ST_AREA_SQUARE_METERS

Description

Calculates the area of a closed region on the Earth's surface in square meters. The input parameter is a geometric object representing a region on the Earth's surface (such as polygons, circles, polyhedrons, etc.).

For non-closed geometric objects (such as points, line segments), their area is 0; for invalid geometric objects (such as self-intersecting polygons), returns NULL.

Sytax

ST_AREA_SQUARE_METERS( <geo>)

Parameters

Parameter	Description
<geo>	A geometric object on the Earth's surface, supporting closed region types such as GeoPolygon, GeoCircle, and GeoMultiPolygon.

Return value

Returns the area of the region in square meters, of type DOUBLE.

ST_AREA_SQUARE_METERS has the following edge cases:

• If the input parameter is NULL, returns NULL.
• If the input is a non-closed geometric object (such as point GeoPoint, line segment GeoLineString), returns 0.
• If the input geometric object is invalid (such as self-intersecting polygon, unclosed polygon), returns NULL.
• If the input coordinates exceed the longitude/latitude range (longitude [-180, 180], latitude [-90, 90]), returns NULL.

Example

Circular region (circle with a radius of 1 degree)

SELECT ST_Area_Square_Meters(ST_Circle(0, 0, 1));

+-------------------------------------------------+
| st_area_square_meters(st_circle(0.0, 0.0, 1.0)) |
+-------------------------------------------------+
|                              3.1415926535897869 |
+-------------------------------------------------+

Point object (no area)

SELECT ST_Area_Square_Meters(ST_Point(0, 1));

+-------------------------------------------+
| st_area_square_meters(st_point(0.0, 1.0)) |
+-------------------------------------------+
|                                         0 |
+-------------------------------------------+

Line segment object (no area)

SELECT ST_Area_Square_Meters(ST_LineFromText("LINESTRING (1 1, 2 2)"));

+-----------------------------------------------------------------+
| st_area_square_meters(st_linefromtext('LINESTRING (1 1, 2 2)')) |
+-----------------------------------------------------------------+
|                                                               0 |
+-----------------------------------------------------------------+

Simple square region (small longitude/latitude range)

mysql> SELECT ST_Area_Square_Meters(ST_Polygon("POLYGON ((0 0, 1 0, 1 1, 0 1, 0 0))"));
+--------------------------------------------------------------------------+
| ST_Area_Square_Meters(ST_Polygon("POLYGON ((0 0, 1 0, 1 1, 0 1, 0 0))")) |
+--------------------------------------------------------------------------+
|                                                       12364036567.076408 |
+--------------------------------------------------------------------------+

Complex polygon region

mysql> SELECT ST_Area_Square_Meters(ST_Polygon("POLYGON ((0 0, 5 1, 10 0, 5 -1, 0 0))"));
+----------------------------------------------------------------------------+
| ST_Area_Square_Meters(ST_Polygon("POLYGON ((0 0, 5 1, 10 0, 5 -1, 0 0))")) |
+----------------------------------------------------------------------------+
|                                                         123725166420.83101 |
+----------------------------------------------------------------------------+

Rectangular region crossing 180° longitude

mysql> SELECT ST_Area_Square_Meters(ST_Polygon("POLYGON ((179 0, 180 0, 180 1, 179 1, 179 0))"));
+------------------------------------------------------------------------------------+
| ST_Area_Square_Meters(ST_Polygon("POLYGON ((179 0, 180 0, 180 1, 179 1, 179 0))")) |
+------------------------------------------------------------------------------------+
|                                                                  12364036567.07628 |
+------------------------------------------------------------------------------------+

Circular region in the Southern Hemisphere

mysql> SELECT ST_Area_Square_Meters(ST_Circle(0, -30, 2));
+---------------------------------------------+
| ST_Area_Square_Meters(ST_Circle(0, -30, 2)) |
+---------------------------------------------+
|                          12.566370614359073 |
+---------------------------------------------+

Invalid polygon (self-intersecting)

mysql>  SELECT ST_Area_Square_Meters(ST_Polygon("POLYGON ((0 0, 1 1, 0 1, 1 0, 0 0))"));
+--------------------------------------------------------------------------+
| ST_Area_Square_Meters(ST_Polygon("POLYGON ((0 0, 1 1, 0 1, 1 0, 0 0))")) |
+--------------------------------------------------------------------------+
|                                                                     NULL |
+--------------------------------------------------------------------------+

Unclosed polygon

mysql> SELECT ST_Area_Square_Meters(ST_Polygon("POLYGON ((0 0, 1 0, 1 1, 0 1))"));
+---------------------------------------------------------------------+
| ST_Area_Square_Meters(ST_Polygon("POLYGON ((0 0, 1 0, 1 1, 0 1))")) |
+---------------------------------------------------------------------+
|                                                                NULL |
+---------------------------------------------------------------------+

Coordinates out of range

mysql>  SELECT ST_Area_Square_Meters(ST_Polygon("POLYGON ((0 0, 200 0, 200 1, 0 1, 0 0))"));
+------------------------------------------------------------------------------+
| ST_Area_Square_Meters(ST_Polygon("POLYGON ((0 0, 200 0, 200 1, 0 1, 0 0))")) |
+------------------------------------------------------------------------------+
|                                                                         NULL |
+------------------------------------------------------------------------------+

Null input

mysql> SELECT ST_Area_Square_Meters(NULL);
+-----------------------------+
| ST_Area_Square_Meters(NULL) |
+-----------------------------+
|                        NULL |
+-----------------------------+