import math


def get_degree_radius(lat, radius_m):
    """
    Calculates a degree radius equivalent to 2*radius_m
    that accounts for the latitude.
    """
    #WGS84 equatorial radius in m
    R = 6378137.0
    m_per_deg_eq = R*math.pi/180.0
    m_per_deg_lat = m_per_deg_eq * math.cos(lat*math.pi/180.0)
    return (2*radius_m)/m_per_deg_lat