NAME:
dl_to_rphi_2d
PURPOSE:
convert Galactic longitude and distance to Galactocentric radius and azimuth
INPUT:
d - distance
l - Galactic longitude [rad/deg if degree]
KEYWORDS:
degree= (False): l is in degrees rather than rad
ro= (1) Galactocentric radius of the observer
phio= (0) Galactocentric azimuth of the observer [rad/deg if degree]
OUTPUT:
(R,phi); phi in degree if degree
HISTORY:
2012-01-04 - Written - Bovy (IAS)