Sankey charts are an elegant and intuitive way to visualize flows and transformations of data. Named after the Scottish engineer and physicist who first proposed the concept, these charts have become a popular tool in data visualization for their ability to clearly depict the direction, magnitude, and composition of flows between different entities.

Understanding the Flow

A Sankey chart consists of nodes representing the sources, sinks, and intermediates of a flow, and links that connect these nodes, often with varying thicknesses to show the quantity or the amount of flow between the nodes. The chart’s strength lies in its ability to reveal patterns, connections, and distributions that might be obscured in tabular data, making it particularly useful in various fields such as economics, energy, materials processing, and web analytics.

Let’s explore some key aspects of creating and applying a Sankey chart in a practical workflow:

1. Data Preparation

The first step in creating a Sankey chart involves organizing your data into a suitable format. Most datasets that use Sankey charts include source (start point), target (end point), and the associated value (the flow or quantity moving between points). These datasets might come in the form of transaction logs, energy consumption data, or web page navigation statistics.

2. Choosing the Right Tool

Selecting the appropriate tool for creating a Sankey chart depends on your specific needs and familiarity with different software. Popular tools include:

• Tableau – Ideal for quick prototyping and visualization of large datasets with a user-friendly interface.
• D3.js – A powerful library for embedding interactive Sankey charts in web applications, great for web developers and those with some coding skills.
• Visio (Microsoft)** – Useful for integrating chart elements into documents or presentations effectively.

3. Designing the Chart

Customize the appearance and functionality of your Sankey chart by:

• Layout – Arrange the nodes to optimize the flow visualization and readability.
• Colors – Use distinct colors for different flows or categories to enhance understanding.
• Thickness – Adjust the width of the links to depict the volume of the flow accurately.
• Labels and Legends – Clearly indicate what each node and link represents, aiding in the interpretation of the chart.

4. Interpretation and Analysis

Once the visual representation is complete, use the chart to:

• Identify Hotspots – Look for areas with significant flow that might indicate important processes or relationships.
• Detect Trends – Analyze how the flows have changed over time if your data spans multiple periods.
• Highlight Anomalies – Unusual patterns can point to errors or exceptional events that require further investigation.

5. Application Cases

Sankey charts find applications in a wide range of fields:

• Energy Systems – Displaying energy flow from sources, through intermediates to final use, useful for energy audits or sustainability studies.
• Economic Flows – Analyzing trade patterns or movement of capital between different economies.
• Web Analytics – Mapping user journey across a website, understanding which pages and paths attract the most traffic.

6. Best Practices

• Simplicity – Avoid cluttering the chart with too much detail that might obscure the main message.
• Consistency – Use consistent design elements (like colors and labels) throughout the chart to aid readability.
• Accessibility – Ensure the chart can be easily understood by your target audience, including those who might have color blindness.

Conclusion

Sankey charts are a powerful tool for visualizing complex flows and transformations in data. By carefully preparing your data, utilizing the right tools, and leveraging design principles, you can create insightful and impactful charts that enhance understanding and decision-making across various industries. Whether you’re analyzing energy usage patterns, web user journeys, or trade dynamics, a well-designed Sankey chart can provide invaluable insights into the underlying structure of the data.

SankeyMaster

SankeyMaster is your go-to tool for creating complex Sankey charts . Easily enter data and create Sankey charts that accurately reveal intricate data relationships.