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

.. only:: html

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

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

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

.. _sphx_glr_gallery_gridlines_and_labels_map_latitudes.py:


Aligning Cartopy and Matplotlib axes
====================================

Sometimes it is useful to line up a standard Matplotlib axes with a Cartopy map, for
example when plotting zonal mean data next to a global contour plot.  This example
demonstrates one way to do that for projections where latitude lines are horizontal.

.. GENERATED FROM PYTHON SOURCE LINES 10-83



.. rst-class:: sphx-glr-horizontal


    *

      .. image-sg:: /gallery/gridlines_and_labels/images/sphx_glr_map_latitudes_001.png
         :alt: PlateCarree
         :srcset: /gallery/gridlines_and_labels/images/sphx_glr_map_latitudes_001.png
         :class: sphx-glr-single-img

    *

      .. image-sg:: /gallery/gridlines_and_labels/images/sphx_glr_map_latitudes_002.png
         :alt: Mercator
         :srcset: /gallery/gridlines_and_labels/images/sphx_glr_map_latitudes_002.png
         :class: sphx-glr-single-img

    *

      .. image-sg:: /gallery/gridlines_and_labels/images/sphx_glr_map_latitudes_003.png
         :alt: Robinson
         :srcset: /gallery/gridlines_and_labels/images/sphx_glr_map_latitudes_003.png
         :class: sphx-glr-single-img





.. code-block:: Python


    # sphinx_gallery_multi_image = "single"

    import matplotlib.pyplot as plt
    import numpy as np

    import cartopy.crs as ccrs


    PC_PROJ = ccrs.PlateCarree()

    def map_and_latitudes(map_proj):
        """
        Create a map with the given projection, together with a rectangular axes
        whose y-axis matches the map.
        """

        fig = plt.figure(figsize=(12, 5), layout='compressed')

        # Create the map.
        map_ax = fig.add_subplot(projection=map_proj)
        map_ax.set_global()
        gl = map_ax.gridlines(draw_labels=True)
        map_ax.coastlines()

        # Add the rectangular axes to the right of the map.
        rect_ax = map_ax.inset_axes([1.1, 0, 0.3, 1])

        # Set up scaling for the rectangular axes latitudes.  This part is
        # necessary for projections with uneven latitude spacing, such as Mercator,
        # but can be skipped for PlateCarree for example.
        # Create functions to map between latitude and the projection's y values.
        # Assume these are not x-dependent so we can just set x/longitude to zero.

        def to_map(lat):
            """Transform latitudes to projection's y-values."""
            dummy_lon = np.zeros_like(lat)
            projected = map_proj.transform_points(PC_PROJ, dummy_lon, lat)
            return np.take(projected, 1, axis=-1)

        def from_map(y):
            """Transform projection's y-values to latitude."""
            dummy_x = np.zeros_like(y)
            projected = PC_PROJ.transform_points(map_proj, dummy_x, y)
            return np.take(projected, 1, axis=-1)

        # Use these function to define the y-scale on the rectangular axes.
        rect_ax.set_yscale('function', functions=(to_map, from_map))
        # Convert the map's y-limits to latitudes and set the y-limits.
        rect_ax.set_ylim(from_map(np.array(map_ax.get_ylim())))

        # y-axis visual choices.
        rect_ax.grid(axis='y')
        rect_ax.yaxis.tick_right()
        rect_ax.yaxis.set_major_locator(gl.ylocator)
        rect_ax.yaxis.set_major_formatter(gl.yformatter)

        # Plot some dummy data.
        y = np.linspace(-90, 90, 21)
        y_rad = np.deg2rad(y)
        rect_ax.plot(np.sin(y_rad), y, label='sine')
        rect_ax.plot(np.cos(y_rad), y, label='cosine')
        rect_ax.legend()

        # Add the projection name as the title.
        fig.suptitle(type(map_proj).__name__)


    if __name__ == '__main__':
        for map_proj in [ccrs.PlateCarree(), ccrs.Mercator(), ccrs.Robinson()]:
            map_and_latitudes(map_proj)

        plt.show()


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

   **Total running time of the script:** (0 minutes 3.344 seconds)


.. _sphx_glr_download_gallery_gridlines_and_labels_map_latitudes.py:

.. only:: html

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

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

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

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

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

    .. container:: sphx-glr-download sphx-glr-download-zip

      :download:`Download zipped: map_latitudes.zip <map_latitudes.zip>`


.. only:: html

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

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