Name
ST_LocateBetweenElevations — Return a derived geometry (collection) value with elements that intersect the specified range of elevations inclusively. Only 3D, 4D LINESTRINGS and MULTILINESTRINGS are supported.
Synopsis
geometry ST_LocateBetweenElevations(geometry geom_mline, float8 elevation_start, float8 elevation_end);
Description
Return a derived geometry (collection) value with elements that intersect the specified range of elevations inclusively. Only 3D, 3DM LINESTRINGS and MULTILINESTRINGS are supported.
Availability: 1.4.0
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(
ST_GeomFromEWKT('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(
ST_GeomFromEWKT('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)