Kategorien:: Geodatenfunktionen

ST_AREA¶

Returns the area of the Polygon(s) in a GEOGRAPHY or GEOMETRY object.

Syntax¶

ST_AREA( <geography_or_geometry_expression> )

Argumente¶

geography_expression: The argument must be of type GEOGRAPHY or GEOMETRY.

Rückgabewerte¶

Returns a REAL value, which represents the area:

For GEOGRAPHY input values, the area is in square meters.
For GEOMETRY input values, the area is computed with the same units used to define the input coordinates.

Nutzungshinweise¶

Wenn geography_expression weder ein Polygon noch ein MultiPolygon oder eine GeometryCollection ist, die Polygone enthält, gibt ST_AREA den Wert 0 zurück.
Wenn geography_expression eine GeometryCollection ist, gibt ST_AREA die Summe der Flächen der Polygone in der Collection zurück.

Beispiele¶

GEOGRAPHY Examples¶

This uses the ST_AREA function with GEOGRAPHY objects to calculate the area of Earth’s surface 1 degree on each side with the bottom of the area on the equator:

SELECT ST_AREA(TO_GEOGRAPHY('POLYGON((0 0, 1 0, 1 1, 0 1, 0 0))')) AS area;
+------------------+
|             AREA |
|------------------|
| 12364036567.0764 |
+------------------+

GEOMETRY Examples¶

The following example calls the ST_AREA function with GEOMETRY objects that represent a Point, LineString, and Polygon.

SELECT ST_AREA(g), ST_ASWKT(g)
FROM (SELECT TO_GEOMETRY(column1) as g
  from values ('POINT(1 1)'),
              ('LINESTRING(0 0, 1 1)'),
              ('POLYGON((0 0, 0 1, 1 1, 1 0, 0 0))'));

+------------+--------------------------------+
| ST_AREA(G) | ST_ASWKT(G)                    |
|------------+--------------------------------|
|          0 | POINT(1 1)                     |
|          0 | LINESTRING(0 0,1 1)            |
|          1 | POLYGON((0 0,0 1,1 1,1 0,0 0)) |
+------------+--------------------------------+