.. _graphics-TEC:


Ionosphere space weather
========================

This space weather example plots a filled contour of rotated pole point data with a blue marble underlay.
The plot shows aggregated vertical electron content in the ionosphere.

The plot exhibits an interesting outline effect due to excluding data values below a certain threshold.



.. plot:: /net/home/h06/ecamp/nounpack_iris/docs/iris/example_code/graphics/TEC.py

::

    """
    Ionosphere space weather
    ========================
    
    This space weather example plots a filled contour of rotated pole point data with a blue marble underlay.
    The plot shows aggregated vertical electron content in the ionosphere.
    
    The plot exhibits an interesting outline effect due to excluding data values below a certain threshold.
    
    """
    
    import matplotlib.pyplot as plt
    import numpy as np
    
    import iris
    import iris.plot as iplt
    import iris.quickplot as qplt
    
    
    def total_electron_content_filter(cube, field, filename):
        # Filter out all cubes that don't have a matching 'long_name' attribute.
        if hasattr(field, 'long_name') and field.long_name != 'total electron content':
            raise iris.exceptions.IgnoreCubeException()
    
    
    def main():
        # Load the "total electron content" cube.
        filename = iris.sample_data_path('space_weather.nc')
        cube = iris.load_strict(filename, 'total electron content')
    
        # Explicitly mask negative electron content.
        cube.data = np.ma.masked_less(cube.data, 0)
    
        # Currently require to remove the multi-dimensional
        # latitude and longitude coordinates for Iris plotting.
        cube.remove_coord('latitude')
        cube.remove_coord('longitude')
    
        # Plot the cube using one hundred colour levels.
        qplt.contourf(cube, 100)
        plt.title('Total Electron Content')
        plt.xlabel('longitude / degrees')
        plt.ylabel('latitude / degrees')
        iplt.gcm().bluemarble(zorder=-1)
        iplt.gcm().drawcoastlines()
        plt.show()
    
    
    if __name__ == '__main__':
        main()