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st_convexhull function

Applies to: check marked yes Databricks Runtime 17.1 and above

Important

This feature is in Public Preview.

Returns the convex hull of the input GEOMETRY as a GEOMETRY.

Syntax

st_convexhull ( geoExpr )

Arguments

  • geoExpr: A GEOMETRY value.

Returns

Returns the convex hull of the input GEOMETRY (represented as a GEOMETRY value or using a standard geospatial format) as a GEOMETRY. More precisely:

  • If the input GEOMETRY is empty, then the GEOMETRY is returned as is.
  • If the input GEOMETRY degenerates to a point, then that point is returned.
  • If the convex hull of the input GEOMETRY degenerates to a linestring segment, which happens if all vertices in the input are collinear, that segment is returned.
  • In all other cases a polygon is returned.
  • If the input GEOMETRY is not empty and has M coordinates, the M coordinates are dropped.

Examples

> SELECT st_astext(st_convexhull(st_geomfromtext('POLYGON((0 0,20 0,20 10,15 5,5 10,0 25,0 0))')))
  POLYGON((0 0,0 25,20 10,20 0,0 0))