## Name

ST_MaxDistance — Returns the 2D largest distance between two geometries in
projected units.

## Synopsis

`float `**ST_MaxDistance**(

geometry `g1`, geometry `g2``)`

;

## Description

Returns the 2-dimensional maximum distance between two geometries, in projected units.
The maximum distance always occurs between two vertices.
This is the length of the line returned by ST_LongestLine.

If g1 and g2 are the same geometry, returns the distance between
the two vertices farthest apart in that geometry.

Availability: 1.5.0

## Examples

Maximum distance between a point and lines.

SELECT ST_MaxDistance('POINT(0 0)'::geometry, 'LINESTRING ( 2 0, 0 2 )'::geometry);
-----------------
2
SELECT ST_MaxDistance('POINT(0 0)'::geometry, 'LINESTRING ( 2 2, 2 2 )'::geometry);
------------------
2.82842712474619

Maximum distance between vertices of a single geometry.

SELECT ST_MaxDistance('POLYGON ((10 10, 10 0, 0 0, 10 10))'::geometry,
'POLYGON ((10 10, 10 0, 0 0, 10 10))'::geometry);
------------------
14.142135623730951