Visual Flow Analysis: Unraveling Data with the Art of Sankey Charts

In the realm of data visualization, there exists a silent symphony of lines and areas that tell compelling stories. One such language of visuals that stands out in the world of data representation is the Sankey diagram, also known as the Sankey chart. It’s been a staple in the repertoire of business analysts and researchers, capturing complex flows of information in a visually digestible manner.

The Sankey chart was invented by Matthew Sankey, an American engineer, in 1933. It’s derived from the field of thermodynamics, a discipline concerned with the efficiency of energy transfer. Thus, it’s no surprise that the original use of these diagrams was to illustrate energy flows in thermal systems. Today, however, its applications extend far beyond just physics and engineering.

The Mechanics of Sankey Chart Creation

Sankey charts consist of a series of nodes connected by colored bars. These bars represent the flow of data. The widths of the bars are proportional to the measurement of the flow—whether it’s a quantitative value like energy consumption or a more qualitative measure such as the number of clients. It’s this relational aspect that provides the foundational framework of comparisons and insights.

Nodes represent the categories or labels of information. These can be as diverse as product categories, decision points, or types of resources.
Links, or the flow lines, represent the direction and amount of data between these nodes.
Bar Width (or thickness) typically ranges between zero and the total available space, reflecting the proportions of the data flows.

Creating an effective Sankey chart involves understanding the data and aiming to provide clarity. Often, the difficulty lies in the aggregation and allocation of data which requires a solid comprehension of one’s subject matter.

Applications Across the Board

The broad applicability of Sankey charts makes them ideal for a wide range of fields and applications:

Energy Systems: In the field of sustainability, Sankey diagrams are common for depicting the energy conversion processes in power plants or in household applications.
Business Analysis: From revenue and cost flows to customer acquisition and sales pipeline analysis, Sankey charts can show a business the sources of income and expenditure on a granular level.
Environmental Planning and Policy: Used for modelling nutrient or water flow systems, these systems help governments and researchers understand the environmental impact and develop sustainable solutions.
Healthcare Management: Sankey charts can offer a visual illustration of patient pathways through healthcare service networks, helping hospitals identify patient traffic flow inefficiencies.
Media & Content Analytics: For creators, Sankey charts can illustrate the flow of audiences through different parts of a piece of content, aiding in understanding viewer engagement.

Challenges and Best Practices

While the beauty of Sankey charts lies in their simplicity, they are not without their limitations and challenges:

Complexities with Negative Flow: Interpreting data with flows in both directions (e.g., income and expenses, or input and output) can complicate matters.
Visual Overload: When nodes or links are plentiful, the chart can become cluttered, detracting from its readability and effectiveness.
Data Granularity: Striking the right balance between too much detail and too little can be tricky. It’s important to communicate the right amount of data to maintain the user’s engagement.

For these challenges, the following best practices are recommended:

Limited Use of Nodes and Links: Group similar data together to avoid confusion, and use icons or abbreviations to represent complex categories.
Negative Flows Clearly Illustrated: Color codes or patterns can be pivotal here. Positive flows can use color codes that are generally interpreted as positive or high, while negative flows could use complementary or contrasting colors.
Use of Tools and Software: Utilize data visualization software to automate the process of creating these diagrams and to provide you with multiple viewpoints.

In conclusion, the art of Sankey charts is both a practical tool and an expressive medium. It simplifies complex data to reveal patterns, understand flows, and make informed decisions. With thoughtful design and insightful applications, the Sankey chart continues to serve as a key instrument in the armory of data-driven narratives.

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.