Name
ST_StartPoint — Returns the first point of a LINESTRING
geometry as a POINT.
Synopsis
geometry ST_StartPoint(geometry geomA);
Description
Returns the first point of a LINESTRING geometry
as a POINT or NULL if the input
parameter is not a LINESTRING.
This method implements the SQL/MM specification. SQL-MM 3: 7.1.3
This function supports 3d and will not drop the z-index.
Examples
SELECT ST_AsText(ST_StartPoint('LINESTRING(0 1, 0 2)'::geometry));
st_astext
------------
POINT(0 1)
(1 row)
SELECT ST_StartPoint('POINT(0 1)'::geometry) IS NULL AS is_null;
is_null
----------
t
(1 row)
--3d line
SELECT ST_AsEWKT(ST_StartPoint('LINESTRING(0 1 1, 0 2 2)'::geometry));
st_asewkt
------------
POINT(0 1 1)
(1 row)