PostGIS 1.5.8 Manual - Fedora Project Packages GIT repositories

PostGIS 1.5.8 Manual244 / 310ST_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 digestableSELECT 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)See AlsoST_Dump7.10.7 ST_AddMeasureST_AddMeasure — Return a derived geometry with measure elements linearly interpolated between the start and end points. Ifthe geometry has no measure dimension, one is added. If the geometry has a measure dimension, it is over-written with newvalues. Only LINESTRINGS and MULTILINESTRINGS are supported.Synopsisgeometry ST_AddMeasure(geometry geom_mline, float measure_start, float measure_end);DescriptionReturn a derived geometry with measure elements linearly interpolated between the start and end points. If the geometry hasno measure dimension, one is added. If the geometry has a measure dimension, it is over-written with new values. OnlyLINESTRINGS and MULTILINESTRINGS are supported.Availability: 1.5.0This function supports 3d and will not drop the z-index.ExamplesSELECT ST_AsEWKT(ST_AddMeasure(ST_GeomFromEWKT(’LINESTRING(1 0, 2 0, 4 0)’),1,4)) As ewelev;ewelev--------------------------------LINESTRINGM(1 0 1,2 0 2,4 0 4)SELECT ST_AsEWKT(ST_AddMeasure(ST_GeomFromEWKT(’LINESTRING(1 0 4, 2 0 4, 4 0 4)’),10,40)) As ewelev;ewelev----------------------------------------LINESTRING(1 0 4 10,2 0 4 20,4 0 4 40)