Flow Visualizations Unveiled: The Lush Lyrics of Sankey’s Symphony

In the world of data visualization, there’s an art form that captures the essence of complex systems and makes them elegantly comprehensible. Sankey diagrams — elegant, often colorful rivers of data — embody this art. The concept, named after Engineer William Playfair’s contemporary, Edvard Munch, has evolved into a powerful tool for illustrating the flows of materials, energy, and finances within intricate systems. Renowned physicist John Snow’s innovative mapping of cholera outbreaks paved the way for this method, named after another engineer, Matthew S. Sankey, whose diagrams continue to harmonize the often chaotic notes of data in the 21st century.

The Genesis of Sankey Diagrams

William Sankey, a 19th-century Irish engineer, first introduced his eponymous charts in the 1880s to depict the efficiency of steam engines. A Sankey diagram visually represents the magnitude of flow in a process, which makes it an invaluable tool for understanding how materials or energy moves through a complex system or network.

These diagrams present flow as an arrow whose width is proportional to the flow rate. The direction of the arrow indicates the flow path, while the width depicts the quantity of flow through the process. Sankey diagrams uniquely emphasize the relative size of flows within a system, making it easier to understand the system dynamics and identify inefficiencies.

The Art and Craft of Sankey Chart Creation

Crafting a Sankey diagram is a process of balance and creativity. Here’s an overview of the steps involved in creating one:

Define the System: Understand the flow of interest within the system you’re analyzing; this could be the flow of water, electricity, or finances, for example.
Identify the Process: Break down the system into its components, where the flow originates, how it changes, and how it is ultimately lost or gains elsewhere in the system.
Collect Data: Gather data on the flow rates involved in the described system. This requires precise measurement and calculation.
Set Up the Sankey Diagram Software: There exists specialized software, like SankeyEditor, SankeyMidi, or Python libraries such as python-sankey and plotly, dedicated to creating Sankey diagrams.
Create the Sankey Elements: Divide the diagram into channels through which materials or energies flow (e.g., input, transformation, output). These channels are the “ribs” of the diagram, around which you’ll construct your ‘flows”.
Connect Flow Channels: Connect each channel, forming ‘arrows’ that represent the flow from one process to the next.
Size the Arrows According to Flow Rates: Arrange the size of each arrow in proportion to the actual flow rate it represents. Flow channels are usually kept narrow to prevent the diagram from becoming cluttered.
Color Code and Label: Assign colors to different flows and label each section, making sure the audience understands what that portion of the system does.
Adjust and Iterate: Often, the initial creation of a Sankey diagram requires adjustments. Ensure the information is clearly presented and easy to follow, considering the viewer’s ability to interpret the diagram correctly.
Final Review: Review the diagram to check for consistency, balance, and clarity, then finalize the design.

Applications of Sankey Diagrams

Sankey diagrams have a diverse array of applications due to their ability to succinctly depict the flow of variables within complex systems:

Energy Flow: Illustrate the energy pathways in thermal systems, including heat transfer and conversion processes.
Material Flow: Analyze the movement of resources in industrial processes, revealing how materials are transformed and wasted.
Finance: Track capital and financial flows within businesses and institutions, showing how assets and debts are distributed.
Biography and Genetics: Visualize the genetic information flow across a species’ biology or the narrative flow in a life story.
Information Systems: Demonstrate the flow of data in computer systems and networks.
Choreography: In dance and stage production, they can represent the flow of movement or the direction of characters’ paths.

By harnessing the power of Sankey diagrams, we can turn vast amounts of data into stories that flow like a symphony — telling a beautiful story about the intricate connections and transactions at play, whether in a chemical reactor, a company balance sheet, or the lifeblood of our cities’ energy infrastructures. In a world where complexity reigns supreme, Sankey diagrams offer us the chance to conduct these symphonies with our data, revealing the hidden melodies that guide our modern world.

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.