ST_LineExtend — Returns a line extended forwards and backwards by specified distances.
geometry
ST_LineExtend
(
geometry
line
, float
distance_forward
, float
distance_backward=0.0
)
;
Returns a line extended forwards and backwards by adding new start (and end) points at the given distance(s). A distance of zero does not add a point. Only non-negative distances are allowed. The direction(s) of the added point(s) is determined by the first (and last) two distinct points of the line. Duplicate points are ignored.
Availability: 3.4.0
SELECT ST_AsText(ST_LineExtend('LINESTRING(0 0, 0 10)'::geometry, 5, 6));
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LINESTRING(0 -6,0 0,0 10,0 15)