Faceted Line Chart with Cumulative Sum

This chart creates one facet per natural disaster and shows the cumulative number of deaths for that category. Note the use of different predicates to filter based on both a list and a range.

Method syntax

import altair as alt
from vega_datasets import data

source = data.disasters()
columns_sorted = ['Drought', 'Epidemic', 'Earthquake', 'Flood']

alt.Chart(source).transform_filter(
    alt.FieldOneOfPredicate(field='Entity', oneOf=columns_sorted),
    alt.FieldRangePredicate(field='Year', range=[1900, 2000])
).transform_window(
    cumulative_deaths='sum(Deaths)', groupby=['Entity'] # Calculate cumulative sum of Deaths by Entity
).mark_line().encode(
    alt.X('Year:Q', title=None).axis(format='d'),
    alt.Y('cumulative_deaths:Q', title=None),
    alt.Color('Entity:N', legend=None)
).properties(
    width=300,
    height=150
).facet(
    facet=alt.Facet(
        'Entity:N',
        title=None,
        sort=columns_sorted,
        header=alt.Header(labelAnchor='start', labelFontStyle='italic')
    ),
    title=alt.Title(
        text=['Cumulative casualties by type of disaster', 'in the 20th century'],
        anchor='middle'
    ),
    columns=2
).resolve_axis(y='independent', x='independent')

Attribute syntax

import altair as alt
from vega_datasets import data

source = data.disasters()
columns_sorted = ['Drought', 'Epidemic', 'Earthquake', 'Flood']

alt.Chart(source).transform_filter(
    alt.FieldOneOfPredicate(field='Entity', oneOf=columns_sorted),
    alt.FieldRangePredicate(field='Year', range=[1900, 2000])
).transform_window(
    cumulative_deaths='sum(Deaths)', groupby=['Entity'] # Calculate cumulative sum of Deaths by Entity
).mark_line().encode(
    alt.X('Year:Q', title=None, axis=alt.Axis(format='d')),
    alt.Y('cumulative_deaths:Q', title=None),
    alt.Color('Entity:N', legend=None)
).properties(
    width=300,
    height=150
).facet(
    facet=alt.Facet(
        'Entity:N',
        title=None,
        sort=columns_sorted,
        header=alt.Header(labelAnchor='start', labelFontStyle='italic')
    ),
    title=alt.Title(
        text=['Cumulative casualties by type of disaster', 'in the 20th century'],
        anchor='middle'
    ),
    columns=2
).resolve_axis(y='independent', x='independent')