ST_AddMeasure
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## Name

ST_AddMeasure — Interpolates measures along a linear geometry.

## Synopsis

`geometry ST_AddMeasure(`geometry geom_mline, float8 measure_start, float8 measure_end`)`;

## Description

Return a derived geometry with measure values linearly interpolated between the start and end points. If the geometry has no measure dimension, one is added. If the geometry has a measure dimension, it is over-written with new values. Only LINESTRINGS and MULTILINESTRINGS are supported.

Availability: 1.5.0

This function supports 3d and will not drop the z-index.

## Examples

    SELECT ST_AsText(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_AsText(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)

    SELECT ST_AsText(ST_AddMeasure(
    ST_GeomFromEWKT('LINESTRINGM(1 0 4, 2 0 4, 4 0 4)'),10,40)) As ewelev;
                     ewelev
    ----------------------------------------
     LINESTRINGM(1 0 10,2 0 20,4 0 40)

    SELECT ST_AsText(ST_AddMeasure(
    ST_GeomFromEWKT('MULTILINESTRINGM((1 0 4, 2 0 4, 4 0 4),(1 0 4, 2 0 4, 4 0 4))'),10,70)) As ewelev;
                                 ewelev
    -----------------------------------------------------------------
     MULTILINESTRINGM((1 0 10,2 0 20,4 0 40),(1 0 40,2 0 50,4 0 70))

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