.. _gwpy-example-segments-open-data:

.. sectionauthor:: Duncan Macleod <duncan.macleod@ligo.org>

.. currentmodule:: gwpy.segments

Plotting observing segments for O1
##################################

The data from the full
`Observing Run 1 (O1) <https://www.gw-openscience.org/O1/>`__
have been released by |GWOSC|_.

This example demonstrates how to download segment information into a
:class:`~gwpy.segments.DataQualityFlag`, and then plot them.

All we need to do is import the `DataQualityFlag` object, and then call
the :meth:`DataQualityFlag.fetch_open_data` method to query for, and download
the segments for all of O1:


.. plot::
   :context: reset
   :nofigs:
   :include-source:

   from gwpy.segments import DataQualityFlag
   h1segs = DataQualityFlag.fetch_open_data('H1_DATA', 'Sep 12 2015',
                                            'Jan 19 2016')

We can then generate a plot of the times when LIGO-Hanford was operating:


.. plot::
   :context:
   :include-source:

   plot = h1segs.plot(color='gwpy:ligo-hanford')
   plot.show()

That's a lot of segments. We can pare-down the list a little to display
only the segments from the first month of the run:


.. plot::
   :context: close-figs
   :nofigs:
   :include-source:

   h1month1 = DataQualityFlag.fetch_open_data('H1_DATA', 'Sep 12 2015',
                                              'Oct 12 2015')

We can also download the LIGO-Livingston segments from the same period
and display them alongside, as well as those segments during which both
interferometers were operating at the same time
(see :ref:`gwpy-segments-intersection` for more details on this use of the
``&`` operator):


.. plot::
   :context:
   :include-source:

   l1month1 = DataQualityFlag.fetch_open_data('L1_DATA', 'Sep 12 2015',
                                              'Oct 12 2015')
   bothon = h1month1 & l1month1
   plot = h1month1.plot()
   ax = plot.gca()
   ax.plot(l1month1)
   ax.plot(bothon, label='Both')
   plot.show()