(DOCSP-6959) Adding information on viewing chart underlying data (#250)

* (DOCSP-6959) Adding 'View Underlying Data' page, screenshots

* Line breaks for docs review

* Moving work to 'Build Charts' page

* Most review changes, some still being discussed

* Changes based on feedback with two questions for external review

* Wording

* Moved to subpage

* Wording

* Consideration

* Formatting

* Changes based on feedback, incl. earlier feedback

* Copy

Author: zach-carr

source/build-charts.txt

@@ -19,15 +19,14 @@ charts, refer to the :ref:`Chart Types <chart-type-reference>` page.
 Create a Chart
 --------------
 
-To build a new chart:
-
 .. include:: /includes/steps/build-new-chart.rst
 
 .. class:: hidden
 
    .. toctree::
       :titlesonly:
 
+      /view-export-chart-data
       /encoding-channels
       /multi-series-charts
       /filter-documents

source/images/charts/editor-chart-data.png

@@ -0,0 +1,80 @@
+.. _view-export-chart-data:
+
+==========================
+View and Export Chart Data
+==========================
+
+.. default-domain:: mongodb
+
+.. contents:: On this page
+   :local:
+   :backlinks: none
+   :depth: 1
+   :class: singlecol
+
+While editing a chart in the Chart Builder, you can view underlying
+data from the :guilabel:`Ellipses (...)` dropdown menu. Access to
+underlying data is intended to help you build meaningful charts as well
+as export that data for use with third-party tools.
+
+.. figure:: /images/charts/editor-ellipse-menu.png
+   :figwidth: 60%
+   :alt: The ellipse menu is in the top-right corner of the charts editor.
+
+.. _view-source-documents:
+
+View Source Documents
+---------------------
+
+Once you have selected a :doc:`data source <data-sources>` for your
+chart, you can view 20 sample documents from that data source by
+clicking the :guilabel:`View Source Documents` menu option.
+
+.. note::
+   If you want to explore your data source beyond 20 sample documents,
+   you can use :compass:`Compass </>` or the 
+   :atlas:`Atlas Data Explorer </data-explorer/>`.
+
+The sample documents are intended for reference to help you build a
+chart. The documents do not reflect any groupings or projections
+applied to an existing chart (i.e. any :guilabel:`Encode` panel options
+in the Chart Builder). The documents are produced with a query on your
+data source that considers:
+
+- :ref:`Pipelines applied to the data source <data-sources-pipeline>`
+
+- :ref:`Sample mode <charts-sample-mode>` (if toggled on)
+
+- :ref:`Queries <query-bar>` or
+  :ref:`pipelines specified in the Chart Builder <charts-agg-pipeline>`
+  
+- Filters applied in the :ref:`Filter Tab <filter-tab>`
+
+.. _get-chart-data:
+
+Get Chart Data
+--------------
+
+After you have configured a valid chart, you can view the data
+displayed on the chart as a table. Each row in the table represents a
+data point. To view the chart data, click the :guilabel:`Get Chart Data`
+menu option.
+
+From the :guilabel:`Chart Data` dialog, you can download your
+chart data as a CSV or JSON file. This is useful for analyzing data
+with third-party tools.
+
+.. admonition:: Considerations
+   :class: important
+
+   Some Chart Builder configuration options (e.g. the :guilabel:`Limit
+   Results` option and the :guilabel:`Multiplier` field-level option)
+   apply only to the chart visualization and do not affect the
+   underlying data. The :guilabel:`Chart Data` table displays
+   underlying data, meaning some configuration options you see
+   reflected on a chart may not be applied to the table. Review your
+   data to verify its contents.
+
+.. figure:: /images/charts/editor-chart-data.png
+   :figwidth: 60%
+   :alt: Viewing chart data will display a table of the values used to create a chart. It also allows for downloading a CSV or JSON representation of that table.