"""
Gapminder Bubble Plot
=====================
This example shows how to make a bubble plot showing the correlation between
health and income for 187 countries in the world (modified from an example
in Lisa Charlotte Rost's blog post `'One Chart, Twelve Charting Libraries' <http://lisacharlotterost.github.io/2016/05/17/one-chart-code/>`_.
"""
# category: case studies
import altair as alt
from vega_datasets import data

source = data.gapminder_health_income.url

alt.Chart(source).mark_circle().encode(
    alt.X('income:Q', scale=alt.Scale(type='log')),
    alt.Y('health:Q', scale=alt.Scale(zero=False)),
    size='population:Q'
)