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

.. only:: html

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

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

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

.. _sphx_glr_source_auto_examples_utils_plot_change_units.py:


Changing units in dataset
-------------------------

This is an example of how to change
units in the xarray dataset.

.. GENERATED FROM PYTHON SOURCE LINES 9-66




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

 .. code-block:: none

    Variables in read data
    first_cbh: mean=677.3226928710938 units=m
    second_cbh: mean=872.345703125 units=m
    alt: mean=318.0 units=m

    Variables with one changed to km
    first_cbh: mean=0.6773227453231812 units=km
    second_cbh: mean=872.345703125 units=m
    alt: mean=318.0 units=m

    Variables with both changed to km
    first_cbh: mean=0.6773227453231812 units=km
    second_cbh: mean=0.8723457455635071 units=km
    alt: mean=0.31800001859664917 units=km

    Variables changed back to m by looping over all variables in dataset
    Orginal dataset is same as retured dataset: True
    first_cbh: mean=677.3226928710938 units=m
    second_cbh: mean=872.345703125 units=m
    alt: mean=318.0000305175781 units=m

    Variables and coordinate variable values changed to km
    Orginal dataset is same as retured dataset: False
    first_cbh: mean=0.6773227453231812 units=km
    second_cbh: mean=0.8723457455635071 units=km
    alt: mean=0.31800004839897156 units=km
    range: mean=3.7800002098083496 units=km







|

.. code-block:: Python


    from arm_test_data import DATASETS
    import numpy as np

    import act


    def print_summary(ds, variables):
        for var_name in variables:
            print(
                f'{var_name}: mean={np.nanmean(ds[var_name].values)} '
                f"units={ds[var_name].attrs['units']}"
            )
        print()


    variables = ['first_cbh', 'second_cbh', 'alt']

    # Read in some example data
    filename_ceil = DATASETS.fetch('sgpceilC1.b1.20190101.000000.nc')
    ds = act.io.arm.read_arm_netcdf(filename_ceil)

    # Print the variable name, mean of values and units
    print('Variables in read data')
    print_summary(ds, variables)

    # Change units of one varible from m to km
    ds.utils.change_units(variables='first_cbh', desired_unit='km')
    print('Variables with one changed to km')
    print_summary(ds, variables)

    # Change units of more than one varible from to km
    ds.utils.change_units(variables=variables, desired_unit='km')
    print('Variables with both changed to km')
    print_summary(ds, variables)

    # Can change all data variables in the dataset that are units of length by not providing
    # a list of variables. Here we are changing back to orginal meters.
    # Also, because it needs to loop over all variables and try to convert, will take
    # longer if we keep the QC variables. Faseter if we exclude them.
    # The method will return a dataset. In this case the dataset returned is the same
    # dataset.
    skip_variables = [ii for ii in ds.data_vars if ii.startswith('qc_')]
    new_ds = ds.utils.change_units(variables=None, desired_unit='m', skip_variables=skip_variables)
    print('Variables changed back to m by looping over all variables in dataset')
    print('Orginal dataset is same as retured dataset:', ds is new_ds)
    print_summary(new_ds, variables)

    # For coordinate variables need to explicitly give coordinage variable name and use
    # the returned dataset. The xarray method used to change values on coordinate
    # values requries returning a new updated dataet.
    var_name = 'range'
    variables.append(var_name)
    new_ds = ds.utils.change_units(variables=variables, desired_unit='km')
    print('Variables and coordinate variable values changed to km')
    print('Orginal dataset is same as retured dataset:', ds is new_ds)
    print_summary(new_ds, variables)


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

   **Total running time of the script:** (0 minutes 3.722 seconds)


.. _sphx_glr_download_source_auto_examples_utils_plot_change_units.py:

.. only:: html

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

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

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

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

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

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

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


.. only:: html

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

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