This topic describes the ST_MaxDistance function. This function calculates the farthest distance between two geometry objects. The farthest distance is measured in the unit that is specified in the spatial reference system of the geometry objects.
Syntax
float ST_MaxDistance(geometry g1 , geometry g2);Parameters
| Parameter | Description |
|---|---|
| g1 | The first geometry object that you want to specify. |
| g2 | The second geometry object that you want to specify. |
Description
If the first geometry object and second geometry object that you specify are the same, the function returns the distance between the farthest two vertices of the geometry object.
Examples
Calculate the farthest distance between two geometry objects by using the default
parameter settings.
SELECT ST_MaxDistance('LINESTRING (0 0,-1 1)'::geometry, 'LINESTRING (0 0,1 1)'::geometry);
st_maxdistance
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2
(1 row)