ST_LocateAlong
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Name

ST_LocateAlong — Returns the point(s) on a geometry that match a measure value.

Synopsis

geometry ST_LocateAlong(geometry geom_with_measure, float8 measure, float8 offset = 0);

Descrizione

Returns the location(s) along a measured geometry that have the given measure values. The result is a Point or MultiPoint. Polygonal inputs are not supported.

If offset is provided, the result is offset to the left or right of the input line by the specified distance. A positive offset will be to the left, and a negative one to the right.

[Note]

Use this function only for linear geometries with an M component

The semantic is specified by the ISO/IEC 13249-3 SQL/MM Spatial standard.

Availability: 1.1.0 by old name ST_Locate_Along_Measure.

Changed: 2.0.0 in prior versions this used to be called ST_Locate_Along_Measure.

Questa funzione supporta le coordinate M.

Questo metodo implementa la specifica SQL/MM. SQL-MM IEC 13249-3: 5.1.13

Esempi

SELECT ST_AsText(
  ST_LocateAlong(
    'MULTILINESTRINGM((1 2 3, 3 4 2, 9 4 3),(1 2 3, 5 4 5))'::geometry,
    3 ));

----------------------------------
 MULTIPOINT M ((1 2 3),(9 4 3),(1 2 3))