.. _pylab_examples-contour_label_demo:

pylab_examples example code: contour_label_demo.py
==================================================



.. plot:: /home/tcaswell/source/p/matplotlib/doc/mpl_examples/pylab_examples/contour_label_demo.py

::

    #!/usr/bin/env python
    """
    Illustrate some of the more advanced things that one can do with
    contour labels.
    
    See also contour_demo.py.
    """
    import matplotlib
    import numpy as np
    import matplotlib.cm as cm
    import matplotlib.mlab as mlab
    import matplotlib.ticker as ticker
    import matplotlib.pyplot as plt
    
    matplotlib.rcParams['xtick.direction'] = 'out'
    matplotlib.rcParams['ytick.direction'] = 'out'
    
    ##################################################
    # Define our surface
    ##################################################
    delta = 0.025
    x = np.arange(-3.0, 3.0, delta)
    y = np.arange(-2.0, 2.0, delta)
    X, Y = np.meshgrid(x, y)
    Z1 = mlab.bivariate_normal(X, Y, 1.0, 1.0, 0.0, 0.0)
    Z2 = mlab.bivariate_normal(X, Y, 1.5, 0.5, 1, 1)
    # difference of Gaussians
    Z = 10.0 * (Z2 - Z1)
    
    ##################################################
    # Make contour labels using creative float classes
    # Follows suggestion of Manuel Metz
    ##################################################
    plt.figure()
    
    # Basic contour plot
    CS = plt.contour(X, Y, Z)
    
    
    # Define a class that forces representation of float to look a certain way
    # This remove trailing zero so '1.0' becomes '1'
    class nf(float):
        def __repr__(self):
            str = '%.1f' % (self.__float__(),)
            if str[-1] == '0':
                return '%.0f' % self.__float__()
            else:
                return '%.1f' % self.__float__()
    
    # Recast levels to new class
    CS.levels = [nf(val) for val in CS.levels]
    
    # Label levels with specially formatted floats
    if plt.rcParams["text.usetex"]:
        fmt = r'%r \%%'
    else:
        fmt = '%r %%'
    plt.clabel(CS, CS.levels, inline=True, fmt=fmt, fontsize=10)
    
    ##################################################
    # Label contours with arbitrary strings using a
    # dictionary
    ##################################################
    plt.figure()
    
    # Basic contour plot
    CS = plt.contour(X, Y, Z)
    
    fmt = {}
    strs = ['first', 'second', 'third', 'fourth', 'fifth', 'sixth', 'seventh']
    for l, s in zip(CS.levels, strs):
        fmt[l] = s
    
    # Label every other level using strings
    plt.clabel(CS, CS.levels[::2], inline=True, fmt=fmt, fontsize=10)
    
    # Use a Formatter
    
    plt.figure()
    
    CS = plt.contour(X, Y, 100**Z, locator=plt.LogLocator())
    fmt = ticker.LogFormatterMathtext()
    fmt.create_dummy_axis()
    plt.clabel(CS, CS.levels, fmt=fmt)
    plt.title("$100^Z$")
    
    plt.show()
    

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