Unraveling Complexity with Sankey Charts: A Guide to Visualizing Flows and Information
Sankey charts, a fascinating data visualization tool, play a critical role in simplifying complex information. This article aims to provide an overview of what Sankey charts are, how they work, and their unique capabilities in transforming complicated data sets into understandable representations.
### What are Sankey Charts?
Sankey charts are a specialized type of flow diagram named after Captain Matthew Henry Phineas Riall Sankey, who introduced this visual format in the 19th century. They display the flow of quantities, such as energy, goods, data, money, etc., by showing the source and destination of the quantities and the volume of flow in each direction.
### How Sankey Charts Work
Sankey diagrams use arrows (or bands of ‘wires’) with varying widths to represent the quantity of flow, with the width of the arrows proportionate to the amount of flow they depict. This technique makes it easy to comprehend volume, the direction of flow, and the significance of connections in large datasets. Nodes, which represent sources, destinations, or intermediate points, are connected by these arrows, providing a clear picture of how data or entities move from one point to another.
### Visualizing Flows and Information
Sankey charts excel in visualizing intricate systems where data moves through various steps, components, or processes. Here are key areas that benefit from Sankey diagrams:
#### Energy Systems
They illustrate the flow of energy sources, such as power generation from coal, solar, and wind, to distribution systems and the end-users. This visualization aids in understanding the energy efficiency and environmental impact of different scenarios.
#### Supply Chain Logistics
In business and economics, supply chain complexity can be overwhelming. Sankey charts demystify this by showing raw materials, manufacturing processes, and end-products flow from supplier to consumer, revealing bottlenecks and inefficiencies.
#### Data Flows
In information technology, analyzing web traffic patterns, data movement between servers, or user journey on websites through interactive Sankey diagrams can unveil insights that streamline system performance and enhance user experience.
#### Economic Activity
Highlighting economic transactions, employment flows, and wealth distribution within an economy, Sankey charts showcase the connections and impacts of various sectors and stakeholders.
### Key Characteristics and Best Practices for Designing Sankey Charts
#### Consistent Node Ordering
Maintaining consistency in node order, particularly at the start and end of the diagram, greatly improves readability and the interpretability of the data flow.
#### Color Usage
Color coding nodes and arrows can enhance differentiation and group similar data for easier identification, but care is needed to prevent overuse, which might clutter the visualization.
#### Edge Widthing
Proportional edge widths effectively communicate the volume of flow. Careful scaling ensures that the widths are meaningful without overwhelming the visual space.
#### Data Precision
Balancing detail and clarity is crucial. Including too many data points can clutter the chart while filtering out too much detail makes the chart less informative.
#### Interactive Elements
When possible, adding interactive features like hover effects, clickable elements, and drill-down capabilities to Sankey charts can improve interaction and usability.
### Conclusion
Sankey charts provide an invaluable tool for deciphering complex data flows and visualizing intricate systems. By leveraging their unique design to illustrate volume, direction, and context, these charts enable better decision-making in diverse fields ranging from energy systems and economic analysis to IT networks and logistics. Their proficiency in making the abstract tangible makes Sankey diagrams a powerful addition to any data analyst’s or systems designer’s toolkit.
