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

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

.. _sphx_glr_gallery_images_contours_and_fields_contour_label_demo.py:


==================
Contour Label Demo
==================

Illustrate some of the more advanced things that one can do with
contour labels.

See also contour_demo.py.



.. code-block:: python

    import matplotlib
    import numpy as np
    import matplotlib.cm as cm
    import matplotlib.ticker as ticker
    import matplotlib.pyplot as plt

    matplotlib.rcParams['xtick.direction'] = 'out'
    matplotlib.rcParams['ytick.direction'] = 'out'







Define our surface



.. code-block:: python


    delta = 0.025
    x = np.arange(-3.0, 3.0, delta)
    y = np.arange(-2.0, 2.0, delta)
    X, Y = np.meshgrid(x, y)
    Z1 = np.exp(-X**2 - Y**2)
    Z2 = np.exp(-(X - 1)**2 - (Y - 1)**2)
    Z = (Z1 - Z2) * 2







Make contour labels using creative float classes
Follows suggestion of Manuel Metz



.. code-block:: python


    plt.figure()

    # Basic contour plot
    CS = plt.contour(X, Y, Z)


    # Define a class that forces representation of float to look a certain way
    # This remove trailing zero so '1.0' becomes '1'
    class nf(float):
        def __repr__(self):
            str = '%.1f' % (self.__float__(),)
            if str[-1] == '0':
                return '%.0f' % self.__float__()
            else:
                return '%.1f' % self.__float__()


    # Recast levels to new class
    CS.levels = [nf(val) for val in CS.levels]

    # Label levels with specially formatted floats
    if plt.rcParams["text.usetex"]:
        fmt = r'%r \%%'
    else:
        fmt = '%r %%'
    plt.clabel(CS, CS.levels, inline=True, fmt=fmt, fontsize=10)




.. image:: /gallery/images_contours_and_fields/images/sphx_glr_contour_label_demo_001.png
    :class: sphx-glr-single-img




Label contours with arbitrary strings using a dictionary



.. code-block:: python


    plt.figure()

    # Basic contour plot
    CS = plt.contour(X, Y, Z)

    fmt = {}
    strs = ['first', 'second', 'third', 'fourth', 'fifth', 'sixth', 'seventh']
    for l, s in zip(CS.levels, strs):
        fmt[l] = s

    # Label every other level using strings
    plt.clabel(CS, CS.levels[::2], inline=True, fmt=fmt, fontsize=10)




.. image:: /gallery/images_contours_and_fields/images/sphx_glr_contour_label_demo_002.png
    :class: sphx-glr-single-img




Use a Formatter



.. code-block:: python


    plt.figure()

    CS = plt.contour(X, Y, 100**Z, locator=plt.LogLocator())
    fmt = ticker.LogFormatterMathtext()
    fmt.create_dummy_axis()
    plt.clabel(CS, CS.levels, fmt=fmt)
    plt.title("$100^Z$")

    plt.show()



.. image:: /gallery/images_contours_and_fields/images/sphx_glr_contour_label_demo_003.png
    :class: sphx-glr-single-img





.. _sphx_glr_download_gallery_images_contours_and_fields_contour_label_demo.py:


.. only :: html

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



  .. container:: sphx-glr-download

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



  .. container:: sphx-glr-download

     :download:`Download Jupyter notebook: contour_label_demo.ipynb <contour_label_demo.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>`_