:orphan:
:html_theme.sidebar_secondary.remove:

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

.. _gallery_one_dot_per_zipcode:


One Dot Per Zipcode
-----------------------
This example shows a geographical plot with one dot per zipcode.


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


    import altair as alt
    from vega_datasets import data

    # Since the data is more than 5,000 rows we'll import it from a URL
    source = data.zipcodes.url

    alt.Chart(source).transform_calculate(
        "leading digit", alt.expr.substring(alt.datum.zip_code, 0, 1)
    ).mark_circle(size=3).encode(
        longitude='longitude:Q',
        latitude='latitude:Q',
        color='leading digit:N',
        tooltip='zip_code:N'
    ).project(
        type='albersUsa'
    ).properties(
        width=650,
        height=400
    )
    # 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 vega_datasets import data

            # Since the data is more than 5,000 rows we'll import it from a URL
            source = data.zipcodes.url

            alt.Chart(source).transform_calculate(
                "leading digit", alt.expr.substring(alt.datum.zip_code, 0, 1)
            ).mark_circle(size=3).encode(
                longitude='longitude:Q',
                latitude='latitude:Q',
                color='leading digit:N',
                tooltip='zip_code:N'
            ).project(
                type='albersUsa'
            ).properties(
                width=650,
                height=400
            )


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

        .. code:: python


            import altair as alt
            from vega_datasets import data

            # Since the data is more than 5,000 rows we'll import it from a URL
            source = data.zipcodes.url

            alt.Chart(source).transform_calculate(
                "leading digit", alt.expr.substring(alt.datum.zip_code, 0, 1)
            ).mark_circle(size=3).encode(
                longitude='longitude:Q',
                latitude='latitude:Q',
                color='leading digit:N',
                tooltip='zip_code:N'
            ).project(
                type='albersUsa'
            ).properties(
                width=650,
                height=400
            )
            # No channel encoding options are specified in this chart
            # so the code is the same as for the method-based syntax.