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A POINT
is a sizeless location identified by its X and Y coordinates. These coordinates are then translated according to the current spatial reference system (denoted by an SRID) to determine what the Point "is", or what it "means" relative to the other spatial objects (if any) in the data set.
Examples
SQL
A Point can be created in SQL by the st_point
function.
The statement below creates a Point (using the common SRID 4326).
SELECT ST_SetSRID(ST_Makepoint(0,0), 4326);
st_setsrid
------------------------------------------------------
0101000020E610000000000000000000000000000000000000
(1 row)
Well known text
A Point can be created from SQL by calling the st_geomfromtext
function on a Point definition expressed in the Well Known Text (WKT) format as shown below.
SELECT ST_GeomFromText('POINT(0 0)');
st_geomfromtext
----------------------------------------------
010100000000000000000000000000000000000000
(1 row)