Sankey Diagram: A Comprehensive Guide

Any process that involves a flow of some kind can be represented graphically with the help of a Sankeys. A Sankey chart is a way to go if you want to show how information flows from one set to another. The corresponding parts, or nodes, are known as a network’s connections or links. As such, a Sankey diagram is your best choice if you need to depict a many-to-many mapping between two areas or different paths through a set of steps.

The nodes and links in a Sankey graph can be given whatever color you choose. Depending on the user’s preferences, nodes and connections can take on various color schemes. As such, they can stand in for data transmission from one entity to another. Nodes refer to the entities from which data flows; the origin node is the entity from which the flow began, and the destination base station is the entity where the flow is expected to conclude.

Fields of Use

The fields of process engineering, energy management, facility management, and process control, amongst others, use these diagrams.


In 1898, Captain Matthew Henry Phineas Riall Sankey drew the first energy diagram as a series of arrows whose lengths were directly proportional to the quantity involved. Previously, Charles Joseph Minard had used a similar map to make sense of Napoleon’s 1812 Russian Campaign. Meanwhile, that was the only chart that Captain Sankey ever made. As a result, over time, they were forgotten. Alois Riedler (1850-1936) first used such graphs to assess the efficiency of passenger automobiles in the 20th century.

This chart type is widely used to visualize data and may be seen in applications as diverse as energy management and material flow analyses.


A Sankey chart depicts the energy balance or resource flows better than a bar, pie chart, or flow diagram. The largest and most significant data points in a system are highlighted in Sankey diagrams. Money allocation is a multi-step process that may be portrayed visually, straightforwardly, and understandably. This method is quite helpful for showing how components share resources. In addition, data visualization can help spot inconsistencies, such as those introduced by improper measurement or miscommunication.

The diagram is a visual representation of complicated processes that allows you to draw attention to a specific part of the process or an essential resource. As such, a Sankey is highly recommended whenever a group decides to allocate resources like time, money, or energy.

Sankey diagrams also have the bonus of accommodating various zoom settings. Users may produce dynamic views, zoom in for finer details, or obtain a bird’s eye overview. Many solutions allow you to share the ability to drill down with a colleague who enjoys doing so, with no additional effort required from the creator. And the depth may be adjusted to suit your needs in advance.

A Practical Example: How Much Energy Does a Passenger Car Use?

This Sankey shows the energy equation for a typical car. Much energy put into forwarding motion is lost as heat only at the wheels. The car’s extra occupants may be identified, too. Meanwhile, both raw numbers and percentages are provided to help visualize the data. The arrows are all clearly labeled by color, and their sizes are determined by the amounts of fluid they represent.

A Sankey diagram is a flow chart that may show the flow of resources, money, or energy. System, manufacturing technology, and supply chain flows may all be represented by vectors that scale with the amount of data sent. In addition, it is backed up by a range of color flow volumes, each of which may be easily understood. Finally, Sankeys can effectively convey all information and messages to any audience, including members of a development team.