Voronoi Polygons

Draft: written, not yet checked by a person Operation · voronoi

One polygon per point, covering the area closer to that point than to any other.

Pitfall. The outer polygons are cut to an extent that each engine chooses differently (the points' extent, a buffer around it, or a given box).

Pitfall. Distances in a geographic CRS are measured in degrees, which distorts the polygons.

About this operation
Also called	Thiessen polygons, Create Thiessen Polygons, proximity polygons, Voronoi diagram
Group	`vector/proximity`
Checks	`crs.measure, geometry.valid`
Pitfalls	2 listed above
Columbus tool	Not stated
Notes	Not stated
Status	active
Broader	Not stated
Narrower	Not stated
Related	`buffer`

Parameters

Not stated

Direction	Name	Type	Geometry	Note
Input	`layer`	vector	point	Not stated
Output	`output`	vector	polygon	Not stated

Engine	Tool	Parameters	Differences
`geopandas`	`geopandas.GeoSeries.voronoi_polygons`	Not stated	Called on a GeoSeries of points; extend_to sets the extent to cut the outer polygons to.
`grass`	`v.voronoi`	`layer` → `input` `output` → `output`	The outer polygons are cut to the computational region.
`qgis`	`native:voronoipolygons`	`layer` → `INPUT` `output` → `OUTPUT`	BUFFER enlarges the points' extent by a percentage before cutting the outer polygons.
`sf`	`sf::st_voronoi`	`layer` → `x`	Takes one geometry: combine the points first (st_union or st_combine); envelope sets the extent.
`terra`	`terra::voronoi`	`layer` → `x`	bnd gives a boundary polygon to cut the result to.
`turf-js`	`turf.voronoi`	`layer` → `points`	options.bbox gives the extent (default the whole world: -180, -85, 180, 85). Turf works on GeoJSON in longitude/latitude (WGS 84); data in another CRS must be reprojected first.
`whiteboxtools`	`VoronoiDiagram`	`layer` → `input` `output` → `output`	None noted