Flowing Data: Unveiling Insights with Sankey Charts

Sankey diagrams, a type of flow chart, are a powerful tool in the visualization toolkit for showcasing flows or networks between different points within a system. While they may seem straightforward, Sankey diagrams are versatile and can provide deep insights into complex data sets. In this article, we’ll explore how to create Sankey charts, their applications, and the insights they can uncover.

What are Sankey Charts?

Sankey diagrams, named after Captain Matthew P. Sankey, an American engineer who used them in the late 19th century to visualize energy flows in steam engines, are a type of flow chart consisting of interconnected bars. They are especially useful for visualizing flow networks, such as energy, materials, cash, pollutants, and people, between different points in a system. Sankey diagrams are designed to represent a flow or transfer from one point to another, showcasing the volume and direction of the flow at each step.

Creating a Sankey Chart

Creating a Sankey chart can be a bit technical initially but is increasingly accessible with the advent of various digital tools. Here’s a basic guide on how to create one using R Studio, a popular tool for data visualization:

1. Install R and R Studio: If you haven’t already, download and install R and R Studio on your computer.

2. Load the Sankey Diagram Package: You can use the ggsankey package, which is an extension of the ggplot2 package. You’ll need to install this package first if you haven’t already.

   R
install.packages("ggsankey")
library(ggsankey)


3. Prepare Your Data: Your data should be in a tidy format, where each row represents a link (or transition) in your network. Key columns include source (the node from which the flow originates), target (where the flow goes), and value (the quantity of the flow).

4. Create the Sankey Chart: Here’s a basic example on how to create a simple Sankey chart.

   “`R

   Example Data

   data <- data.frame(
   source = c(“Start”, “Start”, “Start”, “Process 1”, “Process 1”, “Process 2”),
   target = c(“Process 1”, “Process 2”, “End”, “End”, “End”, “End”),
   value = c(50, 30, 20, 20, 10, 10)
   )

   Create the Sankey Diagram

   ggplot(data, aes(x = 1, y = value, axis1 = source, axis2 = target, label = value)) +
   geomlink() +
   geomsankey(colour = “black”) +
   theme_minimal()
   “`

5. Customize: Feel free to customize your chart further with colors, labels, and more based on your data and needs.

Applications of Sankey Charts

Sankey diagrams are not just aesthetically pleasing; they are also highly informative. Their clear representation of flows makes them ideal for a wide range of applications, including:

• Energy Flow and Efficiency Analysis: Sankey charts are widely used in energy management to show how much energy is lost at each step in a process, helping to identify inefficiencies.

• Financial Transfers and Cash Flows: In finance, these charts can map the sources and uses of funds across different accounts or investments.

• Data Flow and Networks: They can visualize the movement of internet traffic, data breaches, or the spread of information across different platforms and sources.

• Transportation Systems: Sankey diagrams can show the routes and flows of people, goods, or vehicles within a city’s transportation system or between cities.

• Water Systems and Pollution: In environmental science, Sankey charts are used to track the flow of water and pollution through drainage systems or through various wastewater treatment processes.

Conclusion

Sankey diagrams are a powerful tool for data visualization, offering a clear and insightful way to explore flow networks. Whether for energy efficiency, financial planning, or monitoring environmental impact, these charts provide a visual language that helps us understand complex systems more deeply. As digital tools continue to evolve, the accessibility and use of Sankey diagrams in various fields are likely to grow, making them a valuable resource for anyone working with flow data.

SankeyMaster

SankeyMaster is your go-to tool for creating complex Sankey charts . Easily enter data and create Sankey charts that accurately reveal intricate data relationships.