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

.. only:: html

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

        Click :ref:`here <sphx_glr_download_gallery_britain-magnetic.py>`
        to download the full example code

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

.. _sphx_glr_gallery_britain-magnetic.py:


Magnetic airborne survey of Britain
-----------------------------------

This is a digitization of an airborne magnetic survey of Britain. Data are
sampled where flight lines crossed contours on the archive maps. Contains
only the total field magnetic anomaly, not the magnetic field intensity
measurements or corrections.

Unfortunately, the exact date of measurements is not available (only the year).

Contains British Geological Survey materials © UKRI 2021.

**Original source:**
`British Geological Survey
<https://www.bgs.ac.uk/datasets/gb-aeromagnetic-survey/>`__

.. GENERATED FROM PYTHON SOURCE LINES 25-31

.. code-block:: default

    import numpy as np
    import pandas as pd
    import pygmt

    import ensaio








.. GENERATED FROM PYTHON SOURCE LINES 32-33

Download and cache the data and return the path to it on disk

.. GENERATED FROM PYTHON SOURCE LINES 33-36

.. code-block:: default

    fname = ensaio.fetch_britain_magnetic(version=1)
    print(fname)





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

 Out:

 .. code-block:: none

    /home/runner/work/_temp/cache/ensaio/v1/britain-magnetic.csv.xz




.. GENERATED FROM PYTHON SOURCE LINES 37-38

Load the CSV formatted data with pandas

.. GENERATED FROM PYTHON SOURCE LINES 38-41

.. code-block:: default

    data = pd.read_csv(fname)
    data






.. raw:: html

    <div class="output_subarea output_html rendered_html output_result">
    <div>
    <style scoped>
        .dataframe tbody tr th:only-of-type {
            vertical-align: middle;
        }

        .dataframe tbody tr th {
            vertical-align: top;
        }

        .dataframe thead th {
            text-align: right;
        }
    </style>
    <table border="1" class="dataframe">
      <thead>
        <tr style="text-align: right;">
          <th></th>
          <th>line_and_segment</th>
          <th>year</th>
          <th>longitude</th>
          <th>latitude</th>
          <th>height_m</th>
          <th>total_field_anomaly_nt</th>
        </tr>
      </thead>
      <tbody>
        <tr>
          <th>0</th>
          <td>FL1-1</td>
          <td>1955</td>
          <td>-1.74162</td>
          <td>53.48164</td>
          <td>792</td>
          <td>62</td>
        </tr>
        <tr>
          <th>1</th>
          <td>FL1-1</td>
          <td>1955</td>
          <td>-1.70122</td>
          <td>53.48352</td>
          <td>663</td>
          <td>56</td>
        </tr>
        <tr>
          <th>2</th>
          <td>FL1-1</td>
          <td>1955</td>
          <td>-1.08051</td>
          <td>53.47677</td>
          <td>315</td>
          <td>30</td>
        </tr>
        <tr>
          <th>3</th>
          <td>FL1-1</td>
          <td>1955</td>
          <td>-1.07471</td>
          <td>53.47672</td>
          <td>315</td>
          <td>31</td>
        </tr>
        <tr>
          <th>4</th>
          <td>FL1-1</td>
          <td>1955</td>
          <td>-1.01763</td>
          <td>53.47586</td>
          <td>321</td>
          <td>44</td>
        </tr>
        <tr>
          <th>...</th>
          <td>...</td>
          <td>...</td>
          <td>...</td>
          <td>...</td>
          <td>...</td>
          <td>...</td>
        </tr>
        <tr>
          <th>541503</th>
          <td>FL-3(TL10-24)-1</td>
          <td>1965</td>
          <td>-4.68843</td>
          <td>58.26786</td>
          <td>1031</td>
          <td>64</td>
        </tr>
        <tr>
          <th>541504</th>
          <td>FL-3(TL10-24)-1</td>
          <td>1965</td>
          <td>-4.68650</td>
          <td>58.26786</td>
          <td>1045</td>
          <td>74</td>
        </tr>
        <tr>
          <th>541505</th>
          <td>FL-3(TL10-24)-1</td>
          <td>1965</td>
          <td>-4.68535</td>
          <td>58.26790</td>
          <td>1035</td>
          <td>94</td>
        </tr>
        <tr>
          <th>541506</th>
          <td>FL-3(TL10-24)-1</td>
          <td>1965</td>
          <td>-4.68419</td>
          <td>58.26787</td>
          <td>1024</td>
          <td>114</td>
        </tr>
        <tr>
          <th>541507</th>
          <td>FL-3(TL10-24)-1</td>
          <td>1965</td>
          <td>-4.68274</td>
          <td>58.26790</td>
          <td>1011</td>
          <td>120</td>
        </tr>
      </tbody>
    </table>
    <p>541508 rows × 6 columns</p>
    </div>
    </div>
    <br />
    <br />

.. GENERATED FROM PYTHON SOURCE LINES 42-44

Make a PyGMT map with the data points colored by the total field magnetic
anomaly.

.. GENERATED FROM PYTHON SOURCE LINES 44-60

.. code-block:: default


    fig = pygmt.Figure()
    scale = np.percentile(data.total_field_anomaly_nt, 95)
    pygmt.makecpt(cmap="polar", series=[-scale, scale])
    fig.plot(
        x=data.longitude,
        y=data.latitude,
        style="c0.02c",
        color=data.total_field_anomaly_nt,
        cmap=True,
        projection="M15c",
    )
    fig.colorbar(frame='af+l"nT"', position="jBL+h+w7c/0.2c+o1/2")
    fig.coast(shorelines=True)
    fig.basemap(frame="afg")
    fig.show()



.. image-sg:: /gallery/images/sphx_glr_britain-magnetic_001.png
   :alt: britain magnetic
   :srcset: /gallery/images/sphx_glr_britain-magnetic_001.png
   :class: sphx-glr-single-img


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

 Out:

 .. code-block:: none

    <IPython.core.display.Image object>





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

   **Total running time of the script:** ( 0 minutes  21.924 seconds)


.. _sphx_glr_download_gallery_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>`_