ST_Segmentize-PolarDB(PolarDB)-阿里云帮助中心

Returns a modified geometry or geography object in which no segment is longer than the specified maximum length.

Syntax

geometry  ST_Segmentize(geometry geom, float maxSegmentLength);
geography ST_Segmentize(geography geog, float maxSegmentLength);

Parameter	Description
`geom`	The input geometry object.
`geog`	The input geography object.
`maxSegmentLength`	The maximum allowed segment length. For geometry inputs, the unit follows the spatial reference of the input. For geography inputs, the unit is meters.

LINESTRING — basic segmentation

The following example splits a line segment of length 1 into two equal subsegments of length 0.5:

SELECT ST_AsText(ST_Segmentize(ST_GeomFromText('LINESTRING(2 1,1 1)'), 0.5));

Output:

         st_astext
---------------------------
 LINESTRING(2 1,1.5 1,1 1)
(1 row)

The midpoint (1.5, 1) is inserted, splitting the original segment into two equal subsegments.