Sankey charts are a unique and informative way to visualize directionality and flow in data. Essentially, they are flow diagrams that use the width of the arrows to represent the quantity of flow within the system. Often used in fields such as energy, logistics, finance, and environment science, Sankey diagrams can present complex processes and relationships with clarity and aesthetic appeal. In this introduction, we will dive into what Sankey charts are, how they work, and when they are best applied.
A Brief History
The concept of Sankey charts can be traced back to 19th-century engineer санкт петербург казино | играть онлайн by Mining Engineer Marcus Aurelius Sankey, who designed a diagram to illustrate relationships between coal-burning steam engines and locomotives. Since then, their relevance has multiplied, and they have become a staple in various industries.
Understanding Sankey Diagrams
At their core, Sankey diagrams consist of nodes (representing processes, locations, or categories) and links (arrows that show the flow between these nodes). These diagrams are characterized by a few distinct properties that set them apart from other visualization tools:
– **Width of Arrows:** As mentioned previously, the width of each arrow is proportional to the magnitude of the flow it represents. This immediately gives viewers a sense of the data’s importance or scale.
– **Flattenning on Horizontal Axis:** Sankey diagrams typically use a horizontal axis to show the overall flow of materials or information. The directionality of the flow is maintained by varying the arrow’s slanting angle.
– **Efficiency and Pathways:** Sankey charts can highlight inefficiencies or bottlenecks in a process by illustrating the directionality of energy, resources, materials, or money spent.
– **Stack or Flow:** There are usually two Sankey diagram types, depending on whether you want to represent “stacks” (a section showing a series of events of the same type) or “flows” (where only the first and last events are shown).
How to Make a Sankey Diagram
Creating a Sankey diagram involves breaking down complex systems into nodes and links, using software such as Microsoft Excel, Tableau, or specialized Sankey diagram tools. Here are the general steps:
1. **Identify the System:** Determine the various components or nodes within the system you are trying to visualize.
2. **Quantify Flow:** Assign a numerical value to the flow between each pair of nodes.
3. **Define Nodes and Links:** Draw nodes (with or without labels), and connect them with arrows to represent the links (flows).
4. **Scale Elements:** Adjust the width of the arrows to be proportional to the magnitude of the flows between nodes.
5. **Arrange Nodes:** Reorganize the nodes to make the diagram more readable and aesthetically pleasing.
6. **Color Coding:** Use colors to differentiate between various types of flows, such as energy, materials, and waste.
When to Use Sankey Charts
Sankey diagrams are best employed when you need to:
– **Illustrate processes with multiple inputs and outputs**
– **Identify inefficiencies and bottlenecks**
– **Visualize the relationships between system components**
– **Compare different processes or systems**
– **Analyze the flow of resources or energy across complex systems**
The Bottom Line
Sankey charts are invaluable tools for those seeking to convey the nuances of flow and directionality in their data in an engaging and informative manner. Their unique visual approach not only aids in grasping complex systems but also provides a starting point for further analysis and insights. Whether you’re a data analyst, researcher, or just someone with an interest in data visualization, Sankey diagrams can help you tell better stories with your data.
