Sankey charts are a powerful and visually compelling method for visualizing flows and transfers between entities. These charts are named after their inventor, Scottish engineer and physicist Matthew Henry Phineas Riall “Phineas” Sansom, who first used a similar diagram in 1898, although the modern variant known today was introduced by the engineer Malcolm Sanyk in 1951. The term “Sankey” has since become a standard in the field and is used widely in data visualization.
Creation of Sankey Charts
To create a Sankey chart, one must first gather data that includes the source, target, and flow volume between different nodes. This data can be sourced from various domains, such as economics, energy use, material flow, or social network analysis. The key steps in creating a Sankey diagram are:
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Data Collection: Gather data on the flow volumes, origins, and destinations. This data should be summarized in a way that makes it easy to apply to the chart’s links and nodes.
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Node Definition: Identify the entities or categories that will be represented as nodes. These entities could be countries, materials, processes, or any other elements that are part of the flow system.
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Edge Configuration: Connect the nodes using edges that represent the flows between entities. The width of each edge should reflect the magnitude of the flow, which is proportional to the data volume specified for that particular connection.
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Design and Aesthetics: Arrange nodes and connections in a way that is aesthetically pleasing and easy to understand. This often involves spreading out nodes and edges, and sometimes using color coding or labels to enhance the readability of the chart.
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Software Tools: Utilize software tools designed for creating Sankey charts, such as Microsoft Excel with add-ons like Plotly or Sankey Diagrams for Excel, Tableau, R with the ‘diagram’ or ‘networkD3’ packages, or Python libraries such as Matplotlib and Plotly.
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Review and Iterate: Ensure the chart accurately represents the data and that the flow volumes are correctly indicated. Sometimes multiple iterations are needed to achieve clarity and balance.
Applications of Sankey Charts
Sankey charts find applications across various industries and research domains due to their ability to effectively communicate complex relationships and flows at a glance. Here are a few prominent use cases:
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Energy and Sustainability: Visualize energy usage, production, and consumption, showcasing where energy goes and how energy efficiency impacts a company or an entire country’s energy consumption.
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Economics and Finance: Analyze trade flows between countries, investments, or spending in economic sectors. For instance, showing the money flow between different industries within a country or internationally.
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Health Sciences: Track the flow of patients through various stages of care or show the pathways of information within a clinical trial, emphasizing the connections between diagnostics, treatments, and outcomes.
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Engineering and Manufacturing: Showcase material flows in production lines, revealing inefficiencies or identifying the main sources and destinations for materials.
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Social Sciences: Visualize data flows in social networks or demographic information, such as migration patterns or data exchange between different age groups.
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Environmental Sciences: Represent carbon flows, water usage, or pollution sources and sinks, highlighting environmental impact and potential solutions.
Sankey charts are not just a tool for data visualization; they are a powerful narrative instrument that can help stakeholders understand complex systems and make informed decisions. By leveraging the right software and creative design principles, these charts can become even more impactful in diverse fields, driving insights and innovations through data-driven storytelling.
SankeyMaster
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