Sankey charts are a unique and powerful type of data visualization that can help to unravel complex systems and flows. First developed in the 19th century by Sir John Snow to represent the spread of the cholera epidemic in London, the Sankey chart has since become a versatile tool used in a variety of fields to help us understand connections and flows within systems. In this article, we will explore the basics of Sankey chart creation and discuss some of the many applications where they have proven to be extremely useful.
What is a Sankey Chart?
A Sankey chart is a type of flow diagram that shows the distribution and flow of quantities through a system. The chart presents the flow using links or arrows whose thickness is directly proportional to the value they represent. Unlike other types of flow charts, Sankey diagrams often include nodes that represent entities in the system and links that connect them, visually illustrating the connections between inputs and outputs.
Key Components of a Sankey Chart
- Nodes: These are the points where the flow enters or exits the system. Nodes can be labeled to represent different types of entities, such as sources, intermediaries, or destinations.
- Links: These are the flow paths that connect the nodes and visually represent the transfer of elements from one node to another. Links are often color-coded to help distinguish between different types of flows.
- Arrows: The thickness of each arrow represents the magnitude of the flow it represents. Thus, larger arrows indicate a higher value or volume of flow.
- Balanced Flows: The total flow into a node should equal the total flow out of it (except for the source and sink nodes which may receive or send more than they receive or send, respectively). This helps in maintaining consistency and understanding the flow dynamics.
Creating a Sankey Chart
To create a Sankey chart, you need to have data that breaks down the flow between different nodes. This data should include:
– Node IDs: Identifying the type of each node (e.g., Source, Category 1, Category 2).
– Flow amounts: The quantity of flow moving from one node to another.
– Categories: To differentiate and color-code the flows based on specific criteria.
Software tools like Microsoft Power BI, Tableau, or data visualization libraries in Python (such as Plotly) offer robust capabilities to create Sankey charts. These tools typically require you to input your data in the following format:
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Node ID A | Node ID B | Flow
or
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Source | Destination | Flow Amount | Category
Once the data is prepared, you can follow the steps given in the software documentation to create and customize the Sankey chart according to your needs.
Applications of Sankey Charts
- Energy Flows: Sankey charts can be used to visualize the distribution of energy through various transformation stages, such as from fossil fuels to electricity, or from renewable resources to their use in a manufacturing process.
- Waste Streams: In environmental studies, Sankey diagrams are invaluable for mapping the production to disposal of waste materials within supply chains, indicating where pollution or waste management improvements can be most impactful.
- Business Processes: Companies in various sectors use Sankey charts to understand the movement and distribution of goods, services, or resources across their value chain, helping to optimize logistics and reduce costs.
- Economic Flows: Economists utilize Sankey charts to explore intricate relationships between different economic sectors, such as trade flows between countries or the allocation of budget across various government departments.
- Social Media Influences: Analyses of influencer marketing and social media propagation of content can benefit from Sankey charts to illustrate the flows of influence or information across platforms.
Conclusion
Sankey charts are a powerful tool for visualizing complex flows and systems in various disciplines. By leveraging the visual strength of Sankey diagrams, analysts and decision-makers can gain insights into system dynamics, identify inefficiencies, and make more informed decisions. Whether it’s understanding energy conversion processes, mapping waste streams, or analyzing social media impacts, Sankey charts offer a clear and compelling way to communicate critical information. As technology for data visualization continues to advance, the use and impact of Sankey charts are likely to expand even further, making complex flows more accessible to everyone.
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.
