.. _pylab_examples-tricontour_vs_griddata:

pylab_examples example code: tricontour_vs_griddata.py
======================================================



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

::

    """
    Comparison of griddata and tricontour for an unstructured triangular grid.
    """
    from __future__ import print_function
    import matplotlib.pyplot as plt
    import matplotlib.tri as tri
    import numpy as np
    from numpy.random import uniform, seed
    from matplotlib.mlab import griddata
    import time
    
    seed(0)
    npts = 200
    ngridx = 100
    ngridy = 200
    x = uniform(-2,2,npts)
    y = uniform(-2,2,npts)
    z = x*np.exp(-x**2-y**2)
    
    # griddata and contour.
    start = time.clock()
    plt.subplot(211)
    xi = np.linspace(-2.1,2.1,ngridx)
    yi = np.linspace(-2.1,2.1,ngridy)
    zi = griddata(x,y,z,xi,yi,interp='linear')
    plt.contour(xi,yi,zi,15,linewidths=0.5,colors='k')
    plt.contourf(xi,yi,zi,15,cmap=plt.cm.rainbow,
                 norm=plt.normalize(vmax=abs(zi).max(), vmin=-abs(zi).max()))
    plt.colorbar() # draw colorbar
    plt.plot(x, y, 'ko', ms=3)
    plt.xlim(-2,2)
    plt.ylim(-2,2)
    plt.title('griddata and contour (%d points, %d grid points)' % (npts, ngridx*ngridy))
    print ('griddata and contour seconds: %f' % (time.clock() - start))
    
    # tricontour.
    start = time.clock()
    plt.subplot(212)
    triang = tri.Triangulation(x, y)
    plt.tricontour(x, y, z, 15, linewidths=0.5, colors='k')
    plt.tricontourf(x, y, z, 15, cmap=plt.cm.rainbow,
                    norm=plt.normalize(vmax=abs(zi).max(), vmin=-abs(zi).max()))
    plt.colorbar()
    plt.plot(x, y, 'ko', ms=3)
    plt.xlim(-2,2)
    plt.ylim(-2,2)
    plt.title('tricontour (%d points)' % npts)
    print ('tricontour seconds: %f' % (time.clock() - start))
    
    plt.show()
    

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