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

.. _gallery_layered_heatmap_text:


Layering text over a heatmap
----------------------------

An example of a layered chart of text over a heatmap using the cars dataset.


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

    
    import altair as alt
    from altair.expr import datum
    from vega_datasets import data

    cars = data.cars.url

    heatmap = alt.Chart(cars).mark_rect().encode(
        alt.X('Cylinders:O', scale=alt.Scale(paddingInner=0)),
        alt.Y('Origin:O', scale=alt.Scale(paddingInner=0)),
        color='count()'
    )

    text = alt.Chart(cars).mark_text(baseline='middle').encode(
        x='Cylinders:O',
        y='Origin:O',
        text='count()',
        color=alt.condition(datum['count_*'] > 100,
                            alt.value('black'),
                            alt.value('white'))
    )

    heatmap + text


.. toctree::
   :hidden: