.. _pylab_examples-polar_demo:

pylab_examples example code: polar_demo.py
==========================================



.. plot:: /home/mdboom/Work/builds/matplotlib/doc/mpl_examples/pylab_examples/polar_demo.py

::

    #!/usr/bin/env python
    #
    # matplotlib now has a PolarAxes class and a polar function in the
    # matplotlib interface.  This is considered alpha and the interface
    # may change as we work out how polar axes should best be integrated
    #
    # The only function that has been tested on polar axes is "plot" (the
    # pylab interface function "polar" calls ax.plot where ax is a
    # PolarAxes) -- other axes plotting functions may work on PolarAxes
    # but haven't been tested and may need tweaking.
    #
    # you can get a PolarSubplot instance by doing, for example
    #
    #   subplot(211, polar=True)
    #
    # or a PolarAxes instance by doing
    #   axes([left, bottom, width, height], polar=True)
    #
    # The view limits (eg xlim and ylim) apply to the lower left and upper
    # right of the rectangular box that surrounds to polar axes.  Eg if
    # you have
    #
    #  r = arange(0,1,0.01)
    #  theta = 2*pi*r
    #
    # the lower left corner is 5/4pi, sqrt(2) and the
    # upper right corner is 1/4pi, sqrt(2)
    #
    # you could change the radial bounding box (zoom out) by setting the
    # ylim (radial coordinate is the second argument to the plot command,
    # as in MATLAB, though this is not advised currently because it is not
    # clear to me how the axes should behave in the change of view limits.
    # Please advise me if you have opinions.  Likewise, the pan/zoom
    # controls probably do not do what you think they do and are better
    # left alone on polar axes.  Perhaps I will disable them for polar
    # axes unless we come up with a meaningful, useful and functional
    # implementation for them.
    #
    # See the pylab rgrids and thetagrids functions for
    # information on how to customize the grid locations and labels
    import matplotlib
    import numpy as np
    from matplotlib.pyplot import figure, show, rc, grid
    
    # radar green, solid grid lines
    rc('grid', color='#316931', linewidth=1, linestyle='-')
    rc('xtick', labelsize=15)
    rc('ytick', labelsize=15)
    
    # force square figure and square axes looks better for polar, IMO
    width, height = matplotlib.rcParams['figure.figsize']
    size = min(width, height)
    # make a square figure
    fig = figure(figsize=(size, size))
    ax = fig.add_axes([0.1, 0.1, 0.8, 0.8], polar=True, axisbg='#d5de9c')
    
    r = np.arange(0, 3.0, 0.01)
    theta = 2*np.pi*r
    ax.plot(theta, r, color='#ee8d18', lw=3)
    ax.set_rmax(2.0)
    grid(True)
    
    ax.set_title("And there was much rejoicing!", fontsize=20)
    show()
    

Keywords: python, matplotlib, pylab, example, codex (see :ref:`how-to-search-examples`)