### Navigation

- index
- modules |
- home|
- examples|
- tutorials|
- pyplot|
- docs »

# Ellipse With Units

Compare the ellipse generated with arcs versus a polygonal approximation

This example requires `basic_units.py`

    from basic_units import cm
    import numpy as np
    from matplotlib import patches
    import matplotlib.pyplot as plt

    xcenter, ycenter = 0.38*cm, 0.52*cm
    width, height = 1e-1*cm, 3e-1*cm
    angle = -30

    theta = np.deg2rad(np.arange(0.0, 360.0, 1.0))
    x = 0.5 * width * np.cos(theta)
    y = 0.5 * height * np.sin(theta)

    rtheta = np.radians(angle)
    R = np.array([
        [np.cos(rtheta), -np.sin(rtheta)],
        [np.sin(rtheta),  np.cos(rtheta)],
        ])

    x, y = np.dot(R, np.array([x, y]))
    x += xcenter
    y += ycenter

    fig = plt.figure()
    ax = fig.add_subplot(211, aspect='auto')
    ax.fill(x, y, alpha=0.2, facecolor='yellow',
            edgecolor='yellow', linewidth=1, zorder=1)

    e1 = patches.Ellipse((xcenter, ycenter), width, height,
                         angle=angle, linewidth=2, fill=False, zorder=2)

    ax.add_patch(e1)

    ax = fig.add_subplot(212, aspect='equal')
    ax.fill(x, y, alpha=0.2, facecolor='green', edgecolor='green', zorder=1)
    e2 = patches.Ellipse((xcenter, ycenter), width, height,
                         angle=angle, linewidth=2, fill=False, zorder=2)

    ax.add_patch(e2)
    fig.savefig('ellipse_compare')

    fig = plt.figure()
    ax = fig.add_subplot(211, aspect='auto')
    ax.fill(x, y, alpha=0.2, facecolor='yellow',
            edgecolor='yellow', linewidth=1, zorder=1)

    e1 = patches.Arc((xcenter, ycenter), width, height,
                     angle=angle, linewidth=2, fill=False, zorder=2)

    ax.add_patch(e1)

    ax = fig.add_subplot(212, aspect='equal')
    ax.fill(x, y, alpha=0.2, facecolor='green', edgecolor='green', zorder=1)
    e2 = patches.Arc((xcenter, ycenter), width, height,
                     angle=angle, linewidth=2, fill=False, zorder=2)

    ax.add_patch(e2)
    fig.savefig('arc_compare')

    plt.show()

Total running time of the script: ( 0 minutes 0.274 seconds)

Generated by Sphinx-Gallery