.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "gallery/images_contours_and_fields/quadmesh_demo.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

    .. meta::
        :keywords: codex

    .. note::
        :class: sphx-glr-download-link-note

        :ref:`Go to the end <sphx_glr_download_gallery_images_contours_and_fields_quadmesh_demo.py>`
        to download the full example code

.. rst-class:: sphx-glr-example-title

.. _sphx_glr_gallery_images_contours_and_fields_quadmesh_demo.py:


=============
QuadMesh Demo
=============

`~.axes.Axes.pcolormesh` uses a `~matplotlib.collections.QuadMesh`,
a faster generalization of `~.axes.Axes.pcolor`, but with some restrictions.

This demo illustrates a bug in quadmesh with masked data.

.. GENERATED FROM PYTHON SOURCE LINES 11-44

.. code-block:: Python


    import numpy as np

    from matplotlib import pyplot as plt

    n = 12
    x = np.linspace(-1.5, 1.5, n)
    y = np.linspace(-1.5, 1.5, n * 2)
    X, Y = np.meshgrid(x, y)
    Qx = np.cos(Y) - np.cos(X)
    Qz = np.sin(Y) + np.sin(X)
    Z = np.sqrt(X**2 + Y**2) / 5
    Z = (Z - Z.min()) / (Z.max() - Z.min())

    # The color array can include masked values.
    Zm = np.ma.masked_where(np.abs(Qz) < 0.5 * np.max(Qz), Z)

    fig, axs = plt.subplots(nrows=1, ncols=3)
    axs[0].pcolormesh(Qx, Qz, Z, shading='gouraud')
    axs[0].set_title('Without masked values')

    # You can control the color of the masked region.
    cmap = plt.colormaps[plt.rcParams['image.cmap']].with_extremes(bad='y')
    axs[1].pcolormesh(Qx, Qz, Zm, shading='gouraud', cmap=cmap)
    axs[1].set_title('With masked values')

    # Or use the default, which is transparent.
    axs[2].pcolormesh(Qx, Qz, Zm, shading='gouraud')
    axs[2].set_title('With masked values')

    fig.tight_layout()
    plt.show()




.. image-sg:: /gallery/images_contours_and_fields/images/sphx_glr_quadmesh_demo_001.png
   :alt: Without masked values, With masked values, With masked values
   :srcset: /gallery/images_contours_and_fields/images/sphx_glr_quadmesh_demo_001.png, /gallery/images_contours_and_fields/images/sphx_glr_quadmesh_demo_001_2_00x.png 2.00x
   :class: sphx-glr-single-img





.. GENERATED FROM PYTHON SOURCE LINES 45-51

.. admonition:: References

   The use of the following functions, methods, classes and modules is shown
   in this example:

   - `matplotlib.axes.Axes.pcolormesh` / `matplotlib.pyplot.pcolormesh`


.. rst-class:: sphx-glr-timing

   **Total running time of the script:** (0 minutes 1.122 seconds)


.. _sphx_glr_download_gallery_images_contours_and_fields_quadmesh_demo.py:

.. only:: html

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

    .. container:: sphx-glr-download sphx-glr-download-jupyter

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

    .. container:: sphx-glr-download sphx-glr-download-python

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


.. only:: html

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

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