.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "gallery/XY/NCL_xy_13.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_13.py>`
        to download the full example code.

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

.. _sphx_glr_gallery_XY_NCL_xy_13.py:


NCL_xy_13.py
===============
This script illustrates the following concepts:
    - Adding error bars on an XY plot

See following URLs to see the reproduced NCL plot & script:
    - Original NCL script: https://www.ncl.ucar.edu/Applications/Scripts/xy_13.ncl
    - Original NCL plots: https://www.ncl.ucar.edu/Applications/Images/xy_13_lg.png

.. GENERATED FROM PYTHON SOURCE LINES 13-14

Import packages:

.. GENERATED FROM PYTHON SOURCE LINES 14-23

.. code-block:: Python


    import numpy as np
    import xarray as xr
    import matplotlib.pyplot as plt
    from matplotlib import collections as mc

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








.. GENERATED FROM PYTHON SOURCE LINES 24-25

Read in data:

.. GENERATED FROM PYTHON SOURCE LINES 25-50

.. 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/uv300.nc"))

    # Extract data
    V = ds.isel(time=0, lon=30, drop=True).V

    # Create arrays to represent the magnitude of error above and below the line
    # This data is arbitrary and you should replace these arrays with the actual
    # error for your dataset
    err_above = V.data + 1.5
    err_below = V.data - 1
    x = range(0, 64)  # the x values used to plot the data and error bars

    # Make a tuple to represent the bottom and top points of the error bar
    err_below = tuple(zip(x, err_below))
    err_above = tuple(zip(x, err_above))

    # Make a tuple containing those points to describe the line segment
    segments = tuple(zip(err_below, err_above))

    # Create a line collection so we can plot all of the segments with one call
    bars = mc.LineCollection(segments, colors='black', linewidths=0.5)








.. GENERATED FROM PYTHON SOURCE LINES 51-52

Plot:

.. GENERATED FROM PYTHON SOURCE LINES 52-80

.. code-block:: Python

    plt.figure(figsize=(8, 8))
    ax = plt.axes()

    # Plots the data with markers
    plt.plot(x, V.data, color='black', linewidth=0.5, marker='.')

    # Plot the error bars
    ax.add_collection(bars)

    # Use geocat.viz.util convenience function to set axes parameters
    gv.set_axes_limits_and_ticks(
        ax,
        xlim=(0, 70),
        ylim=(-9, 9),
        xticks=np.arange(0, 71, 10),
        yticks=np.arange(-9, 10, 3),
        yticklabels=np.arange(-9.0, 10.0, 3.0),
    )

    # 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=3, labelsize=14)

    # Use geocat.viz.util convenience function to set titles and labels
    gv.set_titles_and_labels(
        ax, maintitle="Example of error bars", ylabel=V.long_name + " " + V.units
    )

    plt.show()



.. image-sg:: /gallery/XY/images/sphx_glr_NCL_xy_13_001.png
   :alt: Example of error bars
   :srcset: /gallery/XY/images/sphx_glr_NCL_xy_13_001.png
   :class: sphx-glr-single-img






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

   **Total running time of the script:** (0 minutes 0.095 seconds)


.. _sphx_glr_download_gallery_XY_NCL_xy_13.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_13.ipynb <NCL_xy_13.ipynb>`

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

      :download:`Download Python source code: NCL_xy_13.py <NCL_xy_13.py>`

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

      :download:`Download zipped: NCL_xy_13.zip <NCL_xy_13.zip>`


.. only:: html

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

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