code: def dimap_V(D, I):
      
  # GET CARTESIAN COMPONENTS OF INPUT DIRECTION
      DI = np.array([D, I]).transpose()
      X = dir2cart(DI).transpose()
  # CALCULATE THE X,Y COORDINATES FOR THE EQUAL AREA PROJECTION
      # from Collinson 1983
      R = np.sqrt(1. - abs(X[2]))/(np.sqrt(X[0]**2 + X[1]**2))
      XY = np.array([X[1] * R, X[0] * R]).transpose()
  
  # RETURN XY[X,Y]
      return XY
docs: FUNCTION TO MAP DECLINATION, INCLINATIONS INTO EQUAL AREA PROJECTION, X,Y
  
      Usage:     dimap_V(D, I)
          D and I are both numpy arrays