Flowing Through Data: The Art and Science of Sankey Diagrams

Sankey diagrams have been around for nearly two centuries, offering a unique and powerful way to visualize the flow of things. They’ve gained popularity among various disciplines, from industrial to ecological systems, to demonstrate how energy, water, and materials flow through networks. As a cross between art and science, Sankey diagrams transform complex data into intuitive visuals that help people understand the dynamics of energy systems and material flows. This article delves into the art and science of creating Sankey diagrams and explores their diverse applications.

The Genesis of Sankey Diagrams

The Sankey diagram was invented by German engineer Karl Sankey in the 1890s. This was during the early stages of the Industrial Revolution, an era marked by an increased understanding of energy flow and efficiency for both the production of power and mass manufacturing. Sankey sought a way to clearly represent the energy efficiency of machines and systems. His innovation turned the traditional bar or flowchart on its head, highlighting the direction and magnitude of energy flow as vectors that converge or diverge.

The Structure of a Sankey Diagram

Sankey diagrams have a distinct structure:

Arrows represent the flow of energy or material through the process.
Tanks or reservoirs represent the supply and end points of the process.
Fittings or lines represent different levels of the process.
Width of the arrows is proportional to the magnitude of the flow: the wider the arrow, the more energy or mass being moved in that flow.

The core strength of Sankey diagrams is that they highlight the major sources, uses, and losses of energy or materials in a system at a glance. This visualization helps identify opportunities for optimization and efficiency improvements.

Creating Sankey Diagrams

Creating a Sankey diagram involves the following steps:

Data Collection: Quantify the energy or material flows in your system you wish to visualize.
Process Identification: Determine the different stages or processes in the system.
Flow Direction and Magnitude: Decide on the direction and magnitude of each flow. The arrow widths must be calculated based on the data provided in step 1.
Diagram Layout: Place every element in the diagram and arrange them to reflect the flow between processes and to each reservoir.
Adjustment and Fine-Tuning: Once the basic structure is in place, make necessary adjustments to perfect the layout and clarity.
Symbolization and Annotation: Finally, add symbols and annotation such as labels, legend, and units of measure to ensure the diagram is easy to understand.

Modern software makes the creation of Sankey diagrams much easier than it was in Sankey’s day, though it still requires careful consideration of the underlying data and understanding the system being visualized.

The Art of Sankey Diagrams

The art of Sankey diagrams lies in their ability to convey information efficiently. Key points include:

Clarity: Each element in the diagram should be easily recognizable and clearly explained.
Visual Hierarchy: Important information should be more prominently displayed than less significant details.
Balance: The arrangement of elements should create a harmonious layout without overwhelming the viewer.
Consistency: Use consistent color schemes and line styles throughout the diagram.

The Science of Sankey Diagrams

When designed correctly, Sankey diagrams are an excellent way to:

Visualize Efficiency: Demonstrate where energy or material is wasted or where there is an opportunity for improvement.
Identify Bottlenecks: Spot processes that might be causing inefficiencies in the overall flow.
Compare Systems: Analyze different systems to understand how they stack up in terms of efficiency and waste.
Educate Others: Create clear visual explanations for colleagues, clients, or the public to understand complex concepts.

Applications of Sankey Diagrams

Sankey diagrams have far-reaching applications in various fields:

Industry: Tracking energy flows in manufacturing and assessing overall efficiency.
Transportation: Observing energy consumption in various modes of transport.
Building Design: Illustrating the energy pathways of green buildings.
Agriculture: Visualizing nutrient and water flows within ecosystems.
Finance and Economics: Modeling the exchange of goods and services in a supply chain.

Flowing through the realm where data meets art and science, Sankey diagrams continue to play a vital role in making sense of our complex, interconnected world. Whether monitoring the flow of resources in a factory or understanding the intricate web of global markets, these diagrams provide a clear window into the efficiency and effectiveness of systems across countless industries.

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.