# chaosmagpy.coordinate_utils.basevectors_use¶

chaosmagpy.coordinate_utils.basevectors_use(theta, phi)[source]

Computes the unit base vectors of local orthogonal coordinate system USE (Up-South-East) on the spherical surface (theta, phi) with respect to the standard geographic coordinate system (GEO).

Parameters:
thetandarray, shape (…)

Geocentric colatitude in degrees $$(0^\circ, 180^\circ)$$, i.e. exclude poles.

phindarray, shape (…)

Geocentric longitude in degrees.

Returns:
use_1, use_2, use_3ndarray, shape (…, 3)

USE unit base vectors. The leading dimension agrees with the shape of theta or phi, while the last dimension contains the unit vector components in terms of GEO.