.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "gallery/plot_global_map.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_map.py>`
        to download the full example code

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

.. _sphx_glr_gallery_plot_global_map.py:


Create a Global Map
===================

This script creates a map of the radial magnetic field from the CHAOS
geomagnetic field model at the core surface in 2016. The map projections are
handled by the Cartopy package, which you need to install in addition to
ChaosMagPy to execute the script.

.. GENERATED FROM PYTHON SOURCE LINES 11-73



.. image-sg:: /gallery/images/sphx_glr_plot_global_map_001.png
   :alt: plot global map
   :srcset: /gallery/images/sphx_glr_plot_global_map_001.png
   :class: sphx-glr-single-img





.. code-block:: Python


    # Copyright (C) 2024 Clemens Kloss
    #
    # This script is free software: you can redistribute it and/or modify it under
    # the terms of the GNU Lesser General Public License as published by the Free
    # Software Foundation, either version 3 of the License, or (at your option) any
    # later version.
    #
    # This script is distributed in the hope that it will be useful, but WITHOUT
    # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
    # FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
    # details.
    #
    # You should have received a copy of the GNU Lesser General Public License
    # along with this script. If not, see <https://www.gnu.org/licenses/>.

    import chaosmagpy as cp
    import numpy as np
    import matplotlib.pyplot as plt
    import cartopy.crs as ccrs

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

    time = cp.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 magnetic field from CHAOS up to degree 13
    Br, _, _ = model.synth_values_tdep(time, radius, theta, phi,
                                       nmax=13, deriv=0, grid=True)

    limit = 1.0  # mT colorbar limit

    # create figure
    fig, ax = plt.subplots(1, 1, subplot_kw={'projection': ccrs.EqualEarth()},
                           figsize=(12, 8))

    fig.subplots_adjust(
        top=0.981,
        bottom=0.019,
        left=0.013,
        right=0.987,
        hspace=0.0,
        wspace=1.0
    )

    pc = ax.pcolormesh(phi, 90. - theta, Br/1e6, cmap='PuOr', vmin=-limit,
                       vmax=limit, transform=ccrs.PlateCarree())

    ax.gridlines(linewidth=0.5, linestyle='dashed', color='grey',
                 ylocs=np.linspace(-90, 90, num=7),  # parallels
                 xlocs=np.linspace(-180, 180, num=13))  # meridians

    ax.coastlines(linewidth=0.8, color='k')

    # create colorbar
    clb = plt.colorbar(pc, ax=ax, extend='both', shrink=0.8, pad=0.05,
                       orientation='horizontal')
    clb.set_label('$B_r$ (mT)', fontsize=14)

    plt.show()


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

   **Total running time of the script:** (0 minutes 3.983 seconds)


.. _sphx_glr_download_gallery_plot_global_map.py:

.. only:: html

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

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

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

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

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


.. only:: html

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

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