

.. _sphx_glr_gallery_images_contours_and_fields_tricontour_vs_griddata.py:


======================
Tricontour Vs Griddata
======================

Comparison of griddata and tricontour for an unstructured triangular grid.




.. image:: /gallery/images_contours_and_fields/images/sphx_glr_tricontour_vs_griddata_001.png
    :align: center


.. rst-class:: sphx-glr-script-out

 Out::

    griddata and contour: 0.218058 seconds
    tricontour: 0.100136 seconds




|


.. code-block:: python

    from __future__ import print_function
    import matplotlib.pyplot as plt
    import matplotlib.tri as tri
    import numpy as np
    import matplotlib.mlab as mlab
    import time

    np.random.seed(0)
    npts = 200
    ngridx = 100
    ngridy = 200
    x = np.random.uniform(-2, 2, npts)
    y = np.random.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 = mlab.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,
                 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: %f seconds' % (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,
                    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: %f seconds' % (time.clock() - start))

    plt.subplots_adjust(hspace=0.5)

    plt.show()

**Total running time of the script:** ( 0 minutes  0.328 seconds)



.. container:: sphx-glr-footer


  .. container:: sphx-glr-download

     :download:`Download Python source code: tricontour_vs_griddata.py <tricontour_vs_griddata.py>`



  .. container:: sphx-glr-download

     :download:`Download Jupyter notebook: tricontour_vs_griddata.ipynb <tricontour_vs_griddata.ipynb>`

.. rst-class:: sphx-glr-signature

    `Generated by Sphinx-Gallery <https://sphinx-gallery.readthedocs.io>`_
