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PolarDB:ST_HasArc

Last Updated:Mar 28, 2026

Tests if a geometry or GeometryCollection contains a ring. Returns true if a ring is found, false otherwise.

Syntax

boolean ST_HasArc(geometry geomA);

Parameters

ParameterDescription
geomAThe geometry or GeometryCollection to test.

Usage notes

  • Supports 3D geometries and preserves z coordinates.

  • Supports circular strings and curves.

Examples

The following example tests a GeometryCollection that contains a POINT and a CIRCULARSTRING. Because the collection includes a ring, the function returns t.

SELECT ST_HasArc('GeometryCollection(POINT(1 0),CIRCULARSTRING(1 2,3 4,5 6))'::geometry);
 st_hasarc
-----------
 t
(1 row)

What's next

  • ST_CurveToLine: Converts a geometry that contains circular arcs to a linear approximation.

  • ST_LineToCurve: Converts a linear geometry to its curved representation.