ST_AZIMUTH

Syntax

DOUBLE ST_Azimuth(GEOPOINT point1, GEOPOINT point2)

description

Enter two point, and returns the azimuth of the line segment formed by points 1 and 2. The azimuth is the angle in radians measured between the line from point 1 facing true North to the line segment from point 1 to point 2.

The positive angle is measured clockwise on the surface of a sphere. For example, the azimuth for a line segment:

Pointing North is 0
Pointing East is PI/2
Pointing South is PI
Pointing West is 3PI/2

ST_Azimuth has the following edge cases:

If the two input points are the same, returns NULL.
If the two input points are exactly antipodal, returns NULL.
If either of the input geographies are not single points or are the empty geography, throws an error.

example

mysql> SELECT st_azimuth(ST_Point(1, 0),ST_Point(0, 0));
+----------------------------------------------------+
| st_azimuth(st_point(1.0, 0.0), st_point(0.0, 0.0)) |
+----------------------------------------------------+
|                                   4.71238898038469 |
+----------------------------------------------------+
1 row in set (0.03 sec)

mysql> SELECT st_azimuth(ST_Point(0, 0),ST_Point(1, 0));
+----------------------------------------------------+
| st_azimuth(st_point(0.0, 0.0), st_point(1.0, 0.0)) |
+----------------------------------------------------+
|                                 1.5707963267948966 |
+----------------------------------------------------+
1 row in set (0.01 sec)

mysql> SELECT st_azimuth(ST_Point(0, 0),ST_Point(0, 1));
+----------------------------------------------------+
| st_azimuth(st_point(0.0, 0.0), st_point(0.0, 1.0)) |
+----------------------------------------------------+
|                                                  0 |
+----------------------------------------------------+
1 row in set (0.01 sec)

mysql> SELECT st_azimuth(ST_Point(0, 1),ST_Point(0, 1));
+----------------------------------------------------+
| st_azimuth(st_point(0.0, 1.0), st_point(0.0, 1.0)) |
+----------------------------------------------------+
|                                               NULL |
+----------------------------------------------------+
1 row in set (0.02 sec)

mysql> SELECT st_azimuth(ST_Point(-30, 0),ST_Point(150, 0));
+--------------------------------------------------------+
| st_azimuth(st_point(-30.0, 0.0), st_point(150.0, 0.0)) |
+--------------------------------------------------------+
|                                                   NULL |
+--------------------------------------------------------+
1 row in set (0.02 sec)

keywords

ST_AZIMUTH,ST,AZIMUTH

ST_ASTEXT,ST_ASWKT ST_CIRCLE