The ST_GEOGFROMTEXT function converts a string in Well-Known Text (WKT) format to a geography object.
Syntax
GEOGRAPHY ST_GEOGFROMTEXT(STRING <WKT>)Parameters
WKT: Required. A string in WKT format. This function does not support the Z (elevation) or M (measure) dimensions. For more information, see GEOGRAPHY data type.
Return value
Returns a geography object. The system validates the input by internally converting it to an S2 geography library object.
The S2 geography library uses the DOUBLE data type to represent the coordinates of a geography object. This conversion can cause minor precision loss, resulting in slight differences between the input and output.
Examples
SELECT ST_GEOGFROMTEXT('POINT (10 20)');
-- Result:
+---------------+
| _c0 |
+---------------+
| POINT (10 20) |
+---------------+
SELECT ST_GEOGFROMTEXT('POINT EMPTY');
-- Result:
+--------------------------+
| _c0 |
+--------------------------+
| GEOMETRYCOLLECTION EMPTY |
+--------------------------+
SELECT ST_GEOGFROMTEXT('LINESTRING (10 20, 30 50, 70 80)');
-- Result:
+----------------------------------+
| _c0 |
+----------------------------------+
| LINESTRING (10 20, 30 50, 70 80) |
+----------------------------------+
SELECT ST_GEOGFROMTEXT('POLYGON ((-10 -10, 10 -10, 10 10, -10 10, -10 -10), (-5 -5, 5 -5, 5 5, -5 5, -5 -5))');
-- Result:
+--------------------------------------------------------------------------------------+
| _c0 |
+--------------------------------------------------------------------------------------+
| POLYGON ((-10 -10, 10 -10, 10 10, -10 10, -10 -10), (-5 -5, 5 -5, 5 5, -5 5, -5 -5)) |
+--------------------------------------------------------------------------------------+