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PostGIS ST_Length() Function

PostGIS ST_Length() returns the 2D length of a linear geometry. For geometry values, the result uses the units of the geometry’s spatial reference system. For geography values, the result is measured in meters by default.

ST_Length() Syntax

This is the syntax of the PostgreSQL length() function:

length(geometric_type) -> double precision

Parameters

geometric_type

Required. It can be lseg, path.

Return value

The PostgreSQL length() function returns the total length of the line segment or path specified by the parameter.

length() Examples

The following statement shows how to use PostgreSQL length() function to calculate the total length of path '[(2,0),(0,0)]'.

SELECT length(path '[(2,0),(0,0)]');

 length
--------
      2

The following statement shows how to use PostgreSQL length() function to calculate the total length of path '((2,0),(0,0))'.

SELECT length(path '((2,0),(0,0))');

 length
--------
      4

The following statement shows how to use PostgreSQL length() function to calculate the total length of lseg '(2,0),(0,0)'.

SELECT length(lseg '(2,0),(0,0)');

 length
--------
      2