In the 2.3 version, PostGIS provides a way to create Voronoi diagrams from the vertices of a geometry; this will work only with versions of GEOS greater than or equal to 3.5.0.

The following is a Voronoi diagram generated from a set of address points. Note how the points from which the diagram was generated are equidistant to the lines that divide them. Packed soap bubbles viewed from above form a similar network of shapes:

Voronoi diagrams are a space-filling approach that are useful for a variety of spatial analysis problems. We can use these to create space filling polygons around points, the edges of which are equidistant from all the surrounding points.

The PostGIS function ST_VoronoiPolygons(), receives the following parameters: a geometry from which to build the Voronoi diagram, a tolerance, which is a float that will tell the function the distance within which vertices will be treated as equivalent for the output, and an extent_to geometry that will tell the extend of the diagram if this geometry is bigger than the calculated output from the input vertices. For this recipe, we will not use tolerance, which defaults to 0.0 units, nor extend_to, which is set to NULL by default.