Sankey charts are a type of flow diagram that visually represents the movement of data or material through a system. They are named after their inventor, Captain Matthew Henry Phibbs Sankey, who developed them in the 1860s while working for the steam engine manufacturer, Isambard Kingdom Brunel. Since then, Sankey charts have evolved and gained popularity as a powerful tool for mapping complex flows and transforming data into insights. In this article, we’ll explore the creation and applications of Sankey charts to help you unleash their visual power.

Creating Sankey Charts

Creating a Sankey chart involves several steps, including data preparation, layout design, and visual customization. Here’s a brief overview of the process:

1. Data Preparation: To create a Sankey chart, you need structured data that includes three main components:

   • Source – Where the flow originates.
   • Target – Where the flow is directed.
   • Value – The quantity or amount of the flow.

   Ensure your data is in a format that can be easily visualized, such as a CSV or Excel file. It’s helpful to have a unique identifier for each source and target node or label to allow for clear organization and presentation.

2. Layout Design: There are several ways to arrange your Sankey chart, depending on the story you want to tell. Popular designs include vertical, horizontal, and radial layouts. Consider the following:

   • Flow Orientation: Decide if you want the arrow lines of the flows to move from left to right or top to bottom.
   • Node Spacing: Ensure nodes are appropriately spaced to maintain clarity and readability.
   • Color Scheme: Use a consistent and meaningful color scheme to differentiate between sources, targets, and flow values.

3. Visual Customization: Customize your chart to enhance readability and aesthetics. This can include adjusting:

   • Width of Links: Based on the value of the flow, wider links represent larger flows.
   • Arrowhead Styles: Experiment with different arrowhead types to improve visual impact.
   • Interactive Elements: If using software that supports interactivity, like a web-based Sankey chart builder, add tooltips or hover effects to show additional data when users interact with the chart.

Use Software and Tools: Consider using specialized software or online tools like Microsoft Power BI, Tableau, Sankey diagram generators, or libraries like Plotly for Python and JavaScript, to create your Sankey charts. These tools significantly simplify the creation process and offer customization options to tailor your charts to your specific needs.

Applications of Sankey Charts

Sankey charts excel in visualizing a wide range of flow-related data stories. Here are several applications across various fields:

1. Energy Systems: In the energy sector, Sankey diagrams are invaluable for illustrating energy production, usage, and loss across different stages or systems. They help identify energy inefficiencies and guide optimization efforts.

2. Economic Flows: Economists use Sankey charts to track the movement of goods, services, and capital flows between regions, industries, or market sectors. This provides insights into trade relationships, value distribution, and economic dependency.

3. Material Flows: In manufacturing and sustainability contexts, Sankey diagrams depict the flow of materials through processes and systems, emphasizing waste and recovery potentials, critical for environmental impact assessments.

4. Healthcare: Healthcare analysts use Sankey charts to map patient flows within hospitals, clinics, or treatment pathways, highlighting bottlenecks and optimizing patient care processes.

5. Internet Traffic: IT professionals employ Sankey diagrams to visualize web traffic flows, network usage patterns, and server interactions, aiding in system optimization and resource management.

Conclusion

Sankey charts offer a compelling way to visualize and gain insights from complex flow data. Their creation involves data preparation, thoughtful layout design, and customization. Thanks to software advancement and user-friendly tools, they are increasingly adopted in various fields. By mastering the creation and applications of Sankey charts, you can effectively communicate intricate data stories and drive evidence-based decision-making.

SankeyMaster

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