.. _sphx_glr_gallery_images_contours_and_fields_griddata_demo.py:


=============
Griddata Demo
=============

Example showing plotting of non uniform data points in the form of grid.




.. image:: /gallery/images_contours_and_fields/images/sphx_glr_griddata_demo_001.png
    :align: center





.. code-block:: python

    from matplotlib.mlab import griddata
    import matplotlib.pyplot as plt
    import numpy as np

    # make up data.
    random_state = np.random.RandomState(19680801)

    npts = 200
    x = random_state.uniform(-2, 2, npts)
    y = random_state.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()



.. only :: html

 .. container:: sphx-glr-footer
    :class: sphx-glr-footer-example


  .. container:: binder-badge

    .. image:: https://static.mybinder.org/badge.svg
      :target: https://mybinder.org/v2/gh/choldgraf/matplotlib/gh-pages?filepath=_downloads/griddata_demo.ipynb
      :width: 150 px


  .. container:: sphx-glr-download

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



  .. container:: sphx-glr-download

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


.. only:: html

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

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