.. _pylab_examples-poormans_contour:

pylab_examples example code: poormans_contour.py
================================================



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

::

    #!/usr/bin/env python
    """
    Use a pcolor or imshow with a custom colormap to make a contour plot.
    
    Since this example was initially written, a proper contour routine was
    added to matplotlib - see contour_demo.py and
    http://matplotlib.sf.net/matplotlib.pylab.html#-contour.
    """
    
    from pylab import *
    
    
    delta = 0.01
    x = arange(-3.0, 3.0, delta)
    y = arange(-3.0, 3.0, delta)
    X,Y = meshgrid(x, y)
    Z1 = bivariate_normal(X, Y, 1.0, 1.0, 0.0, 0.0)
    Z2 = bivariate_normal(X, Y, 1.5, 0.5, 1, 1)
    Z = Z2 - Z1 # difference of Gaussians
    
    cmap = cm.get_cmap('PiYG', 11)    # 11 discrete colors
    
    im = imshow(Z, cmap=cmap, interpolation='bilinear',
                vmax=abs(Z).max(), vmin=-abs(Z).max())
    axis('off')
    colorbar()
    
    show()
    
    

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