Flow Visual Fun: The Alluring World of Sankey Charts Unpacked

Flow charts have been a visual staple since the birth of data science, but within this realm of information visualization, few tools are as intriguing or as underappreciated as Sankey charts. Characterized by their dynamic, flowing lines and the way they depict proportional quantities of energy or material through a system, Sankey charts offer a unique approach to understanding the flow of things. This article delves into how Sankey charts are created, their various applications, and their charm in visual storytelling.

Understanding Sankey Charts

A Sankey chart is a type of flow diagram that illustrates the quantity or magnitude of energy or material through a process system. Designed to show the largest and most important flows as prominent, they are best used when you want to highlight the most significant components of a process or system.

Key Features of Sankey Charts:

Continuous Lines: These charts have lines that are continuous and only ever increase in thickness, never decrease—to represent the flow of materials, energy, or data through a system.
Vector Forces: Flow direction is represented by an arrow indicating a force of movement.
Proportional Width: The width of each flow line is proportional to the quantity of material or energy carried; thicker lines signify higher flows.
Branches and Nodes: Nodes, or intersections, are where the flow splits or combines.Branches of the chart represent the separate flows within the system.

The Craft of Sankey Chart Creation

Sankeys can be manually drawn or created with software, but their construction shares a few fundamental steps.

Data Collection: Begin by gathering your raw data. For a Sankey chart to be effective, the data needs to represent real quantities of energy or material as you want to convey.
Selection of a Vector: Decide on the vector you want to use. This could be energy flow, material flow, or, as in information systems, data flow.
Identify Flows and Nodes: Using your data, identify the inputs, outputs, and intermediate flows. Nodes are points where these flows converge or diverge.
Determine Energy or Flow Ratios: If necessary, calculate the proportion between each type of flow to ensure your Sankey chart accurately depicts relative quantities.
Sketching the Chart: Start drawing. Begin with main sources and end points, creating nodes where the flows diverge or converge. Then, draw flows that represent these quantities proportional to the substance flowing through.
Adjusting Widths and Styles: Adjust the widths of the flow lines to represent their flows relative to each other. You might also alter the color, style (dashed or solid), or opacity for additional emphasis.
Finalizing and Refining: Once all components are drawn, use a tool like Adobe Illustrator or specialized software for fine-tuning, including adding labels and legend.

Apps and Software for Sankey Charts

The process of creating a Sankey chart by hand can be time-consuming and challenging. Various software solutions have been developed to streamline this process:

Tableau: The renowned data visualization tool offers Sankey chart capabilities as part of its suite.
Gephi: This is a powerful tool for network visualization, including Sankey diagrams.
Sankey Diagrams Illustrator Script: An Illustrator script designed to help you create Sankey diagrams with more ease.

Applications of Sankey Charts

Sankey charts are widely used in a variety of fields to analyze complex flow processes:

Energy Systems: They can depict the energy flows within a power plant or transportation system.
Environmental Studies: To visualize the flow of emissions in industries or the distribution of waste materials.
Business and Economics: Illustrating the flow of money, resources, and information through an organization or market.
Network Analysis: To map the flow of data, energy, or materials, in telecommunications networks, for instance.

The Future of Sankey Charts

With the growing need for understanding the dynamic nature of complex systems, Sankey charts are unlikely to fade into obscurity. They offer a visual storytelling format that can elegantly communicate the intricate dynamics that otherwise would be difficult to comprehend.

Moreover, advancements in software and new tools will probably lead to even more sophisticated Sankey charts that can handle increasingly complex datasets and provide deeper insights into the flow of energy, materials, and information.

By harnessing the power of Sankey charts, we can better comprehend the unseen flows that define our interactions within our world and, ultimately, make better decisions that reflect the reality we want to build. As data visualization continues to evolve, the alluring world of Sankey charts promises to remain a powerful and unique resource for those who seek to visualize the invisible.

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.