Sankey diagrams, also known as Sankey flowcharts or.stream charts, have been growing in popularity as an excellent method for visualizing complex flow processes. At first glance, these diagrams may seem daunting due to their unique design, but they are a powerful tool for illustrating the flow of materials or information through a system. In this comprehensive guide, we will delve into everything you need to know about Sankey charts, from their history to the best practices for creating effective flow charts for data visualization.
### A Brief History of Sankey Diagrams
Sankey diagrams were originally developed in the 19th century by a Hungarian engineer, Karl Sankey. Initially used to represent energy flows in industrial processes, the Sankey diagram has since found its way into various fields, including environmental science, finance, and logistics. Despite its age, the Sankey chart remains a vital tool for visual communication due to its ability to convey vast amounts of information in a compact, easily understandable format.
### Understanding the Basics
At their core, Sankey diagrams are made up of a series of arrows that follow the flow of material, energy, or information through a process. The width of each arrow represents the rate of flow, with thicker arrows denoting larger quantities of materials or information. Each arrow is divided into branches, which reflect the direction of the flow and can be interpreted as various process steps or system components.
### Key Components of a Sankey Chart
To create an effective Sankey chart, it is crucial to understand its key components:
– **Arrows:** Represent the flow of materials, energy, or information. They are typically drawn flowing horizontally or at a slight angle to the connecting elements.
– **Branches:** Represent the subprocesses or components involved in the overall process. They connect to the arrows and split or converge depending on the process flow.
– **Tanks or Stocks:** Begin and end the flow representation. They are usually larger than other elements and demonstrate the input or output of the process.
– **Labels:** Provide clear descriptions of the material, process steps, or components shown in the chart.
– **Colors:** Can be used to distinguish different types of materials, phases, or equipment throughout the system.
### Best Practices for Creating Sankey Charts
When it comes to designing Sankey charts, there are several best practices to keep in mind:
– **Start with a Plan:** Define the scope and objectives of your Sankey chart. Determine which variables and quantification methods are important for your data visualization.
– **Choose the Right Software:** There are numerous software options available for creating Sankey charts, such as yEd Graph Editor, Microsoft Excel, and Python libraries like Pandas and Matplotlib.
– **Keep It Simple:** Avoid cluttering your chart with too much information. Each element should contribute to the overall understanding of the flow process.
– **Scale Arrows Evenly:** Ensure that the width of the arrows accurately represents the magnitude of the flow, and scale them evenly to avoid misinterpretation.
– **Be Logical:** Arrange the flow path logically, making sure that the direction of the flow is clear and intuitive.
– **Label Nodes and Arrows:** Provide clear labels for all elements, making it easy for viewers to follow the flow of the system.
### Case Studies and Real-Life Examples
To demonstrate the practical applications of Sankey charts, let’s take a look at a few real-life examples:
– **Environmental footprints:** Sankey diagrams can be used to visualize the environmental impacts of products or processes by illustrating the flow of raw materials, energy, and waste.
– **Financial flows:** In business environments, they help in visualizing budgets, expenses, or investment flows.
– **Supply chains:** Sankey charts can depict the flow of goods, services, and information within a supply chain, providing a clear view of inefficiencies, bottlenecks, and potential areas for improvement.
In conclusion, the Sankey chart is a valuable asset for data visualization, capable of conveying intricate complex flow processes in a clear and concise manner. By understanding the key components, best practices, and real-life examples, you can harness the power of Sankey diagrams to effectively communicate diverse data and processes across a wide range of fields.
