.. This document is auto-generated by the altair-gallery extension. Do not modify directly.

.. _gallery_interval_selection:


Interval Selection Example
==========================

This is an example of creating a stacked chart for which the domain of the
top chart can be selected by interacting with the bottom chart.


.. altair-plot::
    :code-below:

    
    import altair as alt
    from vega_datasets import data

    source = data.sp500.url

    brush = alt.selection(type='interval', encodings=['x'])

    base = alt.Chart(source).mark_area().encode(
        x = 'date:T',
        y = 'price:Q'
    ).properties(
        width=600,
        height=200
    )

    upper = base.encode(
        alt.X('date:T', scale=alt.Scale(domain=brush))
    )

    lower = base.properties(
        height=60
    ).add_selection(brush)

    upper & lower


.. toctree::
   :hidden: