:orphan:
:html_theme.sidebar_secondary.remove:
.. This document is auto-generated by the altair-gallery extension. Do not modify directly.
.. _gallery_choropleth:
Choropleth Map
==============
A choropleth map of unemployment rate per county in the US
.. altair-plot::
:remove-code:
import altair as alt
from vega_datasets import data
counties = alt.topo_feature(data.us_10m.url, 'counties')
source = data.unemployment.url
alt.Chart(counties).mark_geoshape().encode(
color='rate:Q'
).transform_lookup(
lookup='id',
from_=alt.LookupData(source, 'id', ['rate'])
).project(
type='albersUsa'
).properties(
width=500,
height=300
)
# 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
counties = alt.topo_feature(data.us_10m.url, 'counties')
source = data.unemployment.url
alt.Chart(counties).mark_geoshape().encode(
color='rate:Q'
).transform_lookup(
lookup='id',
from_=alt.LookupData(source, 'id', ['rate'])
).project(
type='albersUsa'
).properties(
width=500,
height=300
)
.. tab-item:: Attribute syntax
:sync: attribute
.. code:: python
import altair as alt
from vega_datasets import data
counties = alt.topo_feature(data.us_10m.url, 'counties')
source = data.unemployment.url
alt.Chart(counties).mark_geoshape().encode(
color='rate:Q'
).transform_lookup(
lookup='id',
from_=alt.LookupData(source, 'id', ['rate'])
).project(
type='albersUsa'
).properties(
width=500,
height=300
)
# No channel encoding options are specified in this chart
# so the code is the same as for the method-based syntax.