clouddrift.sphere.position_from_distance_and_bearing

clouddrift.sphere.position_from_distance_and_bearing#

clouddrift.sphere.position_from_distance_and_bearing(lon: float, lat: float, distance: float, bearing: float) Tuple[float, float][source]#

Return elementwise new position in degrees from arrays of latitude and longitude in degrees, distance in meters, and bearing in radians, based on the spherical law of cosines.

The formula is:

φ2 = asin( sin φ1 ⋅ cos δ + cos φ1 ⋅ sin δ ⋅ cos θ ) λ2 = λ1 + atan2( sin θ ⋅ sin δ ⋅ cos φ1, cos δ − sin φ1 ⋅ sin φ2 )

where (φ, λ) is (lat, lon) and θ is bearing, all in radians. Bearing is defined as zero toward East and positive counterclockwise.

Parameters#

lonfloat

Longitude of the first set of points, in degrees

latfloat

Latitude of the first set of points, in degrees

distancearray_like

Distance in meters

bearingarray_like

Bearing angles in radians

Returns#

lon2array_like

Latitudes of the second set of points, in degrees, in the range [-90, 90]

lat2array_like

Longitudes of the second set of points, in degrees, in the range [-180, 180]

Examples#

Calculate the position of one degree longitude distance on the equator:

>>> position_from_distance_and_bearing(0, 0, 111318.84502145034, 0)
(1.0, 0.0)

Calculate the position of one degree latitude distance from 45 degrees North latitude:

>>> position_from_distance_and_bearing(0, 45, 111318.84502145034, np.pi / 2)
(8.81429402840006e-17, 45.99999999999999)