Name
ST_LocateBetweenElevations — Return a derived geometry (collection) value with elements that intersect the specified range of elevations inclusively.
Synopsis
geometry ST_LocateBetweenElevations(geometry geom, float8 elevation_start, float8 elevation_end);
Description
Return a derived geometry (collection) value with elements that intersect the specified range of elevations inclusively.
Clipping a non-convex POLYGON may produce invalid geometry.
Availability: 1.4.0
Enhanced: 3.0.0 - added support for POLYGON, TIN, TRIANGLE.
This function supports 3d and will not drop the z-index.
Examples
SELECT ST_AsEWKT(ST_LocateBetweenElevations(
ST_GeomFromEWKT('LINESTRING(1 2 3, 4 5 6)'), 2, 4)) As ewelev;
ewelev
----------------------------------------------------------------
MULTILINESTRING((1 2 3,2 3 4))
SELECT ST_AsEWKT(ST_LocateBetweenElevations('LINESTRING(1 2 6, 4 5 -1, 7 8 9)', 6, 9)) As ewelev;
ewelev
----------------------------------------------------------------
GEOMETRYCOLLECTION(POINT(1 2 6),LINESTRING(6.1 7.1 6,7 8 9))
-- Geometry collections are difficult animals so dump them
-- to make them more digestable
SELECT ST_AsEWKT((ST_Dump(the_geom)).geom)
FROM
(SELECT ST_LocateBetweenElevations('LINESTRING(1 2 6, 4 5 -1, 7 8 9)', 6, 9) as the_geom) As foo;
st_asewkt
--------------------------------
POINT(1 2 6)
LINESTRING(6.1 7.1 6,7 8 9)