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

.. only:: html

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

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

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

.. _sphx_glr_gallery_plot_global_polar.py:


Create a Global Map and Polar Views
===================================

Compute a map of the first time-derivative of the radial field component on the
core surface in 2016 using CHAOS.

.. GENERATED FROM PYTHON SOURCE LINES 9-68



.. image-sg:: /gallery/images/sphx_glr_plot_global_polar_001.png
   :alt: plot global polar
   :srcset: /gallery/images/sphx_glr_plot_global_polar_001.png
   :class: sphx-glr-single-img





.. code-block:: default


    import chaosmagpy as cp
    import numpy as np
    import matplotlib.pyplot as plt
    import matplotlib.gridspec as gridspec
    from mpl_toolkits.axes_grid1.inset_locator import inset_axes
    import cartopy.crs as ccrs

    model = cp.CHAOS.from_mat('CHAOS-7.mat')  # load the mat-file of CHAOS-7

    time = cp.data_utils.mjd2000(2016, 1, 1)  # convert date to mjd2000
    radius = 3485.  # radius of the core surface in km
    theta = np.linspace(1., 179., 181)  # colatitude in degrees
    phi = np.linspace(-180., 180, 361)  # longitude in degrees

    # compute radial SV up to degree 16 using CHAOS
    B, _, _ = model.synth_values_tdep(time, radius, theta, phi,
                                      nmax=16, deriv=1, grid=True)

    limit = 30e3  # nT colorbar limit

    # create figure
    fig = plt.figure(figsize=(12, 8))

    fig.subplots_adjust(
        top=0.98,
        bottom=0.02,
        left=0.013,
        right=0.988,
        hspace=0.0,
        wspace=1.0
    )

    # make array of axes
    gs = gridspec.GridSpec(2, 2, width_ratios=[0.5, 0.5], height_ratios=[0.35, 0.65])

    axes = [
        plt.subplot(gs[0, 0], projection=ccrs.NearsidePerspective(central_latitude=90.)),
        plt.subplot(gs[0, 1], projection=ccrs.NearsidePerspective(central_latitude=-90.)),
        plt.subplot(gs[1, :], projection=ccrs.Mollweide())
    ]

    for ax in axes:
        pc = ax.pcolormesh(phi, 90. - theta, B, cmap='PuOr', vmin=-limit,
                           vmax=limit, transform=ccrs.PlateCarree())
        ax.gridlines(linewidth=0.5, linestyle='dashed',
                     ylocs=np.linspace(-90, 90, num=7),  # parallels
                     xlocs=np.linspace(-180, 180, num=13))  # meridians
        ax.coastlines(linewidth=0.5)

    # inset axes into global map and move upwards
    cax = inset_axes(axes[-1], width="45%", height="5%", loc='upper center',
                     borderpad=-12)

    # use last artist for the colorbar
    clb = plt.colorbar(pc, cax=cax, extend='both', orientation='horizontal')
    clb.set_label('nT/yr', fontsize=14)

    plt.show()


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

   **Total running time of the script:** ( 0 minutes  3.277 seconds)


.. _sphx_glr_download_gallery_plot_global_polar.py:

.. only:: html

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




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

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

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

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


.. only:: html

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

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