Applications of Sankey Plots

Oct 13, 2025 by wbrum.org 32 views

Introduction

Sankey plots are a powerful visualization tool used to represent the flow of data between different nodes in a network. They are particularly useful for displaying complex relationships between entities, such as the flow of energy, materials, or information. However, when dealing with unequal node sizes, creating a Sankey plot can be a challenging task. In this article, we will explore the concept of Sankey plots, their applications, and provide a step-by-step guide on how to create a Sankey plot with unequal node sizes using R and Ggplot2.

What is a Sankey Plot?

A Sankey plot is a type of flow-based visualization that displays the flow of data between different nodes in a network. It is characterized by its use of arrows to represent the flow of data, with the width of each arrow proportional to the magnitude of the flow. Sankey plots are often used to display complex relationships between entities, such as the flow of energy, materials, or information.

Applications of Sankey Plots

Sankey plots have a wide range of applications in various fields, including:

Energy analysis: Sankey plots can be used to display the flow of energy between different components of a system, such as the flow of electricity between different parts of a power grid.
Material flow analysis: Sankey plots can be used to display the flow of materials between different stages of a production process, such as the flow of raw materials through a manufacturing facility.
Network analysis: Sankey plots can be used to display the flow of data between different nodes in a network, such as the flow of information between different computers on a network.

Creating a Sankey Plot with Unequal Node Sizes

Creating a Sankey plot with unequal node sizes can be a challenging task, especially when dealing with large datasets. However, with the use of R and Ggplot2, it is possible to create a Sankey plot with unequal node sizes.

Step 1: Install and Load Required Libraries

To create a Sankey plot with unequal node sizes, we need to install and load the required libraries. The following libraries are required:

ggplot2: This library provides a comprehensive set of tools for creating high-quality graphics in R.
sankey: This library provides a set of tools for creating Sankey plots in R.

# Install required libraries
install.packages("ggplot2")
install.packages("sankey")
library(ggplot2)
library(sankey)

Step 2: Prepare Data

To create a Sankey plot with unequal node sizes, we need to prepare our data. The data should be in a format that can be easily read by the Sankey plot function. The following is an example of how to prepare the data:

# Create a sample dataset
data <- data.frame(
  source = c("A", "B", "C", "D", "E"),
  target = c("F", "G", "H", "I", "J"),
  value = c(10, 20, 30, 40, 50)
)
print(data)

Step 3: Create Sankey Plot

Now that we have prepared our data, we can create a Sankey plot with unequal node sizes. The following is an example of how to create a Sankey plot:

# Create a Sankey plot
sankey_plot(data, node_size = "value")

Step 4: Customize Sankey Plot

The Sankey plot function provides a set of options for customizing the plot. The following is an example of how to customize the Sankey plot:

# Create a Sankey plot with custom options
sankey_plot(data, node_size = "value",
            node_color = "blue",
            node_label = "Node Label",
            node_fontsize = 12,
            link_color = "red",
            link_width = 2)

Example Use Case: Host-Parasite-Pathogen Network

One example use case for a Sankey plot with unequal node sizes is the visualization of a host-parasite-pathogen network. In this network, the host is the central node, and the parasites and pathogens are the peripheral nodes. The flow of data between the nodes represents the interaction between the host and the parasites/pathogens.

The following is an example of how to create a Sankey plot for a host-parasite-pathogen network:

# Create a sample dataset
data <- data.frame(
  source = c("Host", "Parasite 1", "Parasite 2", "Pathogen 1", "Pathogen 2"),
  target = c("Parasite 1", "Parasite 2", "Pathogen 1", "Pathogen 2", "Host"),
  value = c(10, 20, 30, 40, 50)
)
sankey_plot(data, node_size = "value")

Conclusion

In this article, we have explored the concept of Sankey plots, their applications, and provided a step-by-step guide on how to create a Sankey plot with unequal node sizes using R and Ggplot2. We have also provided an example use case for a host-parasite-pathogen network. With the use of R and Ggplot2, it is possible to create high-quality Sankey plots with unequal node sizes, making it easier to visualize complex relationships between entities.

References

ggplot2: Wickham, H. (2016). ggplot2: Elegant Graphics for Data Analysis. Springer.
sankey: This library provides a set of tools for creating Sankey plots in R.
Host-Parasite-Pathogen Network: This is a complex network that represents the interaction between the host and the parasites/pathogens.
Sankey Plot for Unequal Node Sizes: Q&A =============================================

Introduction

In our previous article, we explored the concept of Sankey plots, their applications, and provided a step-by-step guide on how to create a Sankey plot with unequal node sizes using R and Ggplot2. However, we understand that there may be some questions and concerns that readers may have. In this article, we will address some of the frequently asked questions (FAQs) related to Sankey plots and unequal node sizes.

Q: What is the difference between a Sankey plot and a flowchart?

A: A Sankey plot and a flowchart are both used to display the flow of data between different nodes in a network. However, a Sankey plot is a type of flow-based visualization that displays the flow of data between different nodes in a network, with the width of each arrow proportional to the magnitude of the flow. A flowchart, on the other hand, is a type of diagram that displays the flow of data between different nodes in a network, but it does not display the magnitude of the flow.

Q: How do I choose the right node size for my Sankey plot?

A: The node size for a Sankey plot can be chosen based on the magnitude of the flow between the nodes. A larger node size can be used to represent a larger flow, while a smaller node size can be used to represent a smaller flow.

Q: Can I customize the appearance of my Sankey plot?

A: Yes, you can customize the appearance of your Sankey plot using various options available in the Sankey plot function. You can change the color, font size, and other properties of the nodes and links to make your plot more visually appealing.

Q: How do I handle missing values in my data?

A: Missing values in your data can be handled by using the na.rm argument in the Sankey plot function. This argument can be set to TRUE to remove missing values from the data before creating the plot.

Q: Can I create a Sankey plot with multiple levels of nodes?

A: Yes, you can create a Sankey plot with multiple levels of nodes by using the node_size argument in the Sankey plot function. This argument can be set to a vector of values to represent the node size at each level.

Q: How do I save my Sankey plot as an image file?

A: You can save your Sankey plot as an image file by using the ggsave function in R. This function can be used to save the plot as a PNG, JPEG, or other image file format.

Q: Can I create a Sankey plot with interactive elements?

A: Yes, you can create a Sankey plot with interactive elements by using the plotly library in R. This library provides a set of tools for creating interactive plots, including Sankey plots.

Q: How do I troubleshoot common issues with my Sankey plot?

A: Common issues with Sankey plots can be troubleshooted by checking the data for errors, ensuring that the node sizes are correctly calculated, and adjusting the plot settings as needed.

Conclusion

In this article, we have addressed some of the frequently asked questions (FAQs) related to Sankey plots and unequal node sizes. We hope that this article has provided you with a better understanding of how to create and customize Sankey plots using R and Ggplot2.

References

ggplot2: Wickham, H. (2016). ggplot2: Elegant Graphics for Data Analysis. Springer.
sankey: This library provides a set of tools for creating Sankey plots in R.
plotly: This library provides a set of tools for creating interactive plots in R.