Represents direction in the coordinate reference system. In a 2D coordinate reference system,
this can be accomplished using a "angle measured from true north" or a 2D vector point in that
direction. In a 3D coordinate reference system, two angles or any 3D vector is possible. If both
a set of angles and a vector are given, then they shall be consistent with one another.
Returns the azimuth and (optionnaly) the altitude. In this variant of bearing usually used
for 2D coordinate systems, the first angle (azimuth) is measured from the first coordinate
axis (usually north) in a counterclockwise fashion parallel to the reference surface tangent
plane. If two angles are given, the second angle (altitude) usually represents the angle
above (for positive angles) or below (for negative angles) a local plane parallel to the
tangent plane of the reference surface.
An array of length 0, 1 or 2 containing the azimuth and altitude angles.