Mastering the Concept and Applications of Sankey Diagrams: A Visual Analytics Tool for Effortlessly Tracking Complex Flows
Introduction
Sankey diagrams, also known as Sankey flow diagrams, have become one of the most popular visual analytics tools for representing flows and movements of information, materials, energy, and other resources. They are named after Dr. Matthew Henry Phineas Riall “Pheo” Sankey, an engineer who developed the first flow diagram to illustrate the energy loss in an engine. Their unique and detailed visual representation allows users to efficiently understand complex systems, trends, and patterns that would be obscured or otherwise difficult to interpret from conventional data display methods.
Concept and Definition
Sankey Diagrams can be defined as a type of flow diagram that utilizes arrows or ‘links’ to visually capture the movement or flow of a resource between two or more nodes (usually characterized by a source, an intermediary node, and a sink in network concepts). Each link has different widths that are designed to visually depict the scale or quantity of the flow – the thicker the line, the greater the volume of the flow.
Elements of a Sankey Diagram
1. Source: The starting point for the movement or flow of a resource. This node provides the total quantity that will be distributed or transformed throughout the diagram.
2. Intermediary Nodes: These nodes serve as points of transformation or recombination where the flow can split, merge, or have different volumes passed between them before reaching their final destinations.
3. Sink: The end point of the flow, it represents where the resource is consumed, transformed, or lost.
4. Links: These are the primary visual elements that connect the source, intermediary nodes, and sinks. Their thicknesses are proportional to the magnitude of the flow they represent, allowing users to quickly grasp which processes contribute more to the total flow.
5. Labels: These identify the type of flow or specific variables at each node or connecting link. They can often include descriptive text, values, or categories.
Applications in Various Domains
Sankey diagrams are highly versatile and are widely used in different sectors to illustrate complex systems effectively:
1. Energy Analysis: Sankey diagrams are instrumental in visualizing energy flows and losses in power systems, industrial plants, buildings, and various other energy-intensive systems. It helps users understand energy efficiency and the impact of each component on the overall system performance.
2. Data Analytics & Reporting: In business analytics, Sankey diagrams help in tracking the flow of resources such as customers, transactions, or data through different stages of the business process. This can assist businesses in identifying inefficiencies and improving marketing or sales strategies.
3. Urban Planning & Resource Management: These diagrams are useful for managing and visualizing the environmental aspects such as waste management, resource allocation, and traffic flow. They help in enhancing urban efficiency and sustainable practices.
4. Biology & Ecology: In ecology, Sankey diagrams can illustrate the movement of water, nutrients, and energy in ecosystems or food webs, aiding in ecological studies and conservation efforts.
5. Environmental Impact Assessment: They are used to evaluate and visualize the environmental impact of various projects or industries. This helps stakeholders to make informed decisions about mitigating negative effects on the environment.
Benefits of Sankey Diagrams
Sankey diagrams offer several advantages in the realm of data visualization:
1. Enhanced Understanding: By clearly visualizing the quantity and direction of flows in a given system, Sankey diagrams help users grasp complex relationships and trends that might be difficult to discern from tabular data or text information.
2. Comparative Analysis: They allow for easy comparison of different sets of flows, enabling the identification of patterns, anomalies, or areas that require improvement or optimization.
3. Improved Communication: With their intuitive design, Sankey diagrams can make complex systems and data more accessible to stakeholders, including those with limited technical expertise. This facilitates shared understanding and quicker decision-making processes.
4. Better Design Insights: For architects and urban planners, Sankey diagrams provide valuable insights into energy usage patterns, material flows, and transportation networks. This can lead to more efficient design solutions and sustainability improvements.
Conclusion
In an era where data and analytics play a critical role in almost every aspect of decision-making, Sankey diagrams serve as an essential tool for deciphering complex flows and patterns. By providing a clear, visual representation of resource distribution, energy consumption, or processes in various fields, these diagrams enable users to make data-driven decisions, optimize operations, and innovate effectively. The versatility of Sankey diagrams makes them an invaluable resource for researchers, analysts, and decision-makers seeking to master and apply the concept and applications of this visual analytics tool.
