Stream Graphs: Structure, Scale, and Story

Trends over time are often shown with line or area charts. But when composition matters as much as magnitude, Stream Graphs provide clarity.

A Stream Graph is a stacked area chart with flowing layers around a central axis. It shows how categories change over time, highlighting both relative size and variation.

When to Use Stream Graphs

• Tracking category contributions over time (e.g., lead sources, support volumes)

• Identifying seasonal or cyclical patterns across dimensions

• Visualizing data where relative and absolute trends both matter

Use Case: Lead Volume by Marketing Channel
We compared five marketing channels over time. The Stream Graph revealed:

• How total lead volume evolved

• When specific channels, such as Social Media, surged

• Not just values, but shifts in rhythm and contribution

Comparison: Stream vs. Line Chart

• Line charts overlap, flattening the view

• No visibility into stacked dominance or share shifts

• Harder to interpret composition changes

Why Stream Graphs Work

• Visual hierarchy highlights dominant contributors

• Layered movement shows transitions over time

• Combines composition and trend in one frame