although it doesn't give you 90 degree angles in all places, but roughly equal area:

1.Create enough random points inside a polygon. I did 10 000 10 000 random points inside a polygon

  1. Run k-means clustering for the random points. Use as many clusters as many areas you want:

Clustered points colored based on cluster_id

  1. Run Vector Geometry --> Aggregate and use the cluster id as the aggregation field. This way you will get a multipoint layer from the clusters.

  2. Run Vector geometry --> centroids for the aggregated points Centroids for each new area

  3. Run Voronoi polygons for the centroids. Use enough buffer to cover the whole original polygon. For me this was around 40% Split layer

  4. Create lines from the voronoi polygons (Vector geometry --> polygons to lines). Currently I think you can only split a polygon layer with lines and not with another polygon layer (not 100% sure about this, but this works for sure). Line layer used for splitting

  5. Finally run Split with Lines tool and use your original polygon layer as input and voronoi lines as the split layer:

Final result!

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