Many people do not have much information about alluvial diagrams vs. Sankey diagrams. This is mainly because the two are closely related and have superficial similarities, making it challenging to identify the difference. However, according to the report published in 2021, a Sankey diagram is completely different from an alluvial diagram. The only thing that marks the difference is the underlying superficial assumptions many believe in.

In addition, there are many things that people need to understand to differentiate the two diagrams. This article covers multiple aspects that can help you understand the difference between the two.

What is an Alluvial Diagram?

An alluvial diagram is dedicated to showcasing different forms of changes that form the flow of materials, cost, energy, and any other resource that can be easily measured within a particular duration. When you look at an alluvial diagram keenly, you will realize its name comes from alluvial fans. The diagram was generated from the alluvial fan considering how it looks and operates.

The fans on the diagram are formed naturally when streaming platforms of water deposit soil. When analyzing data in an alluvial diagram, you will realize that variables are outlined on the vertical axis, which is the parallel side. In addition, there are values that are always outlined on all the axes using blocks. Note that the height of the blocks reciprocated the height of the flow of the stream as well as the size of the container.

The field depicts the size of the elements outlined within the block. Also, it’s directly connected to the stream field. On most occasions, the alluvial diagram is considered an alternative form of the parallel sets only because it’s used to present categorical variables within the data you present. The diagram is mainly used to display trends and time in the long run. 

If you have a diverse set of data that you intend to process and generate insights, the alluvial diagram can help you process the data and compose a compelling data report that you can utilize to facilitate the smooth running of your daily operations. You only need to ensure that you have accurate information to analyze and identify any possible trends that will help you going forward.

What is a Sankey Diagram?

A Sankey diagram is a data visualization tool used to display the flow of days from one point to another within a system. The diagram has connections known as nodes, while the connections between the nodes are known as links. When you have a mapping activity that needs you to execute, you can choose to use a Sankey diagram since it has a comprehensive room that you can use to analyze and process data.

Also, if you want to display a many-to-many mapping system, this data visualization tool has your back covered. Google Analytics uses a Sankey diagram to display how traffic moved from one page of the website to the next. The diagram was invented by Captain Sankey, who introduced it to the data market through a popular publication showcasing the flow of energy in a steam engine when composing his practical report.

What Leads to Confusion Between the Two Diagrams?

It’s no secret that many people find it challenging to identify their differences. When you look at the two diagrams, you will realize that the nodes are represented using bars that are placed in a vertical manner. In both diagrams, the height of the bats represents the idea of the volume count within the system. This brings out some similarities between an alluvial diagram and a Sankey diagram.

The available links between the nodes have curves that are similar to the nodes’ general height that perfectly encode the count or the volume, similar to how the node’s height operates. When using the two diagrams, you will need to highlight the stripe within all the diagrams. This will help you identify the width of the stripe within different points across the diagram.

All these features reveal the similarity between an alluvial diagram and a Sankey diagram. You need to be keen on incorporating these features into your diagram to help you clearly outline the data.

Difference Between Alluvial Diagram and Sankey Diagram

In most cases, the alluvial diagram displays the appearance of quantities from one state to another across different processes. On the other hand, a Sankey diagram operates similarly to a streamlined flow chart used to depict quantitative values within every phase of the data visualization process.

When you look closely at the two diagrams, you will realize that there is a lack of consistency in how the nodes are spread across the entire chart within the lines. The line sets on a Sankey diagram are uniform in terms of length and analytics. This is contrary to the alluvial chart, whereby there are a lot of variations on how the nodes are positioned.

The alluvial diagram is mainly used to process multi-dimensional data. The diagram mainly focuses on analyzing the proportions and frequencies between different data dimensions and how they are closely related. A Sankey diagram is primarily applied in the cases that need quantity visualization between different stages within the entire process.

When using a Sankey chart, you can easily identify the parts that have a dominant contribution and areas where the quantity gets lost within the process. This gives you a clear picture of the entire data process. 

Tools Used to Make Sankey Diagrams

There are different tools that you can use to generate a Sankey diagram that transparently outlines all your data. Creating a Sankey diagram using the manual approach is a daunting task many people find impossible. Below are automatic tools that can help you generate an appealing Sankey chart that can help you visualize your data in easy steps.

Google Charts

Google charts offer you a simple approach that you can use to generate a Sankey chart in just a few clicks. If you get access to Google charts, you have the freedom to use attractive charts and data tools depending on your priorities. The process is easily customizable since everything has been made automatic. All you need to do is to outline the data you intend to visualize, and the Google chart algorithm will have the entire job done on your behalf.

Microsoft Excel

Excel is one of the most popular tools that you can use to generate a Sankey diagram. However, this software does not have the Sankey diagram option by default. You need to install a third-party app that will make your work easier. In this case, you need to install ChartExpo, which has multiple features that make generating the chart easier. Once you have installed the app, you only need to import your data to Excel and open the app. Upon clicking the Sankey chart option, you will be presented with the diagram with all your data outlined. 

Tools Used to Create Alluvial Diagrams

You can use different tools to create an alluvial chart that displays all your preferred data. You can use any of the tools below!

Alluvial Diagram Generator:

The alluvial diagram generator is an advanced web-based app that can help you generate an alluvial diagram in simple steps. All you need to do is to upload your data and generate your preferred output. Once the diagram I generated, you can opt to download or share it depending on your preferred needs.


This tool has multiple customization features that make it easier to generate an alluvial chart in simple steps. However, the free version of the tool does not give you room to download the final data output unless you have already made payments.


The alluvial diagram and the Sankey diagram have many things in common. However, the common features do not mean that the two are similar in any way since they are used to perform different tasks.  To uncover the difference, you need to consider evaluating the capabilities of the external and internal attributes to give you a clear picture that makes the two different. Once you have an idea about all the features and attributes of the diagrams, you will be in a better position to outline the similarities and differences and how they are used.

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