ST_VoronoiLines
Name
ST_VoronoiLines — Returns the boundaries of the Voronoi diagram of the vertices of a geometry.
Synopsis
geometry
ST_VoronoiLines
(
geometry
geom
,
float8
tolerance = 0.0
,
geometry
extend_to = NULL
)
;
Description
Computes a two-dimensional
Voronoi diagram
from the vertices of
the supplied geometry and returns the boundaries between cells in the diagram as a MultiLineString.
Returns null if input geometry is null. Returns an empty geometry collection if the input geometry contains only one vertex.
Returns an empty geometry collection if the
extend_to
envelope has zero area.
Optional parameters:
-
tolerance: The distance within which vertices will be considered equivalent. Robustness of the algorithm can be improved by supplying a nonzero tolerance distance. (default = 0.0) -
extend_to: If present, the diagram is extended to cover the envelope of the supplied geometry, unless smaller than the default envelope (default = NULL, default envelope is the bounding box of the input expanded by about 50%).
Performed by the GEOS module.
Availability: 2.3.0
Examples
Voronoi diagram lines, with tolerance of 30 units
SELECT ST_VoronoiLines(
'MULTIPOINT (50 30, 60 30, 100 100,10 150, 110 120)'::geometry,
30) AS geom;
ST_AsText output
MULTILINESTRING((135.555555555556 270,36.8181818181818 92.2727272727273),(36.8181818181818 92.2727272727273,-110 43.3333333333333),(230 -45.7142857142858,36.8181818181818 92.2727272727273))