.. _latitude_bin:

Latitude Binning
^^^^^^^^^^^^^^^^

This example shows how to plot ozone at 32.5 km for weekly means grouped into
5 degree latitude bins.

.. code-block:: python

    import os
    import xarray as xr
    import numpy as np
    import matplotlib.pyplot as plt

    # define a function to do the latitude binning with xarray's map function
    def latitude_bin(ds, lat_res, lat_min, lat_max):
        lat_bins = np.arange(lat_min, lat_max, lat_res)
        data_groups = ds.groupby_bins(ds.latitude, lat_bins, labels=lat_bins[1::] - lat_res / 2)
        data_mean = data_groups.mean(dim='time')
        return data_mean

    # load the 2012 data and set time as the dimension
    v7_folder = r'path\to\v7_data'
    data = xr.open_mfdataset(os.path.join(v7_folder, '*.nc'))
    data = data.swap_dims({'profile_id': 'time'})
    data = data.sel(time='2012')

    # resample for weekly means, loffset fixes the alignment of ticks when plotting
    data_resample = data.resample(time='7D', loffset='84H')
    data_bin = data_resample.map(latitude_bin, args=(5, -90, 91))

    data_bin.ozone_concentration.sel(altitude=32.5).plot(x='time', figsize=[8, 5])


.. image:: ../images/o3_lat_bins.png
   :align: center