code: def equi_basemap(m, centerlon, centerlat, radius, color):
      
      glon1 = centerlon
      glat1 = centerlat
      X = []
      Y = []
      for azimuth in range(0, 360):
          glon2, glat2, baz = shoot(glon1, glat1, azimuth, radius)
          X.append(glon2)
          Y.append(glat2)
      X.append(X[0])
      Y.append(Y[0])
  
      X, Y = m(X, Y)
      plt.plot(X, Y, color)
docs: This function enables A95 error ellipses to be drawn in basemap around
      paleomagnetic poles in conjunction with shoot
      (from: http://www.geophysique.be/2011/02/20/matplotlib-basemap-tutorial-09-drawing-circles/).