Flowcharts with a Flow: Unveiling the Magic of Sankey Charts

In the realm of data visualization, few tools are as versatile and visually captivating as the Sankey chart. This sophisticated data visualization tool allows users to map the flow from one set of values to another. Unlike traditional pie charts and bar graphs, which provide a snapshot of data at a single point, Sankey diagrams offer a dynamic representation of data flow, making it easier for audiences to grasp the magnitude and direction of changes over time. This article aims to delve into the intricacies of Sankey chart creation and explore its myriad applications across various industries.

The Basics of Sankey Charts

Sankey diagrams, named after their inventor, Captain Matthew P. Sankey, in 1898, are a type of flow diagram that displays flows between values. Each link in a Sankey chart represents an amount of flow. The width of the link is proportional to the quantity of data flowing through it. This visualization technique is particularly useful for showing the flow of materials through a process into product streams. Sankey diagrams are also helpful in visualizing and understanding energy and water flows, as well as flows of financial data.

Creating Sankey Diagrams

Creating a Sankey diagram is a straightforward process. Here’s a step-by-step guide to get you started:

Step 1: Gather Your Data

Data must be organized into three categories: (1) source node, (2) target node, and (3) the value of the flow between nodes.

Step 2: Organize the Data

Sort your data hierarchically, from top to bottom, so that quantities are presented in a hierarchical order from source to sink. This helps in constructing a meaningful visual flow.

Step 3: Use an Appropriate Tool

While it’s possible to create a Sankey diagram in Excel or even manually drawing it, using specialized software or programming libraries (such as R’s ggplot2 or Python’s matplotlib and seaborn) can significantly enhance the quality of the visualization. These tools offer an array of customization options to make your Sankey chart more engaging.

Step 4: Visualize the Data

Once your data is organized and you have the right tools, drawing the diagram is straightforward. Each link is drawn as an outline; the color should be proportional to the value of the flow.

The Appetizing Example: The Sankey Chart of Beer Conversion

One of the most accessible examples of Sankey diagrams is the one that describes the conversion of ingredients to beer. This simple example from Beer Nut shows how grain, water, and hops are transformed into foam. The use of simple, vibrant colors helps in showcasing the data flow in an incredibly engaging way.

Applications of Sankey Charts

Sankey charts are not limited to mapping beer-making processes; they are a versatile tool with applications across various fields:

Energy Production and Consumption: Sankey diagrams can show the flow of energy from renewable sources like wind, solar, or hydro to consumer usage, illustrating how energy moves and transforms through different stages.
Economy and Finance: For economists, Sankey diagrams are invaluable for tracking the flow of economic data, such as household income, government spending, and international trade.
Environmental Studies: These charts are essential in monitoring and reporting waste and pollution flows, from the source (industrial production, agriculture, etc.) to points of treatment, dispersal, and disposal.
Education: Sankey diagrams can be used to illustrate the flow of students through higher education programs, showing acceptance rates, graduation rates, and any pipeline leaks.
Healthcare: In hospitals, Sankey charts can help in visualizing the flow of patients through various departments, from admission to discharge, enabling better resource allocation.

Conclusion

Sankey diagrams are not just a tool for scientists and data analysts; they are a gateway to understanding complex data sets with a glance. Their ability to capture the flow and movement of data makes them an indispensable tool in data visualization. Whether you’re a scientist trying to convey how energy is converted or a corporate strategist analyzing supply chains, Sankey diagrams offer a clear, engaging, and visually compelling way to communicate data. Unveil the magic of Sankey charts today and see the world through a new lens of data flow.

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.