.. _pylab_examples-griddata_demo:

pylab_examples example code: griddata_demo.py
=============================================



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

::

    from numpy.random import uniform, seed
    from matplotlib.mlab import griddata
    import matplotlib.pyplot as plt
    import numpy as np
    # make up data.
    #npts = int(raw_input('enter # of random points to plot:'))
    seed(0)
    npts = 200
    x = uniform(-2, 2, npts)
    y = uniform(-2, 2, npts)
    z = x*np.exp(-x**2 - y**2)
    # define grid.
    xi = np.linspace(-2.1, 2.1, 100)
    yi = np.linspace(-2.1, 2.1, 200)
    # grid the data.
    zi = griddata(x, y, z, xi, yi, interp='linear')
    # contour the gridded data, plotting dots at the nonuniform data points.
    CS = plt.contour(xi, yi, zi, 15, linewidths=0.5, colors='k')
    CS = plt.contourf(xi, yi, zi, 15,
                      vmax=abs(zi).max(), vmin=-abs(zi).max())
    plt.colorbar()  # draw colorbar
    # plot data points.
    plt.scatter(x, y, marker='o', s=5, zorder=10)
    plt.xlim(-2, 2)
    plt.ylim(-2, 2)
    plt.title('griddata test (%d points)' % npts)
    plt.show()
    

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