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

.. only:: html

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

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

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

.. _sphx_glr_sample_data_britain_magnetic.py:


Total Field Magnetic Anomaly from Great Britain
================================================

These data are a complete airborne survey of the entire Great Britain
conducted between 1955 and 1965. The data are made available by the
British Geological Survey (BGS) through their `geophysical data portal
<https://www.bgs.ac.uk/products/geophysics/aeromagneticRegional.html>`__.

License: `Open Government License
<http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/>`__

The columns of the data table are longitude, latitude, total-field
magnetic anomaly (nanoTesla), observation height relative to the WGS84 datum
(in meters), survey area, and line number and line segment for each data point.

Latitude, longitude, and elevation data converted from original OSGB36
(epsg:27700) coordinate system to WGS84 (epsg:4326) using to_crs function in
GeoPandas.

See the original data for more processing information.

If the file isn't already in your data directory, it will be downloaded
automatically.

.. GENERATED FROM PYTHON SOURCE LINES 32-71



.. image:: /sample_data/images/sphx_glr_britain_magnetic_001.png
    :alt: Magnetic data from Great Britain
    :class: sphx-glr-single-img


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

 Out:

 .. code-block:: none

           survey_area line-number-segment  ...  altitude_m  total_field_anomaly_nt
    0       CA55_NORTH               FL1-1  ...       842.0                      62
    1       CA55_NORTH               FL1-1  ...       713.0                      56
    2       CA55_NORTH               FL1-1  ...       364.0                      30
    3       CA55_NORTH               FL1-1  ...       364.0                      31
    4       CA55_NORTH               FL1-1  ...       370.0                      44
    ...            ...                 ...  ...         ...                     ...
    541503        HG65     FL-3(TL10-24)-1  ...      1084.0                      64
    541504        HG65     FL-3(TL10-24)-1  ...      1098.0                      74
    541505        HG65     FL-3(TL10-24)-1  ...      1088.0                      94
    541506        HG65     FL-3(TL10-24)-1  ...      1077.0                     114
    541507        HG65     FL-3(TL10-24)-1  ...      1064.0                     120

    [541508 rows x 6 columns]






|

.. code-block:: default

    import cartopy.crs as ccrs
    import matplotlib.pyplot as plt
    import numpy as np
    import verde as vd

    import harmonica as hm

    # Fetch the data in a pandas.DataFrame
    data = hm.datasets.fetch_britain_magnetic()
    print(data)

    # Plot the observations in a Mercator map using Cartopy
    fig = plt.figure(figsize=(7.5, 10))
    ax = plt.axes(projection=ccrs.Mercator())
    ax.set_title("Magnetic data from Great Britain", pad=25)
    maxabs = np.percentile(data.total_field_anomaly_nt, 99)
    tmp = ax.scatter(
        data.longitude,
        data.latitude,
        c=data.total_field_anomaly_nt,
        s=0.001,
        cmap="seismic",
        vmin=-maxabs,
        vmax=maxabs,
        transform=ccrs.PlateCarree(),
    )
    plt.colorbar(
        tmp,
        ax=ax,
        label="total field magnetic anomaly [nT]",
        orientation="vertical",
        aspect=50,
        shrink=0.7,
        pad=0.1,
    )
    ax.set_extent(vd.get_region((data.longitude, data.latitude)))
    ax.gridlines(draw_labels=True)
    ax.coastlines(resolution="50m")
    plt.show()


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

   **Total running time of the script:** ( 0 minutes  6.046 seconds)


.. _sphx_glr_download_sample_data_britain_magnetic.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: britain_magnetic.py <britain_magnetic.py>`



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

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


.. only:: html

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

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