Name
ST_MaximumInscribedCircle — Computes the largest circle contained within a geometry.
Synopsis
(geometry, geometry, double precision) ST_MaximumInscribedCircle(geometry geom);
Description
Finds the largest circle that is contained within a (multi)polygon, or which does not overlap any lines and points. Returns a record with fields:
center- center point of the circlenearest- a point on the geometry nearest to the centerradius- radius of the circle
For polygonal inputs, the circle is inscribed within the boundary rings, using the internal rings as boundaries. For linear and point inputs, the circle is inscribed within the convex hull of the input, using the input lines and points as further boundaries.
Availability: 3.1.0.
Requires GEOS >= 3.9.0.
Examples
Maximum inscribed circle of a polygon. Center, nearest point, and radius are returned.
SELECT radius, ST_AsText(center) AS center, ST_AsText(nearest) AS nearest
FROM ST_MaximumInscribedCircle(
'POLYGON ((40 180, 110 160, 180 180, 180 120, 140 90, 160 40, 80 10, 70 40, 20 50, 40 180),
(60 140, 50 90, 90 140, 60 140))');
radius | center | nearest
-----------------+----------------------------+---------------
45.165845650018 | POINT(96.953125 76.328125) | POINT(140 90)
Maximum inscribed circle of a multi-linestring. Center, nearest point, and radius are returned.