.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "gallery/XY/NCL_xy_16.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

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

        :ref:`Go to the end <sphx_glr_download_gallery_XY_NCL_xy_16.py>`
        to download the full example code.

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

.. _sphx_glr_gallery_XY_NCL_xy_16.py:


NCL_xy_16.py
===============
This script illustrates the following concepts:
   - Drawing a legend inside an XY plot
   - Drawing an X reference line in an XY plot
   - Reversing the Y axis
   - Using log scaling and explicit labeling
   - Changing the labels in a legend
   - Creating a vertical profile plot

See following URLs to see the reproduced NCL plot & script:
    - Original NCL script: https://www.ncl.ucar.edu/Applications/Scripts/xy_16.ncl
    - Original NCL plots: https://www.ncl.ucar.edu/Applications/Images/xy_16_1_lg.png and https://www.ncl.ucar.edu/Applications/Images/xy_16_2_lg.png

.. GENERATED FROM PYTHON SOURCE LINES 18-19

Import packages:

.. GENERATED FROM PYTHON SOURCE LINES 19-29

.. code-block:: Python


    import numpy as np
    import xarray as xr
    import matplotlib.pyplot as plt
    from matplotlib.ticker import ScalarFormatter, NullFormatter
    import matplotlib.ticker as tic

    import geocat.datafiles as gdf
    import geocat.viz as gv








.. GENERATED FROM PYTHON SOURCE LINES 30-31

Read in data:

.. GENERATED FROM PYTHON SOURCE LINES 31-42

.. code-block:: Python


    # Open a netCDF data file using xarray default engine and load the data into xarrays
    ds = xr.open_dataset(gdf.get("netcdf_files/atmos.nc"), decode_times=False)
    U = ds.U.isel(time=0, lon=0, drop=True)

    # Extract slices of the data at different latitudes using the index of the desired value
    U20 = U.isel(lat=39, drop=True)
    U30 = U.isel(lat=42, drop=True)
    U40 = U.isel(lat=46, drop=True)
    U50 = U.isel(lat=49, drop=True)








.. GENERATED FROM PYTHON SOURCE LINES 43-44

Plot with linear y axis:

.. GENERATED FROM PYTHON SOURCE LINES 44-94

.. code-block:: Python


    # Generate figure (set its size (width, height) in inches) and axes
    plt.figure(figsize=(8, 8))
    ax = plt.axes()

    # Use geocat.viz.util convenience function to add minor and major tick lines
    gv.add_major_minor_ticks(ax, x_minor_per_major=5, y_minor_per_major=4, labelsize=14)

    # Use geocat.viz.util convenience function to set axes parameters
    gv.set_axes_limits_and_ticks(
        ax,
        xlim=(-20, 40),
        ylim=(1000, 0),
        xticks=np.arange(-20, 60, 10),
        yticks=np.arange(0, 1200, 200),
    )

    # Use geocat.viz.util convenience function to set titles and labels
    gv.set_titles_and_labels(
        ax, maintitle='Profile Plot', xlabel=U.long_name, ylabel=U['lev'].long_name
    )

    # Add reference line x=0
    ax.axvline(x=0, color='black', linewidth=0.5)

    # Plot data
    plt.plot(
        U20.data, U20.lev, color='black', linestyle='solid', label='20N', linewidth=0.5
    )
    plt.plot(U30.data, U30.lev, color='black', dashes=[15, 5], label='30N', linewidth=0.5)
    plt.plot(U40.data, U40.lev, color='black', dashes=[4, 5], label='40N', linewidth=0.5)
    plt.plot(
        U50.data, U50.lev, color='black', dashes=[15, 5, 5, 5], label='50N', linewidth=0.5
    )

    # Add legend
    handles, labels = ax.get_legend_handles_labels()

    plt.legend(
        handles,
        labels,
        loc='center right',
        frameon=False,
        fontsize=14,
        labelspacing=1,
        reverse=True,
    )

    plt.show()




.. image-sg:: /gallery/XY/images/sphx_glr_NCL_xy_16_001.png
   :alt: Profile Plot
   :srcset: /gallery/XY/images/sphx_glr_NCL_xy_16_001.png
   :class: sphx-glr-single-img





.. GENERATED FROM PYTHON SOURCE LINES 95-96

Plot with logarithmic y axis:

.. GENERATED FROM PYTHON SOURCE LINES 96-171

.. code-block:: Python


    # Generate figure (set its size (width, height) in inches) and axes
    plt.figure(figsize=(8, 8))
    ax = plt.axes()

    # Note: Currently geocat-viz does not have a utility function for formatting
    # major and minor ticks on logarithmic axes.
    plt.yscale('log')
    ax.yaxis.set_major_formatter(ScalarFormatter())
    ax.yaxis.set_minor_formatter(NullFormatter())
    ax.tick_params(labelsize=14)
    ax.minorticks_on()
    ax.xaxis.set_minor_locator(tic.AutoMinorLocator(n=5))
    # Specify no minor ticks on log y axis
    ax.yaxis.set_minor_locator(tic.LogLocator())
    # Length and width are in points and may need to change depending on figure size
    ax.tick_params(
        "both",
        length=8,
        width=0.9,
        which="major",
        bottom=True,
        top=True,
        left=True,
        right=True,
    )
    ax.tick_params(
        "both",
        length=4,
        width=0.4,
        which="minor",
        bottom=True,
        top=True,
        left=True,
        right=True,
    )

    # Use geocat.viz.util convenience function to set axes parameters
    pressure_lvls = [1, 5, 10, 30, 50, 100, 200, 300, 400, 500, 700, 1000]
    gv.set_axes_limits_and_ticks(
        ax,
        xlim=(-20, 40),
        ylim=(1000, 4),
        xticks=np.arange(-20, 60, 10),
        yticks=pressure_lvls,
    )

    # Use geocat.viz.util convenience function to set titles and labels
    gv.set_titles_and_labels(ax, maintitle='Profile Plot', xlabel=U.long_name)

    # Plot data
    plt.plot(
        U20.data, U20.lev, color='black', linestyle='solid', label='20N', linewidth=0.5
    )
    plt.plot(U30.data, U30.lev, color='black', dashes=[15, 5], label='30N', linewidth=0.5)
    plt.plot(U40.data, U40.lev, color='black', dashes=[4, 5], label='40N', linewidth=0.5)
    plt.plot(
        U50.data, U50.lev, color='black', dashes=[15, 5, 5, 5], label='50N', linewidth=0.5
    )

    # Add legend
    handles, labels = ax.get_legend_handles_labels()
    # Default order is the order in which the data was plotted

    plt.legend(
        handles,
        labels,
        loc='center right',
        frameon=False,
        fontsize=14,
        labelspacing=1,
        reverse=True,
    )

    plt.show()



.. image-sg:: /gallery/XY/images/sphx_glr_NCL_xy_16_002.png
   :alt: Profile Plot
   :srcset: /gallery/XY/images/sphx_glr_NCL_xy_16_002.png
   :class: sphx-glr-single-img






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

   **Total running time of the script:** (0 minutes 0.263 seconds)


.. _sphx_glr_download_gallery_XY_NCL_xy_16.py:

.. only:: html

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

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

      :download:`Download Jupyter notebook: NCL_xy_16.ipynb <NCL_xy_16.ipynb>`

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

      :download:`Download Python source code: NCL_xy_16.py <NCL_xy_16.py>`

    .. container:: sphx-glr-download sphx-glr-download-zip

      :download:`Download zipped: NCL_xy_16.zip <NCL_xy_16.zip>`


.. only:: html

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

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