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16.5.2.7 GeometryCollection Functions »
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16.5.2.6. MultiPolygon Functions

  • Area(mpoly)

    Returns as a double-precision number the area of the MultiPolygon value mpoly, as measured in its spatial reference system. 

    mysql> SET @mpoly =
    -> 'MultiPolygon(((0 0,0 3,3 3,3 0,0 0),(1 1,1 2,2 2,2 1,1 1)))';
mysql> SELECT Area(GeomFromText(@mpoly));
+----------------------------+
| Area(GeomFromText(@mpoly)) |
+----------------------------+
|                          8 |
+----------------------------+

The OpenGIS specification also defines the following functions, which MySQL does not implement:

  • Centroid(mpoly)

    Returns the mathematical centroid for the MultiPolygon value mpoly as a Point. The result is not guaranteed to be on the MultiPolygon.

  • PointOnSurface(mpoly)

    Returns a Point value that is guaranteed to be on the MultiPolygon value mpoly.