ST_Angle — Returns the angle between two vectors defined by 3 or 4 points, or 2 lines.

`float `

geometry **ST_Angle**(`point1`, geometry `point2`, geometry `point3`, geometry `point4``)`

;

`float `

geometry **ST_Angle**(`line1`, geometry `line2``)`

;

Computes the clockwise angle between two vectors.

**Variant 1:** computes the angle enclosed by the points P1-P2-P3. If a 4th point provided computes the angle points P1-P2 and P3-P4

**Variant 2:** computes the angle between two vectors S1-E1 and S2-E2,
defined by the start and end points of the input lines

The result is a positive angle between 0 and 2π radians.
The radian result can be converted to degrees using the PostgreSQL function `degrees()`

.

Note that `ST_Angle(P1,P2,P3) = ST_Angle(P2,P1,P2,P3)`

.

Availability: 2.5.0

Angle between three points

SELECT degrees( ST_Angle('POINT(0 0)', 'POINT(10 10)', 'POINT(20 0)') ); degrees --------- 270

Angle between vectors defined by four points

SELECT degrees( ST_Angle('POINT (10 10)', 'POINT (0 0)', 'POINT(90 90)', 'POINT (100 80)') ); degrees ------------------- 269.9999999999999

Angle between vectors defined by the start and end points of lines

SELECT degrees( ST_Angle('LINESTRING(0 0, 0.3 0.7, 1 1)', 'LINESTRING(0 0, 0.2 0.5, 1 0)') ); degrees -------------- 45