EARTH_ROSE direction rose from earth coordinate angles.

Syntax:
EARTH_ROSE(E)
EARTH_ROSE(E, nbins)

Inputs:
E: Angular current direction in degrees, earth coordinates.
OPTIONAL:
nbins: number of bins to plot histogram

Example:
theta = [110 110 110 90 288 290 292];
nbins = 20;
earth_rose(theta, nbins);