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

    Click :ref:`here <sphx_glr_download_gallery_color_colorbar_basics.py>` to download the full example code
.. rst-class:: sphx-glr-example-title

.. _sphx_glr_gallery_color_colorbar_basics.py:


========
Colorbar
========

Use `~.figure.Figure.colorbar` by specifying the mappable object (here
the `~.matplotlib.image.AxesImage` returned by `~.axes.Axes.imshow`)
and the axes to attach the colorbar to.



.. code-block:: python


    import numpy as np
    import matplotlib.pyplot as plt

    # setup some generic data
    N = 37
    x, y = np.mgrid[:N, :N]
    Z = (np.cos(x*0.2) + np.sin(y*0.3))

    # mask out the negative and positive values, respectively
    Zpos = np.ma.masked_less(Z, 0)
    Zneg = np.ma.masked_greater(Z, 0)

    fig, (ax1, ax2) = plt.subplots(figsize=(8, 3), ncols=2)

    # plot just the positive data and save the
    # color "mappable" object returned by ax1.imshow
    pos = ax1.imshow(Zpos, cmap='Blues', interpolation='none')

    # add the colorbar using the figure's method,
    # telling which mappable we're talking about and
    # which axes object it should be near
    fig.colorbar(pos, ax=ax1)

    # repeat everything above for the negative data
    neg = ax2.imshow(Zneg, cmap='Reds_r', interpolation='none')
    fig.colorbar(neg, ax=ax2)

    plt.show()




.. image:: /gallery/color/images/sphx_glr_colorbar_basics_001.png
    :class: sphx-glr-single-img




------------

References
""""""""""

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



.. code-block:: python


    import matplotlib
    matplotlib.axes.Axes.imshow
    matplotlib.pyplot.imshow
    matplotlib.figure.Figure.colorbar
    matplotlib.pyplot.colorbar







.. _sphx_glr_download_gallery_color_colorbar_basics.py:


.. only :: html

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



  .. container:: sphx-glr-download

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



  .. container:: sphx-glr-download

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


.. only:: html

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

    Keywords: matplotlib code example, codex, python plot, pyplot
    `Gallery generated by Sphinx-Gallery
    <https://sphinx-gallery.readthedocs.io>`_