geo_angle()

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Calculates clockwise angle in radians between two lines on Earth. The first line is [point1, point2] and the second line is [point2, point3].

Syntax

geo_angle(p1_longitude,p1_latitude,p2_longitude,p2_latitude,p3_longitude,p3_latitude)

Learn more about syntax conventions.

Parameters

Name Type Required Description
p1_longitude real ✔️ The longitude value in degrees of the first geospatial coordinate. A valid value is in the range [-180, +180].
p1_latitude real ✔️ The latitude value in degrees of the first geospatial coordinate. A valid value is in the range [-90, +90].
p2_longitude real ✔️ The longitude value in degrees of the second geospatial coordinate. A valid value is in the range [-180, +180].
p2_latitude real ✔️ The latitude value in degrees of the second geospatial coordinate. A valid value is in the range [-90, +90].
p3_longitude real ✔️ The longitude value in degrees of the second geospatial coordinate. A valid value is in the range [-180, +180].
p3_latitude real ✔️ The latitude value in degrees of the second geospatial coordinate. A valid value is in the range [-90, +90].

Returns

An angle in radians in range [0, 2pi) between two lines [p1, p2] and [p2, p3]. The angle is measured CW from the first line to the Second line.

Note

  • The geospatial coordinates are interpreted as represented by the WGS-84 coordinate reference system.
  • The geodetic datum used to measure distance on Earth is a sphere. Line edges are geodesics on the sphere.
  • If the coordinates are invalid, the query will produce a null result.
  • If point1 is equal to point2, the query will produce a null result.
  • If point2 is equal to point3, the query will produce a null result.
  • If point1 and point2 are antipodal, the query will produce a null result.
  • If point2 and point3 are antipodal, the query will produce a null result.

Examples

The following example calculates the angle in radians.

Run the query

print angle_in_radians = geo_angle(0, 10, 0,5, 3,-10)

Output

angle_in_radians
2.94493843406882

The following example calculates the angle in degrees.

Run the query

let angle_in_radians = geo_angle(0, 10, 0,5, 3,-10);
print angle_in_degrees = degrees(angle_in_radians)

Output

angle_in_degrees
168.732543198009

The following example returns null because 1st point equals to 2nd point.

Run the query

print is_null = isnull(geo_angle(0, 10, 0, 10, 3, -10))

Output

is_null
True