This topic describes the ST_AddMeasure function. This function linearly interpolates m coordinates into the specified range of a geometry object and returns a new geometry object.
Syntax
geometry ST_AddMeasure(geometry geomMline , float8 measureStart , float8 measureEnd);
Parameters
Parameter | Description |
---|---|
geomMline | The LineString object that you want to specify. |
measureStart | The minimum m coordinate that is allowed. |
measureEnd | The maximum m coordinate that is allowed. |
Description
- If the geometry object that you specify does not have an m dimension, add an m dimension to the geometry object. If the geometry object that you specify has an m dimension, this function overwrites the original m coordinates with the new m coordinates.
- This function supports only MultiLineString objects.
- This function supports 3D objects and does not delete z coordinates.
Examples
SELECT ST_AsText(ST_AddMeasure('LINESTRING(1 0, 2 0)'::geometry,1,2));
st_astext
----------------------------
LINESTRING M (1 0 1,2 0 2)
(1 row)