Home » Everything You Ever Wanted to Know About Sankey Charts

Everything You Ever Wanted to Know About Sankey Charts

by Melanie Peterson

The Sankey diagram shows how different quantities are distributed in between items at two or more stages. In other words, it shows the flow of various resources. The key that helps reading and interpret the Sankey diagram is knowing that the width is directly proportional to the represented quality.

In this technique, the flow is involved in the process, and the width is proportional to the flow rate. Therefore, the Sankey diagram helps visually showing the flow involved in these resources.

First drawn by the Irish engineer, Captain Matthew H.R. Sankey, it’s one of the most amazing visually representing data methods. Sankey got its name from the Capt. Who used this diagram to differentiate and compare the energy of steam engines. Earlier, this type of diagram was also used by a French engineer to visualize the Russian campaign of Napolean.

Then, in twenty century, Austrian Mechanical engineers use it to keep an eye on passenger cars’ energy and power losses. With this evidence, it is clear that the Sankey has been used for many years to resolve different problems. Today, this diagram is used to visualize data and to keep track of the flow that is involved in the business process.

Why Should You Use The Sankey Diagram?

With a plethora of information available through data, it becomes difficult to keep track of everything. Therefore, to simplify the complex data and to identify the relationship between various data elements, Sankey is used. 

The diagram is more than just bar graphs and charts, as it gives you the additional information that is missing from them. Its emphasis on the major flow or different transfers in the system, thereby helping you to show which flows are better and which ones are causing the waste or emission.

The width lines in these flow diagrams are related to various nodes that are proportional to the KPIs. It gives users the flexibility to get insights into various data. Here are other reasons why you should use the Sankey diagram:

Better Communication:

One of the most important reasons for using a Sankey diagram is that it can communicate the energy flow process. It offers easy communication of the energy flow process and gives you real-time knowledge of the data to have better insights.

Improved Outreach:

Sankey diagrams can accommodate various applications and processes very easily. This also means, if you got stuck in any application, don’t worry; try this diagram, and you will have a visual representation of everything. It will help you have better outreach.

You Can Detect The Inconsistencies:

With the Sankey flow diagram, you can easily identify the loopholes, discrepancies, and inconsistencies in the process. You can detect and identify issues and eliminate them in the shortcoming process before they turn something big.

Multiple Viewing Levels:

Sankey has various viewing levels, which means you can have a high-level view and easily see the issues’ details. Also, you can generate an interactive view to identifying the flaws and more. If you want a detailed view of your issues, Sankey has various tools that let you view and share everything with ease. You can also determine the level of depth that is required in your work.

How To Make A Sankey Diagram:

Step1: Design:

Before creating a Sankey diagram, you first need to identify your purpose and what you want to show your audience. Therefore, to save you from rebuilding the diagram or building an ineffective one, here are few questions you should ask yourself:

  • Are you using the Sankey jut for the exploratory data analysis?
  • Do you want to create or tell a story using things, or you just want to promote a specific action?
  • Who is your specific audience
  • What experience does your audience have in data visualizations
  • What does your audience want- whether it’s ROI, effectiveness, efficiency, comparison by brands/city, or efficiency.

Once you know all the above things, you can start your Sankey and outline things you want to visually show. While creating the diagram, also keep these things in mind:

  • Create alternate and different ways to communicate your points
  • Outline group related inputs and outputs
  • Use colors to highlight various transactions
  • Emphasis on important things like position, length, color, direction, shape, or anything

Step 2: Code:

Once you are done identifying the important metrics, the next step comes in code. Start coding the Sankey to get the desired result.  In the code, you can adjust the path lengths to separate them from the main flow or adjust the length of space between the inputs and outputs.

How to use the Sankey diagram?

The usage of Sankey depends on the two major things, i.e., Link and Nodes. Nodes are like a bar in the chart, and each bar’s height depends on the value of the Sankey. The connection between the nodes is called links, which help to indicate the flow. The directed flow is made between two different nodes, called processes. 

Furthermore, the flow indicated the energy, money, and materials. The flow also has arrows that are used to indicate the quantity of flow. Sankey is a great alternative to charts and bar graphs as they are gaining huge popularity in engineering and other industries, where data visualization is the most important thing.

On the contrary, a rough and poorly drawn Sankey will hide the important and actionable results instead of showing the profits. Also, they will look more complex to audiences and are more difficult to understand. So, get a clear idea, gather the results and then draw a Sankey diagram.


If you are looking for an amazing and visually attractive tool to show your data and insights into the business, the Sankey diagram is for you! But, with this, you just have to keep in mind that you need to limit your data analysis and break them into multiple single sessions. By using the tool the most, you can visualize things like material flow, cash flow, energy losses, and more. Plus, you can also add your own visual graphics to make it more understandable and visually appealing.

Related Articles

Leave a Comment