ST_VoronoiLines
Name
ST_VoronoiLines — Returns the boundaries of the Voronoi diagram of the vertices of a geometry.
Synopsis
geometry
ST_VoronoiLines
(
g1
geometry
,
tolerance
float8
,
extend_to
geometry
)
;
Description
ST_VoronoiLines computes a two-dimensional Voronoi diagram from the vertices of the supplied geometry and returns the boundaries between cells in that 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 a geometry is supplied as the "extend_to" parameter, the diagram will be extended to cover the envelope of the "extend_to" geometry, unless that envelope is smaller than the default envelope (default = NULL, default envelope is boundingbox of input geometry extended by about 50% in each direction).
Performed by the GEOS module.
Availability: 2.3.0
Examples
Voronoi lines with tolerance of 30 units
SELECT ST_VoronoiLines(geom, 30) As geom FROM (SELECT 'MULTIPOINT (50 30, 60 30, 100 100,10 150, 110 120)'::geometry As geom ) As g
-- 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))
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