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

.. only:: html

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

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

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

.. _sphx_glr_gallery_transformations_upward_derivative.py:


Upward derivative of a regular grid
===================================

.. GENERATED FROM PYTHON SOURCE LINES 11-73



.. image-sg:: /gallery/transformations/images/sphx_glr_upward_derivative_001.png
   :alt: upward derivative
   :srcset: /gallery/transformations/images/sphx_glr_upward_derivative_001.png
   :class: sphx-glr-single-img


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

 Out:

 .. code-block:: none


    Upward derivative:
     <xarray.DataArray (northing: 370, easting: 346)>
    array([[ 0.95819797,  0.62479631,  0.65249329, ..., -1.73446106,
            -1.67664073, -2.7243531 ],
           [ 0.63634155,  0.21904983,  0.23107703, ..., -0.49049877,
            -0.45948262, -1.68410265],
           [ 0.66359221,  0.23536193,  0.2450619 , ..., -0.51034902,
            -0.49225175, -1.75482593],
           ...,
           [ 3.3946594 ,  0.9299787 ,  0.84907987, ..., -0.18739683,
            -0.37947336, -1.13012159],
           [ 3.28895305,  0.89679032,  0.84612464, ..., -0.15550245,
            -0.36489469, -1.12153511],
           [ 5.04819984,  2.91262219,  2.80733139, ...,  0.11714946,
            -0.38706034, -1.26040298]])
    Coordinates:
      * northing  (northing) float64 7.576e+06 7.576e+06 ... 7.595e+06 7.595e+06
      * easting   (easting) float64 4.655e+05 4.656e+05 ... 4.827e+05 4.828e+05
    <IPython.core.display.Image object>






|

.. code-block:: default

    import ensaio
    import pygmt
    import verde as vd
    import xarray as xr
    import xrft

    import harmonica as hm

    # Fetch magnetic grid over the Lightning Creek Sill Complex, Australia using
    # Ensaio and load it with Xarray
    fname = ensaio.fetch_lightning_creek_magnetic(version=1)
    magnetic_grid = xr.load_dataarray(fname)

    # Pad the grid to increase accuracy of the FFT filter
    pad_width = {
        "easting": magnetic_grid.easting.size // 3,
        "northing": magnetic_grid.northing.size // 3,
    }
    # drop the extra height coordinate
    magnetic_grid_no_height = magnetic_grid.drop_vars("height")
    magnetic_grid_padded = xrft.pad(magnetic_grid_no_height, pad_width)

    # Compute the upward derivative of the grid
    deriv_upward = hm.derivative_upward(magnetic_grid_padded)

    # Unpad the derivative grid
    deriv_upward = xrft.unpad(deriv_upward, pad_width)

    # Show the upward derivative
    print("\nUpward derivative:\n", deriv_upward)


    # Plot original magnetic anomaly and the upward derivative
    fig = pygmt.Figure()
    with fig.subplot(nrows=1, ncols=2, figsize=("28c", "15c"), sharey="l"):
        with fig.set_panel(panel=0):
            # Make colormap of data
            scale = 2500
            pygmt.makecpt(cmap="polar+h", series=[-scale, scale], background=True)
            # Plot magnetic anomaly grid
            fig.grdimage(
                grid=magnetic_grid,
                projection="X?",
                cmap=True,
            )
            # Add colorbar
            fig.colorbar(
                frame='af+l"Magnetic anomaly [nT]"',
                position="JBC+h+o0/1c+e",
            )
        with fig.set_panel(panel=1):
            # Make colormap for upward derivative (saturate it a little bit)
            scale = 0.6 * vd.maxabs(deriv_upward)
            pygmt.makecpt(cmap="polar+h", series=[-scale, scale], background=True)
            # Plot upward derivative
            fig.grdimage(grid=deriv_upward, projection="X?", cmap=True)
            # Add colorbar
            fig.colorbar(
                frame='af+l"Upward derivative [nT/m]"',
                position="JBC+h+o0/1c+e",
            )
    fig.show()


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

   **Total running time of the script:** ( 0 minutes  2.664 seconds)


.. _sphx_glr_download_gallery_transformations_upward_derivative.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: upward_derivative.py <upward_derivative.py>`



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

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


.. only:: html

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

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