ST_Segmentize
Prev | 8.5. Geometry Editors | Next

## Name

ST_Segmentize — Return a modified geometry/geography having no segment longer than the given distance.

## Synopsis

`geometry ST_Segmentize(`geometry geom, float max_segment_length`)`;

`geography ST_Segmentize(`geography geog, float max_segment_length`)`;

## Description

Returns a modified geometry having no segment longer than the given `max_segment_length`. Distance computation is performed in 2d only. For geometry, length units are in units of spatial reference. For geography, units are in meters.

Availability: 1.2.2

Enhanced: 3.0.0 Segmentize geometry now uses equal length segments

Enhanced: 2.3.0 Segmentize geography now uses equal length segments

Enhanced: 2.1.0 support for geography was introduced.

Changed: 2.1.0 As a result of the introduction of geography support: The construct `SELECT ST_Segmentize('LINESTRING(1 2, 3 4)',0.5);` will result in ambiguous function error. You need to have properly typed object e.g. a geometry/geography column, use ST_GeomFromText, ST_GeogFromText or `SELECT ST_Segmentize('LINESTRING(1 2, 3 4)'::geometry,0.5);`

This will only increase segments. It will not lengthen segments shorter than max length

## Examples

    SELECT ST_AsText(ST_Segmentize(
    ST_GeomFromText('MULTILINESTRING((-29 -27,-30 -29.7,-36 -31,-45 -33),(-45 -33,-46 -32))')
    		,5)
    );
    st_astext
    --------------------------------------------------------------------------------------------------
    MULTILINESTRING((-29 -27,-30 -29.7,-34.886615700134 -30.758766735029,-36 -31,
    -40.8809353009198 -32.0846522890933,-45 -33),
    (-45 -33,-46 -32))
    (1 row)

    SELECT ST_AsText(ST_Segmentize(ST_GeomFromText('POLYGON((-29 28, -30 40, -29 28))'),10));
    st_astext
    -----------------------
    POLYGON((-29 28,-29.8304547985374 37.9654575824488,-30 40,-29.1695452014626 30.0345424175512,-29 28))
    (1 row)

## See Also

ST_LineSubstring

Prev | Up | Next
ST_Reverse | Home | ST_SetPoint