Spine Placement

Adjusting the location and appearance of axis spines.

Note: If you want to obtain arrow heads at the ends of the axes, also check out the Centered spines with arrows example.

import numpy as np
import matplotlib.pyplot as plt

fig = plt.figure()
x = np.linspace(-np.pi, np.pi, 100)
y = 2 * np.sin(x)

ax = fig.add_subplot(2, 2, 1)
ax.set_title('centered spines')
ax.plot(x, y)
ax.spines.left.set_position('center')
ax.spines.right.set_color('none')
ax.spines.bottom.set_position('center')
ax.spines.top.set_color('none')
ax.xaxis.set_ticks_position('bottom')
ax.yaxis.set_ticks_position('left')

ax = fig.add_subplot(2, 2, 2)
ax.set_title('zeroed spines')
ax.plot(x, y)
ax.spines.left.set_position('zero')
ax.spines.right.set_color('none')
ax.spines.bottom.set_position('zero')
ax.spines.top.set_color('none')
ax.xaxis.set_ticks_position('bottom')
ax.yaxis.set_ticks_position('left')

ax = fig.add_subplot(2, 2, 3)
ax.set_title('spines at axes (0.6, 0.1)')
ax.plot(x, y)
ax.spines.left.set_position(('axes', 0.6))
ax.spines.right.set_color('none')
ax.spines.bottom.set_position(('axes', 0.1))
ax.spines.top.set_color('none')
ax.xaxis.set_ticks_position('bottom')
ax.yaxis.set_ticks_position('left')

ax = fig.add_subplot(2, 2, 4)
ax.set_title('spines at data (1, 2)')
ax.plot(x, y)
ax.spines.left.set_position(('data', 1))
ax.spines.right.set_color('none')
ax.spines.bottom.set_position(('data', 2))
ax.spines.top.set_color('none')
ax.xaxis.set_ticks_position('bottom')
ax.yaxis.set_ticks_position('left')

Define a method that adjusts the location of the axis spines

def adjust_spines(ax, spines):
    for loc, spine in ax.spines.items():
        if loc in spines:
            spine.set_position(('outward', 10))  # outward by 10 points
        else:
            spine.set_color('none')  # don't draw spine

    # turn off ticks where there is no spine
    if 'left' in spines:
        ax.yaxis.set_ticks_position('left')
    else:
        # no yaxis ticks
        ax.yaxis.set_ticks([])

    if 'bottom' in spines:
        ax.xaxis.set_ticks_position('bottom')
    else:
        # no xaxis ticks
        ax.xaxis.set_ticks([])

Create another figure using our new adjust_spines method

fig = plt.figure()

x = np.linspace(0, 2 * np.pi, 100)
y = 2 * np.sin(x)

ax = fig.add_subplot(2, 2, 1)
ax.plot(x, y, clip_on=False)
adjust_spines(ax, ['left'])

ax = fig.add_subplot(2, 2, 2)
ax.plot(x, y, clip_on=False)
adjust_spines(ax, [])

ax = fig.add_subplot(2, 2, 3)
ax.plot(x, y, clip_on=False)
adjust_spines(ax, ['left', 'bottom'])

ax = fig.add_subplot(2, 2, 4)
ax.plot(x, y, clip_on=False)
adjust_spines(ax, ['bottom'])

plt.show()