.. _pylab_examples-broken_axis: pylab_examples example code: broken_axis.py =========================================== .. plot:: /home/tcaswell/source/p/matplotlib/doc/mpl_examples/pylab_examples/broken_axis.py :: """ Broken axis example, where the y-axis will have a portion cut out. """ import matplotlib.pyplot as plt import numpy as np # 30 points between [0, 0.2) originally made using np.random.rand(30)*.2 pts = np.array([ 0.015, 0.166, 0.133, 0.159, 0.041, 0.024, 0.195, 0.039, 0.161, 0.018, 0.143, 0.056, 0.125, 0.096, 0.094, 0.051, 0.043, 0.021, 0.138, 0.075, 0.109, 0.195, 0.050, 0.074, 0.079, 0.155, 0.020, 0.010, 0.061, 0.008]) # Now let's make two outlier points which are far away from everything. pts[[3, 14]] += .8 # If we were to simply plot pts, we'd lose most of the interesting # details due to the outliers. So let's 'break' or 'cut-out' the y-axis # into two portions - use the top (ax) for the outliers, and the bottom # (ax2) for the details of the majority of our data f, (ax, ax2) = plt.subplots(2, 1, sharex=True) # plot the same data on both axes ax.plot(pts) ax2.plot(pts) # zoom-in / limit the view to different portions of the data ax.set_ylim(.78, 1.) # outliers only ax2.set_ylim(0, .22) # most of the data # hide the spines between ax and ax2 ax.spines['bottom'].set_visible(False) ax2.spines['top'].set_visible(False) ax.xaxis.tick_top() ax.tick_params(labeltop='off') # don't put tick labels at the top ax2.xaxis.tick_bottom() # This looks pretty good, and was fairly painless, but you can get that # cut-out diagonal lines look with just a bit more work. The important # thing to know here is that in axes coordinates, which are always # between 0-1, spine endpoints are at these locations (0,0), (0,1), # (1,0), and (1,1). Thus, we just need to put the diagonals in the # appropriate corners of each of our axes, and so long as we use the # right transform and disable clipping. d = .015 # how big to make the diagonal lines in axes coordinates # arguments to pass to plot, just so we don't keep repeating them kwargs = dict(transform=ax.transAxes, color='k', clip_on=False) ax.plot((-d, +d), (-d, +d), **kwargs) # top-left diagonal ax.plot((1 - d, 1 + d), (-d, +d), **kwargs) # top-right diagonal kwargs.update(transform=ax2.transAxes) # switch to the bottom axes ax2.plot((-d, +d), (1 - d, 1 + d), **kwargs) # bottom-left diagonal ax2.plot((1 - d, 1 + d), (1 - d, 1 + d), **kwargs) # bottom-right diagonal # What's cool about this is that now if we vary the distance between # ax and ax2 via f.subplots_adjust(hspace=...) or plt.subplot_tool(), # the diagonal lines will move accordingly, and stay right at the tips # of the spines they are 'breaking' plt.show() Keywords: python, matplotlib, pylab, example, codex (see :ref:`how-to-search-examples`)