> For the complete documentation index, see [llms.txt](https://mariadb.com/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mariadb.com/docs/server/reference/sql-statements/geometry-constructors/polygon-properties.md).

# Polygon Properties

{% columns %}
{% column %}
{% content-ref url="/pages/MyH9uYaOgSagCWnFiMGB" %}
[CENTROID](/docs/server/reference/sql-statements/geometry-constructors/polygon-properties/centroid.md)
{% endcontent-ref %}
{% endcolumn %}

{% column %}
Synonym for ST\_CENTROID. Returns the mathematical centroid of the Polygon or MultiPolygon as a Point geometry.
{% endcolumn %}
{% endcolumns %}

{% columns %}
{% column %}
{% content-ref url="/pages/lVPIBe2CFpEnmdisdzrf" %}
[AREA](/docs/server/reference/sql-statements/geometry-constructors/polygon-properties/polygon-properties-area.md)
{% endcontent-ref %}
{% endcolumn %}

{% column %}
Synonym for ST\_AREA. Returns the double-precision area of the Polygon or MultiPolygon, calculated in its spatial reference system.
{% endcolumn %}
{% endcolumns %}

{% columns %}
{% column %}
{% content-ref url="/pages/HdujdEnkqmAXIX76q72A" %}
[ExteriorRing](/docs/server/reference/sql-statements/geometry-constructors/polygon-properties/polygon-properties-exteriorring.md)
{% endcontent-ref %}
{% endcolumn %}

{% column %}
Synonym for ST\_ExteriorRing. Returns the exterior ring of a Polygon as a LineString.
{% endcolumn %}
{% endcolumns %}

{% columns %}
{% column %}
{% content-ref url="/pages/zc9XEyNsUOKMe9y2lhcC" %}
[InteriorRingN](/docs/server/reference/sql-statements/geometry-constructors/polygon-properties/polygon-properties-interiorringn.md)
{% endcontent-ref %}
{% endcolumn %}

{% column %}
Synonym for ST\_InteriorRingN. Returns the N-th interior ring of a Polygon as a LineString.
{% endcolumn %}
{% endcolumns %}

{% columns %}
{% column %}
{% content-ref url="/pages/kQ3rXdqJsGJoXxZ35RKg" %}
[NumInteriorRings](/docs/server/reference/sql-statements/geometry-constructors/polygon-properties/polygon-properties-numinteriorrings.md)
{% endcontent-ref %}
{% endcolumn %}

{% column %}
Synonym for ST\_NumInteriorRings. Returns the number of interior rings in a Polygon geometry.
{% endcolumn %}
{% endcolumns %}

{% columns %}
{% column %}
{% content-ref url="/pages/bhesOUqlg3IzfrRQdSmC" %}
[ST\_AREA](/docs/server/reference/sql-statements/geometry-constructors/polygon-properties/st_area.md)
{% endcontent-ref %}
{% endcolumn %}

{% column %}
Returns the area of a Polygon or MultiPolygon. The result is a double-precision number measured in the geometry's spatial reference units.
{% endcolumn %}
{% endcolumns %}

{% columns %}
{% column %}
{% content-ref url="/pages/G2RhrX28GcygJOa2MJti" %}
[ST\_CENTROID](/docs/server/reference/sql-statements/geometry-constructors/polygon-properties/st_centroid.md)
{% endcontent-ref %}
{% endcolumn %}

{% column %}
Returns the centroid of a Polygon or MultiPolygon. The result is a Point geometry representing the mathematical center of mass.
{% endcolumn %}
{% endcolumns %}

{% columns %}
{% column %}
{% content-ref url="/pages/5jwotcxsenZpN26P9dUq" %}
[ST\_ExteriorRing](/docs/server/reference/sql-statements/geometry-constructors/polygon-properties/st_exteriorring.md)
{% endcontent-ref %}
{% endcolumn %}

{% column %}
Returns the exterior ring of a Polygon. This function extracts the outer boundary of the polygon as a LineString geometry.
{% endcolumn %}
{% endcolumns %}

{% columns %}
{% column %}
{% content-ref url="/pages/Zo3UkFEi3JLSZ31exHbY" %}
[ST\_InteriorRingN](/docs/server/reference/sql-statements/geometry-constructors/polygon-properties/st_interiorringn.md)
{% endcontent-ref %}
{% endcolumn %}

{% column %}
Returns the N-th interior ring of a Polygon. This function retrieves a specific inner hole of the polygon as a LineString.
{% endcolumn %}
{% endcolumns %}

{% columns %}
{% column %}
{% content-ref url="/pages/lGMtMs4rgGlfBX7AvJNZ" %}
[ST\_NumInteriorRings](/docs/server/reference/sql-statements/geometry-constructors/polygon-properties/st_numinteriorrings.md)
{% endcontent-ref %}
{% endcolumn %}

{% column %}
Returns the count of interior rings in a Polygon. This function calculates the total number of inner holes within the polygon.
{% endcolumn %}
{% endcolumns %}