描述

返回包含几何图形的最小圆形多边形。

	该圆由一个多边形近似，默认为每个四分之一圆48个线段。由于该多边形是最小边界圆的近似值，因此输入几何体中的某些点可能不包含在该多边形内。可以通过增加分段数来提高近似值，而几乎不会对性能造成影响。对于不适合使用多边形近似的应用程序，可以使用ST_MinimumBordingRadius。

它通常与多个和几何体集合一起使用。尽管它不是聚集体，但您可以将其与ST_Collect结合使用，以获得一组几何图形的最小边界圆。ST_MinimumBoundingCircle(ST_Collect(somepointfield)).

多边形面积除以其最小边界圆面积的比率通常称为Roeck检验。

由GEOS模块执行。

可用性：1.4.0

另请参阅

ST_Collect, ST_MinimumBoundingRadius

示例

SELECT d.disease_type,
    ST_MinimumBoundingCircle(ST_Collect(d.geom)) As geom
    FROM disease_obs As d
    GROUP BY d.disease_type;

点和线串的最小边界圆。用8段曲线逼近四分之一圆

SELECT ST_AsText(ST_MinimumBoundingCircle(
        ST_Collect(
            ST_GeomFromText('LINESTRING(55 75,125 150)'),
                ST_Point(20, 80)), 8
                )) As wktmbc;
wktmbc
-----------
POLYGON((135.59714732062 115,134.384753327498 102.690357210921,130.79416296937 90.8537670908995,124.963360620072 79.9451031602111,117.116420743937 70.3835792560632,107.554896839789 62.5366393799277,96.6462329091006 56.70583703063,84.8096427890789 53.115246672502,72.5000000000001 51.9028526793802,60.1903572109213 53.1152466725019,48.3537670908996 56.7058370306299,37.4451031602112 62.5366393799276,27.8835792560632 70.383579256063,20.0366393799278 79.9451031602109,14.20583703063 90.8537670908993,10.615246672502 102.690357210921,9.40285267938019 115,10.6152466725019 127.309642789079,14.2058370306299 139.1462329091,20.0366393799275 150.054896839789,27.883579256063 159.616420743937,
37.4451031602108 167.463360620072,48.3537670908992 173.29416296937,60.190357210921 176.884753327498,
72.4999999999998 178.09714732062,84.8096427890786 176.884753327498,96.6462329091003 173.29416296937,107.554896839789 167.463360620072,
117.116420743937 159.616420743937,124.963360620072 150.054896839789,130.79416296937 139.146232909101,134.384753327498 127.309642789079,135.59714732062 115))
                

另请参阅

ST_Collect, ST_MinimumBoundingRadius