Unleashing the Power of Flows: A Journey Through Sankey Charts
Sankey charts are a powerful visualization tool that help in depicting the flow of quantities in an entire system or process. Originating from the work of Scottish engineer (and ship owner) Matthew Henry Phineas Riall (M.H.P.) Sankey, these diagrams are typically used to show transfer of energy or material between systems or process stages.
What is a Sankey Chart?
A Sankey chart is a type of flow diagram that displays how the amount or magnitude (or ‘flow’) of a quantity changes as it passes through various stages, in both a vertical and horizontal direction. It features colored arrows or bands that have widths proportional to the flow quantity they represent. These arrows start from one value, transit across various nodes and lines, and lead to the final destination value, all the while allowing a visual assessment of the quantity distribution and flow patterns within the system.
Creating Sankey Charts
To create a Sankey chart, use a visual analytics software tool such as Tableau, Power BI, or R with libraries like ggplot2 for R or sankeychartjs for web applications. The process involves:
1. Data Preparation:
Gather data on the flow (quantity) and the pathways between these flows. Ensure the data is clean and includes all necessary information such as source, destination, and the quantity for each flow.
2. Choosing the Visually Effective Layout:
The layout can influence how easily a user can understand the flow patterns. Common layouts include:
- Vertical Layout: Can show a significant number of flows without overlapping too many on the screen.
- Horizontal Layout: Best for a lesser number of flows or less detailed information since it shows the process from start to end in a line.
- Circle Layout: Great for visualizing cyclic processes with clear, aesthetically pleasing results.
3. Drawing the Connections:
The main feature of a Sankey chart’s success lies in its ability to visually represent transitions from one state to another. Connections are drawn with varying widths that represent the value of the flow. The software of choice provides tools to create and visually adjust these connections.
4. Adding Labels and Legends:
Labels for each node and flow should add clarity to the chart. Including a legend can help explain the color codes used across the chart, making it easier to understand the different flows.
Applications of Sankey Charts
Sankey charts, with their clear visual depiction of quantity flow and distribution, are applicable across numerous fields where a system’s flow dynamics are essential for understanding:
- Environmental Science: Mapping energy consumption between different sources and sinks, environmental flows between ecosystems.
- Economics and Finance: Visualising trade flows between countries, energy or resource transactions within an organization.
- Engineering: System flow diagrams showing materials or energy passage in chemical processes or infrastructure networks.
- Healthcare: Tracing disease spread, blood flow between organs, or patient movement through healthcare facilities.
- Supply Chain Management: Understanding material or product movement within a manufacturing pipeline or distribution channels.
Whether in understanding complex biological systems or guiding policy decisions on resource allocation, the Sankey chart’s ability to clearly illustrate the movement and distribution of quantities allows for insight and decision-making in diverse fields. It’s a powerful tool in the data visualization toolkit, showing its utility in bringing clarity to the interconnections and dynamics within systems and processes.
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.
