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

1. mysql> SELECT st_azimuth(ST_Point(1, 0),ST_Point(0, 0));
2. +----------------------------------------------------+
3. | st_azimuth(st_point(1.0, 0.0), st_point(0.0, 0.0)) |
4. +----------------------------------------------------+
5. |                                   4.71238898038469 |
6. +----------------------------------------------------+
7. 1 row in set (0.03 sec)

9. mysql> SELECT st_azimuth(ST_Point(0, 0),ST_Point(1, 0));
10. +----------------------------------------------------+
11. | st_azimuth(st_point(0.0, 0.0), st_point(1.0, 0.0)) |
12. +----------------------------------------------------+
13. |                                 1.5707963267948966 |
14. +----------------------------------------------------+
15. 1 row in set (0.01 sec)

17. mysql> SELECT st_azimuth(ST_Point(0, 0),ST_Point(0, 1));
18. +----------------------------------------------------+
19. | st_azimuth(st_point(0.0, 0.0), st_point(0.0, 1.0)) |
20. +----------------------------------------------------+
21. |                                                  0 |
22. +----------------------------------------------------+
23. 1 row in set (0.01 sec)

25. mysql> SELECT st_azimuth(ST_Point(0, 1),ST_Point(0, 1));
26. +----------------------------------------------------+
27. | st_azimuth(st_point(0.0, 1.0), st_point(0.0, 1.0)) |
28. +----------------------------------------------------+
29. |                                               NULL |
30. +----------------------------------------------------+
31. 1 row in set (0.02 sec)

33. mysql> SELECT st_azimuth(ST_Point(-30, 0),ST_Point(150, 0));
34. +--------------------------------------------------------+
35. | st_azimuth(st_point(-30.0, 0.0), st_point(150.0, 0.0)) |
36. +--------------------------------------------------------+
37. |                                                   NULL |
38. +--------------------------------------------------------+
39. 1 row in set (0.02 sec)

keywords

ST_AZIMUTH,ST,AZIMUTH