Sankey diagrams are a powerful visualization tool used to depict the flow or movement of transferring items between different values, nodes, or processes. These charts are named after Mark P. Sankey, an engineer who used flow diagrams to illustrate steam flows through power stations in the late 19th century. Since then, Sankey diagrams have been widely adopted across various fields, including energy auditing, data analysis, financial models, and environmental science, to illustrate data flows, resource transfers, and economic systems.

Understanding Sankey Charts

At their core, Sankey diagrams are graphical representations of flows. They are structured as a network of links that can represent physical or abstract flows such as water, energy, materials, money, data, and people. Each link is typically drawn with a width proportional to the flow quantity or ‘strength.’ The directionality of the flow is shown by the arrows, and the position of nodes represents different stages or points in the flow process.

Creation of Sankey Charts

Creating a Sankey chart from scratch can be a complex process, but fortunately, numerous software tools and programming languages can help streamline the creation process. Here are some steps and methods to consider:

1. Data Preparation: Collect and organize your data in a format that represents the starting points, the flow between points, and the final destinations. The data should be in a tabular format where the columns represent nodes and rows represent flows.

2. Software Tools: Many software tools include free and paid options to create Sankey diagrams. Popular choices include Adobe Illustrator, Lucidchart, and Draw.io. For those with programming skills, Python is a powerful tool, thanks to libraries like Plotly, Bokeh, and Altair, which are well-suited for data visualization.

3. Coding the Chart: For programmers, coding a Sankey diagram can be both rewarding and complex. The basic steps involve setting up the data, deciding on the scale of the flow relative to link width, and plotting the nodes and links. Libraries like Plotly offer pre-built functions to simplify the process.

Applications of Sankey Charts

Sankey diagrams are versatile and can be applied across a wide range of domains. Here are some common applications:

• Energy Industry: Sankey diagrams are commonly used to represent the energy input and output in systems, such as in power plants or homes, showing energy transfers from source to final destination.

• Financial Models: In the financial sector, Sankey diagrams can illustrate the movement of investment funds through various stages, from initial investment to eventual returns, highlighting risks and potential.

• Ecology and Environment: These diagrams are indispensable in ecological studies, showing how energy is transferred between trophic levels or how water flows through ecosystems.

• Data Analytics: Sankey diagrams are invaluable in data analytics for visualizing data flow in complex systems, like the flow of data through databases or the information flow in a social media platform.

• Healthcare and Medicine: In healthcare, they are used to visualize resource allocation and patient flow through various stages of care processes, aiding in resource allocation and process optimization.

Conclusion

Sankey diagrams are a remarkably effective tool for visualizing flow data, making complex interactions and processes understandable at a glance. Whether in the energy sector, finance, ecology, or data analytics, these diagrams are a valuable asset for data visualization professionals. With the right software and programming tools, creating a Sankey diagram has become accessible, enhancing our ability to understand and communicate the intricate relationships between data flows. As data science continues to evolve, so too will the prominence and diversity of Sankey diagrams in the toolbox of data visualization techniques.

SankeyMaster

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