def plot_net(fignum):
    """
    Draws circle and tick marks for equal area projection.
    """

# make the perimeter
    plt.figure(num=fignum,)
    plt.clf()
    plt.axis("off")
    Dcirc = np.arange(0, 361.)
    Icirc = np.zeros(361, 'f')
    Xcirc, Ycirc = [], []
    for k in range(361):
        XY = pmag.dimap(Dcirc[k], Icirc[k])
        Xcirc.append(XY[0])
        Ycirc.append(XY[1])
    plt.plot(Xcirc, Ycirc, 'k')

# put on the tick marks
    Xsym, Ysym = [], []
    for I in range(10, 100, 10):
        XY = pmag.dimap(0., I)
        Xsym.append(XY[0])
        Ysym.append(XY[1])
    plt.plot(Xsym, Ysym, 'k+')
    Xsym, Ysym = [], []
    for I in range(10, 90, 10):
        XY = pmag.dimap(90., I)
        Xsym.append(XY[0])
        Ysym.append(XY[1])
    plt.plot(Xsym, Ysym, 'k+')
    Xsym, Ysym = [], []
    for I in range(10, 90, 10):
        XY = pmag.dimap(180., I)
        Xsym.append(XY[0])
        Ysym.append(XY[1])
    plt.plot(Xsym, Ysym, 'k+')
    Xsym, Ysym = [], []
    for I in range(10, 90, 10):
        XY = pmag.dimap(270., I)
        Xsym.append(XY[0])
        Ysym.append(XY[1])
    plt.plot(Xsym, Ysym, 'k+')
    for D in range(0, 360, 10):
        Xtick, Ytick = [], []
        for I in range(4):
            XY = pmag.dimap(D, I)
            Xtick.append(XY[0])
            Ytick.append(XY[1])
        plt.plot(Xtick, Ytick, 'k')
    plt.axis("equal")
    plt.axis((-1.05, 1.05, -1.05, 1.05))
Draws circle and tick marks for equal area projection.