Sankey diagrams are a type of flow visualization that are used to represent the flow of quantities between different nodes or categories. They were first developed in the 19th century by a Scottish civil engineer named Alexander Bain, but have gained renewed popularity in recent years due to their ability to convey complex data relationships in an intuitive and visually appealing way.
In this article, we will explore the power of Sankey diagrams, their creation, and some of their applications in various fields.
Understanding Sankey Diagrams
Sankey diagrams are named after Alexander Bain who developed them in the 1860s as a way to visualize flows of materials and energy. Since then, they have become a popular tool for visualizing many different types of flows, including data flows in computer science, traffic flows in transportation, and financial flows in economics.
At the heart of a Sankey diagram is a flow network represented by nodes and links. The nodes are typically arranged in two rows, with the source nodes on top and the sink nodes on the bottom. Each node represents a category or a specific location that is connected by links, which show the flow or movement between the categories.
The width of the links is proportional to the amount of flow passing through them, so the larger the link, the more significant the flow. This makes it easy to see at a glance which flows are the most important, and to understand how the flow is partitioned between different categories.
Creating Sankey Diagrams
Creating a Sankey diagram involves several steps, which can be broadly divided into two categories: data preparation and visualization.
Data Preparation
The first step in creating a Sankey diagram is to prepare the data. This involves collecting the data that you want to visualize and organizing it in a format that can be easily imported into a data visualization tool.
There are many software tools available for creating Sankey diagrams, such as Tableau, Power BI, or online tools like Sankey diagram generators. Each tool has its own method for importing data, so you will need to consult the documentation for your chosen tool to learn how to import your data.
Typically, you will need to prepare your data in a format that includes a list of nodes, a list of links, and the flow values for each link. The format of this data will vary depending on the tool you are using, but it generally involves specifying the source and destination nodes for each link, as well as the flow value.
Visualization
Once you have prepared the data, you can use your chosen tool to create the Sankey diagram itself. This involves selecting your data and clicking a button or dragging and dropping your data onto the visualization canvas. The tool will then automatically generate a Sankey diagram based on your data, including the nodes and links, the node labels, and the link widths.
You can then customize the appearance of the Sankey diagram using options such as colors, labels, and layout. You can also add additional elements such as tooltips, legends, and titles to make the diagram more informative and easier to understand.
Applications of Sankey Diagrams
Sankey diagrams have a wide range of applications in various fields where flows of quantities are to be visualized. Here are some examples:
Energy Consumption: A Sankey diagram can be used to visualize the flow of energy used at a household level, showing the different sources of energy and highlighting the most significant flows. It can also be used to compare energy usage across different households or time periods.
Traffic Analysis: Sankey diagrams can be used to visualize the flow of traffic between different locations, such as toll booths or urban intersections, and to identify bottlenecks in the traffic flow.
Data Visualization: Sankey diagrams can be used to visualize the flow of data in computer networks or to show the flow of influence between different individuals or organizations in a social network.
Financial Decision-making: Sankey diagrams can be used to visualize the flow of money in financial systems, such as supply chains, to better understand the value chain and optimize the allocation of resources.
Conclusion
In conclusion, Sankey diagrams are a powerful tool for visualizing flows of quantities, making them easier to understand and providing insights into complex data relationships. By combining the data preparation and visualization steps in your chosen tool, you can create high-quality Sankey diagrams that are both informative and visually appealing. Whether you are analyzing energy consumption, traffic flows, data networks or finance systems, Sankey diagrams are an indispensable tool for gaining insights and making data-driven decisions.

SankeyMaster

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