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

.. only:: html

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

        Click :ref:`here <sphx_glr_download_gallery_images_contours_and_fields_contour_demo.py>`
        to download the full example code

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

.. _sphx_glr_gallery_images_contours_and_fields_contour_demo.py:


============
Contour Demo
============

Illustrate simple contour plotting, contours on an image with
a colorbar for the contours, and labelled contours.

See also the :doc:`contour image example
</gallery/images_contours_and_fields/contour_image>`.

.. GENERATED FROM PYTHON SOURCE LINES 12-27

.. code-block:: default


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


    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








.. GENERATED FROM PYTHON SOURCE LINES 28-31

Create a simple contour plot with labels using default colors.  The inline
argument to clabel will control whether the labels are draw over the line
segments of the contour, removing the lines beneath the label.

.. GENERATED FROM PYTHON SOURCE LINES 31-37

.. code-block:: default


    fig, ax = plt.subplots()
    CS = ax.contour(X, Y, Z)
    ax.clabel(CS, inline=True, fontsize=10)
    ax.set_title('Simplest default with labels')




.. image:: /gallery/images_contours_and_fields/images/sphx_glr_contour_demo_001.png
    :alt: Simplest default with labels
    :class: sphx-glr-single-img


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

 Out:

 .. code-block:: none


    Text(0.5, 1.0, 'Simplest default with labels')



.. GENERATED FROM PYTHON SOURCE LINES 38-41

Contour labels can be placed manually by providing list of positions (in data
coordinate).  See :doc:`/gallery/event_handling/ginput_manual_clabel_sgskip`
for interactive placement.

.. GENERATED FROM PYTHON SOURCE LINES 41-49

.. code-block:: default


    fig, ax = plt.subplots()
    CS = ax.contour(X, Y, Z)
    manual_locations = [
        (-1, -1.4), (-0.62, -0.7), (-2, 0.5), (1.7, 1.2), (2.0, 1.4), (2.4, 1.7)]
    ax.clabel(CS, inline=True, fontsize=10, manual=manual_locations)
    ax.set_title('labels at selected locations')




.. image:: /gallery/images_contours_and_fields/images/sphx_glr_contour_demo_002.png
    :alt: labels at selected locations
    :class: sphx-glr-single-img


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

 Out:

 .. code-block:: none


    Text(0.5, 1.0, 'labels at selected locations')



.. GENERATED FROM PYTHON SOURCE LINES 50-51

You can force all the contours to be the same color.

.. GENERATED FROM PYTHON SOURCE LINES 51-57

.. code-block:: default


    fig, ax = plt.subplots()
    CS = ax.contour(X, Y, Z, 6, colors='k')  # Negative contours default to dashed.
    ax.clabel(CS, fontsize=9, inline=True)
    ax.set_title('Single color - negative contours dashed')




.. image:: /gallery/images_contours_and_fields/images/sphx_glr_contour_demo_003.png
    :alt: Single color - negative contours dashed
    :class: sphx-glr-single-img


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

 Out:

 .. code-block:: none


    Text(0.5, 1.0, 'Single color - negative contours dashed')



.. GENERATED FROM PYTHON SOURCE LINES 58-59

You can set negative contours to be solid instead of dashed:

.. GENERATED FROM PYTHON SOURCE LINES 59-66

.. code-block:: default


    matplotlib.rcParams['contour.negative_linestyle'] = 'solid'
    fig, ax = plt.subplots()
    CS = ax.contour(X, Y, Z, 6, colors='k')  # Negative contours default to dashed.
    ax.clabel(CS, fontsize=9, inline=True)
    ax.set_title('Single color - negative contours solid')




.. image:: /gallery/images_contours_and_fields/images/sphx_glr_contour_demo_004.png
    :alt: Single color - negative contours solid
    :class: sphx-glr-single-img


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

 Out:

 .. code-block:: none


    Text(0.5, 1.0, 'Single color - negative contours solid')



.. GENERATED FROM PYTHON SOURCE LINES 67-68

And you can manually specify the colors of the contour

.. GENERATED FROM PYTHON SOURCE LINES 68-77

.. code-block:: default


    fig, ax = plt.subplots()
    CS = ax.contour(X, Y, Z, 6,
                    linewidths=np.arange(.5, 4, .5),
                    colors=('r', 'green', 'blue', (1, 1, 0), '#afeeee', '0.5'),
                    )
    ax.clabel(CS, fontsize=9, inline=True)
    ax.set_title('Crazy lines')




.. image:: /gallery/images_contours_and_fields/images/sphx_glr_contour_demo_005.png
    :alt: Crazy lines
    :class: sphx-glr-single-img


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

 Out:

 .. code-block:: none


    Text(0.5, 1.0, 'Crazy lines')



.. GENERATED FROM PYTHON SOURCE LINES 78-80

Or you can use a colormap to specify the colors; the default
colormap will be used for the contour lines

.. GENERATED FROM PYTHON SOURCE LINES 80-112

.. code-block:: default


    fig, ax = plt.subplots()
    im = ax.imshow(Z, interpolation='bilinear', origin='lower',
                   cmap=cm.gray, extent=(-3, 3, -2, 2))
    levels = np.arange(-1.2, 1.6, 0.2)
    CS = ax.contour(Z, levels, origin='lower', cmap='flag', extend='both',
                    linewidths=2, extent=(-3, 3, -2, 2))

    # Thicken the zero contour.
    zc = CS.collections[6]
    plt.setp(zc, linewidth=4)

    ax.clabel(CS, levels[1::2],  # label every second level
              inline=True, fmt='%1.1f', fontsize=14)

    # make a colorbar for the contour lines
    CB = fig.colorbar(CS, shrink=0.8)

    ax.set_title('Lines with colorbar')

    # We can still add a colorbar for the image, too.
    CBI = fig.colorbar(im, orientation='horizontal', shrink=0.8)

    # This makes the original colorbar look a bit out of place,
    # so let's improve its position.

    l, b, w, h = ax.get_position().bounds
    ll, bb, ww, hh = CB.ax.get_position().bounds
    CB.ax.set_position([ll, b + 0.1*h, ww, h*0.8])

    plt.show()




.. image:: /gallery/images_contours_and_fields/images/sphx_glr_contour_demo_006.png
    :alt: Lines with colorbar
    :class: sphx-glr-single-img





.. GENERATED FROM PYTHON SOURCE LINES 113-120

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

References
""""""""""

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

.. GENERATED FROM PYTHON SOURCE LINES 121-131

.. code-block:: default


    import matplotlib
    matplotlib.axes.Axes.contour
    matplotlib.pyplot.contour
    matplotlib.figure.Figure.colorbar
    matplotlib.pyplot.colorbar
    matplotlib.axes.Axes.clabel
    matplotlib.pyplot.clabel
    matplotlib.axes.Axes.set_position
    matplotlib.axes.Axes.get_position




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

 Out:

 .. code-block:: none


    <function _AxesBase.get_position at 0x7fcc1641bb80>




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

   **Total running time of the script:** ( 0 minutes  2.273 seconds)


.. _sphx_glr_download_gallery_images_contours_and_fields_contour_demo.py:


.. only :: html

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



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

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



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

     :download:`Download Jupyter notebook: contour_demo.ipynb <contour_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>`_