Sankey charts are a type of data visualization that help to illustrate the flow and connections between different categories or entities within a system. They are often used to show how resources, energy, or information move through a complex network, making it easier to understand the relationships and patterns within the system. In this article, we’ll explore the creation and applications of Sankey charts, including their unique features and how they can help untangle complex data sets.
Creating Sankey Charts

Creating a Sankey chart involves several steps, including gathering and organizing data, designing the layout, and using software to generate the visualization. Here’s a brief overview of the process:

1. Collect data: The first step is to gather the necessary data that represents the flow or connections you want to visualize. This data should include the source, destination, and value (such as quantity, amount, or energy) for each flow.
2. Organize data: Once you have the data, you’ll need to organize it in a format that can be easily used to create a Sankey chart. This typically involves creating a table or dataset with columns for source, destination, and value.
3. Design layout: Before drawing the chart, you’ll need to design the layout, including the orientation (horizontal or vertical), the spacing, and any color-coding that will be used to differentiate flows.
4. Use software: There are several tools available for creating Sankey charts, including the popular library, d3.js, as well as commercial software like Microsoft Power BI, Tableau, and others. These tools provide pre-defined templates, shapes, and options for customizing the appearance of the chart.
5. Generate visualization: Once you’ve got everything set up, use the software to generate the visualization. This will include drawing the flow lines, connecting arrows, and labels to clearly show the source, destination, and value for each flow.

Applications of Sankey Charts
Sankey charts have a wide range of applications across different fields and industries, including:

1. Energy systems: Visualize the flow of energy in an electrical grid, the breakdown of energy sources (e.g., fossil fuels, renewables), or how energy is used in industrial processes.
2. Supply chains: Show the flow of goods, materials, or information throughout a supply chain, making it easier to identify inefficiencies, bottlenecks, or opportunities for optimization.
3. Financial flows: Illustrate the movement of money between different accounts, transactions, or investments, helping stakeholders understand the financial structure of a company or investment portfolio.
4. Data pipelines: Display the flow of data through a series of processing steps or transformations, highlighting potential bottlenecks or areas for improvement.
5. Website traffic: Visualize the flow of user traffic on a website, showing which pages are highly visited, how users navigate through the site, and which sources (e.g., search engines, social media) drive the most traffic.
6. Social networks: Represent the flow of information or connections between individuals or groups in a social network, identifying influential nodes, communities, or trends.

Why Sankey Charts?
Sankey charts are particularly useful for understanding complex systems and untangling difficult data sets because they:

1. Provide a clear view of the flow and connections between entities.
2. Allow easy comparison of the magnitude of different flows.
3. Highlight the distribution of resources or energy across categories.
4. Enable the identification of patterns, bottlenecks, or opportunities for optimization.
5. Help communicate complex ideas and relationships to a wide audience.

In conclusion, Sankey charts are a powerful tool for visualizing intricate flows and connections, making it easier to comprehend and analyze multi-dimensional data. By using them, you’ll be able to extract valuable insights from complex systems, simplify explanations to various stakeholders, and ultimately identify actionable improvements for better performance.
Image credits: Illustrations by Alex Kacpyra (modified using VectorMagic)

SankeyMaster

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