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This function computes the Delaunay triangulation for the set of vertices in the input geometry. An optional tolerance parameter allows snapping nearby input vertices together prior to triangulation and can improve robustness in certain scenarios by handling near-coincident vertices. The default for tolerance is 0. The Delaunay triangulation geometry is bounded by the convex hull of the input vertex set. ST_DelaunayTriangles The output geometry representation depends on the provided flag:
  • 0 - a GeometryCollection of triangular Polygons (default option)
  • 1 - a MultiLinestring of the edges of the triangulation

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Signatures

ST_DelaunayTriangles(geometry: Geometry)

ST_DelaunayTriangles(geometry: Geometry, tolerance: Double)

ST_DelaunayTriangles(geometry: Geometry, tolerance: Double, flag: Integer)

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Parameters

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geometry
Geometry
required
The input geometry.
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tolerance
Double
The distance tolerance.
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flag
Integer
The validation flag.

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Return type

The resulting geometry.

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Example

SELECT ST_DelaunayTriangles(
        ST_GeomFromWKT('POLYGON ((10 10, 15 30, 20 25, 25 35, 30 20, 40 30, 50 10, 45 5, 35 15, 30 5, 25 15, 20 10, 15 20, 10 10))')
)

GEOMETRYCOLLECTION (POLYGON ((15 30, 10 10, 15 20, 15 30)), POLYGON ((15 30, 15 20, 20 25, 15 30)), POLYGON ((15 30, 20 25, 25 35, 15 30)), POLYGON ((25 35, 20 25, 30 20, 25 35)), POLYGON ((25 35, 30 20, 40 30, 25 35)), POLYGON ((40 30, 30 20, 35 15, 40 30)), POLYGON ((40 30, 35 15, 50 10, 40 30)), POLYGON ((50 10, 35 15, 45 5, 50 10)), POLYGON ((30 5, 45 5, 35 15, 30 5)), POLYGON ((30 5, 35 15, 25 15, 30 5)), POLYGON ((30 5, 25 15, 20 10, 30 5)), POLYGON ((30 5, 20 10, 10 10, 30 5)), POLYGON ((10 10, 20 10, 15 20, 10 10)), POLYGON ((15 20, 20 10, 25 15, 15 20)), POLYGON ((15 20, 25 15, 20 25, 15 20)), POLYGON ((20 25, 25 15, 30 20, 20 25)), POLYGON ((30 20, 25 15, 35 15, 30 20)))