
:orphan:
:html_theme.sidebar_secondary.remove:

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

.. _gallery_trail_marker:


Line Chart with Varying Size
----------------------------
This is example of using the ``trail`` marker to vary the size of a line.


.. altair-plot::
    :remove-code:
    


    import altair as alt
    from altair.datasets import data

    source = data.wheat()

    alt.Chart(source).mark_trail().encode(
        x='year:T',
        y='wheat:Q',
        size='wheat:Q'
    )
    # No channel encoding options are specified in this chart
    # so the code is the same as for the method-based syntax.


.. tab-set::

    .. tab-item:: Method syntax
        :sync: method

        .. code:: python


            import altair as alt
            from altair.datasets import data

            source = data.wheat()

            alt.Chart(source).mark_trail().encode(
                x='year:T',
                y='wheat:Q',
                size='wheat:Q'
            )


    .. tab-item:: Attribute syntax
        :sync: attribute

        .. code:: python


            import altair as alt
            from altair.datasets import data

            source = data.wheat()

            alt.Chart(source).mark_trail().encode(
                x='year:T',
                y='wheat:Q',
                size='wheat:Q'
            )
            # No channel encoding options are specified in this chart
            # so the code is the same as for the method-based syntax.
