Re-plot saved data
******************

Problem
=======

Re-create a plot (or table, or other live "subscription") on saved data.

Approach
========

In the example :doc:`/examples/simple-scan`, we set up a ``LiveTable`` and
``LivePlot``. We subscribed them to the stream of data coming from the
RunEngine, and they updated live during the scan.

Now, we will make a ``LivePlot`` again, using the same code,
but we will stream *saved* data from the databroker. The table and plot
don't "know" where the data is coming from; they work just the same on
live data or saved data. The two can even be mixed on the same plot.

Example Solution
================

These may already be imported in your configuration. If not, import them.

.. code-block:: python

    from databroker import db
    from bluesky.callbacks import LiveTable


Search for the run in question.

.. note::

    There are many ways to search for data. The simplest is by recency:
    ``db[-1]`` means "get me the last run". A more reliable method is to
    use the run's unique ID. See
    `this section <http://nsls-ii.github.io/databroker/searching.html>`_
    of the databroker documentation for more.

.. code-block:: python

    h = db[-1]

Define a ``LivePlot``, as we did when we collected the data in
:doc:`/examples/simple-scan`.

.. code-block:: python

    p = LivePlot('det', 'motor')

Now use the ``process`` method of the databroker to process all the data
from ``h`` with ``LivePlot``.

.. code-block:: python

    db.process(h, p)

We obtain the exact same plot:

.. image:: ../_static/simple-scan.png

To plot more data on the same axes, reuse ``p``. To get fresh axes, define
``p`` again.

For example, to add more saved data:

.. code-block:: python

    h  = db[-2]  # the second-most-recent run
    db.process(h, p)

To now add *live* data from a new scan, include ``p`` as a subscription.
(For context, refer to :doc:`/examples/simple-scan`.)

.. code-block:: python

    subs = [LiveTable(['motor', 'det']), p]
    RE(scan([det], motor, -5, 5, 10), p)