Mastering Sankey Diagrams: A Comprehensive Guide to Visualizing Material and Information Flows
Sankey diagrams are specialized visual representations aimed at illustrating the allocation and redistribution of quantities, such as material flow, energy consumption, or information transmission, between various entities. They provide a clear and visually appealing method of quantifying and analyzing processes. If you’re new to using sankey diagrams or wish to enhance your skills, this comprehensive guide offers the essential steps, tools, and insights needed to create and interpret these diagrams effectively.
### What are Sankey Diagrams?
Sankey diagrams, named after their inventor John Boyd Orr, are flow charts that use thick arrows to represent the magnitude of data. The width of the arrows signifies the flow quantity, making it easy to visually identify where the majority of the flow occurs. The origins and destinations of the flows are often depicted at the ends of the diagram, with the flow lines crossing or merging to show interactions.
### Core Principles of Sankey Diagrams
1. **Flow Representation**: The arrows represent the flow of a material, information, or energy. The width of the arrows reflects the volume or intensity of the flow.
2. **Node Placement**: Nodes, or entities, are placed around the diagram. Nodes can symbolize various things, from specific organizations or geographical regions to inputs, outputs, or processing units.
3. **Material or Information Flow**: The flow starts at a ‘source’ node, where the data originates, and ends at one or more ‘sink’ nodes. Nodes in between represent where the material, information, or energy goes for processing or storage.
4. **Visual Clarity**: Sankey diagrams aim to maintain a clear and aesthetically pleasing layout, ensuring that the diagram remains easily understandable, especially when dealing with complex system compositions.
### Components of a Sankey Diagram
1. **Nodes**: These are the visual elements representing the entities (nodes) involved in the flow, where the data starts or ends. Nodes can be simple or more complex, depending on the depth of the information to be conveyed.
2. **Edges**: The flow lines connecting nodes. Their width is proportional to the magnitude of the flow between nodes.
3. **Labels**: Descriptions or titles attached to nodes and edges to clarify the nature of the units and flows.
### Tools for Creating Sankey Diagrams
#### 1. Online Tools
– **Sankey Diagram Maker** by ChartGo: A user-friendly platform that offers several styles for sankey diagrams.
– **Sankey Generator** by Lucidchart: Enables the interactive creation and visualization of flow diagrams.
#### 2. Software Tools
– **Microsoft Excel**: Using add-ons like Sankey Visualizer, Excel can create relatively simple Sankey diagrams.
– **R and Plotly**: R’s `sankeyR` package or `plotly` library allows for the creation of interactive sankey diagrams.
– **Tableau and PowerBI**: These business intelligence tools offer extensive customization for sankey diagrams with robust data handling capabilities.
### Best Practices
– **Organize Data**: Start by properly segmenting and organizing your data into categories that correspond to the diagram’s nodes and flows.
– **Simplify Complexity**: Use colors and labels to differentiate flows and nodes, enhancing readability but avoid cluttered and confusing visual schemes.
– **Interactivity**: For digital representations, consider incorporating interactive elements that allow users to explore the data in more detail, such as zooming, filtering, or highlighting specific paths.
### Conclusion
Mastering the art and technique of creating sankey diagrams requires a combination of data organization, careful design, and the right tools. By adhering to best practices and utilizing the appropriate resources, you can effectively communicate complex flow data in an engaging and easily digestible manner. Whether used in academic research, corporate reporting, or process optimization, sankey diagrams offer a powerful tool for visualizing and understanding intricate systems.
