Sankey charts are a unique and visually compelling way to represent flows of data or material between different nodes. They were invented by Matthew Henry Phineas Riall Sankey and are best suited for showing the magnitude and direction of flow between different entities. This article aims to help you understand the creation and applications of Sankey charts.
Creation of Sankey Charts
-
Define the Data: The first step involves collecting and organizing the data that you wish to represent. This data typically includes:
- Sources: Where the flow originates.
- Sinks: Where the flow ends.
- Flows: The magnitude of the data moving between sources and sinks.
-
Node Identification: Nodes in Sankey charts represent entities (sources, sinks, or intermediate nodes) and are usually depicted as rectangles or circles. Each should carry labels and, possibly, additional attributes relevant to the data.
-
Link Formation: Edges, or links, represent the flow from one node to another. Their width is proportional to the magnitude of the flow. This visual representation makes it easy to identify where the most significant flows occur.
-
Layout Determination: Deciding the layout is crucial as it affects how the chart is perceived and understood. Common layouts include node-link diagrams and flow maps, with each having its own advantages depending on the specific data and audience.
-
Design and Customization: Use colors, hover effects, and legends to enhance the readability and aesthetic appeal of your chart. Tools like Tableau, R (with packages like ‘ggraph’ or ‘sankey’), or Python libraries (networkx, plotly.sankey) offer various ways to design these charts.
Applications of Sankey Charts
-
Energy Usage: Sankey charts are often used to show energy consumption patterns in a building or a power grid, illustrating where energy is lost or efficiently used.
-
Supply Chains: Businesses use Sankey charts to visualize supply chains, illustrating the flow of materials or products from suppliers to manufacturers to retailers, thus visualizing the efficiency and potential bottlenecks in the supply chain.
-
Network Flows: In computer networks, Sankey charts can represent data traffic flow, showing how data travels between different routers or servers.
-
Sustainable Systems: In environmental science, these charts are used to show the flow of resources or pollution between ecosystems, countries, or organizations, highlighting areas for improvement in sustainability practices.
-
Public Transportation: Urban planners can use Sankey charts to depict passenger flow in public transportation systems, aiding in route optimization and identifying congestion points.
Advantages of Sankey Charts
- Visualization of Complex Flows: It simplifies understanding of complex flow patterns, making them accessible to a general audience.
- Emphasis on Magnitude: By adjusting the width of the links, it visually emphasizes the most significant flows, which is crucial for data analysis.
- Comparative Analysis: It allows for easy comparison of different flow patterns, which is particularly useful when analyzing changes over time or across different systems.
Challenges
However, creating effective Sankey charts also presents some challenges:
– Clutter: Too many nodes or flows can lead to a visually crowded chart, making it difficult to interpret data correctly.
– Data Complexity: Handling multidimensional data within a Sankey diagram can be challenging, requiring sophisticated algorithms for layout and optimization.
– Simplicity vs. Detail: Striking a balance between simplifying complex data and providing sufficient detail for informed decision-making is critical.
Conclusion
Sankey charts offer a versatile and powerful tool for data visualization, providing insights into flows that would be difficult or impossible to discern through other chart types. Whether analyzing energy usage, supply chains, or network traffic, these charts serve as a bridge, making complex data flow understandable at a glance. As with any visual representation, careful consideration of data, design, and layout is necessary to ensure that the chart is as informative as it is elegant.
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.
