Converts angle to distance by multiplying angle with radius.
Calculates the distances km in a sphere with radius (also in kilometers) for the angles rad. If unspecified, radius defaults to 6371, the mean radius of Earth.
Alternatively, sphere can be one of "sun", "mercury", "venus", "earth", "moon", "mars", "jupiter", "saturn", "uranus", "neptune", or "pluto", in which case radius will be set to that object mean radius.
See also: deg2km, deg2sm, km2rad, km2deg, nm2deg, nm2rad, rad2km, rad2nm, rad2sm, sm2deg, sm2rad.
Package: mapping