# Unleashing the Power of Flow: A Comprehensive Guide to Creating and Interpreting Sankey Diagrams
Sankey diagrams are an innovative way to visually depict flows or data that pass from one point to another. This article serves as a comprehensive guide designed to assist individuals interested in creating and interpreting Sankey diagrams, emphasizing their utility and the skills necessary to utilize them effectively.
## What Are Sankey Diagrams?
Sankey diagrams first emerged as an industrial engineering tool, designed to represent resource flow diagrams in a manufacturing plant. Today, their application has vastly expanded beyond its engineering roots and can be seen across various fields including, but not limited to, economics, logistics, environmental science, and public policy.
Sankey diagrams represent flows, where the width of the arrows, typically rectangles or lines, indicate the data quantity flowing from one point to another. This unique feature gives them an inherent ability to visualise high-volumes of data very intuitively.
## Why Use Sankey Diagrams?
Among the various reasons they are widely popular, two stand out significant:
**1. Visualization of Large Amounts of Data:** One of the biggest advantages of Sankey diagrams is their ability to simultaneously handle and visualize large amounts of data. Complex datasets that would be hard to interpret in tabular or simple graphical form can be easily deciphered using this type of diagram, thanks to their representation of data in flow form.
**2. Clearly Displaying Relative Importance:** The width of the links in the diagrams directly corresponds to the amount of data flowing between the points, making it easy to identify the most significant flow pathways. This visually intuitive feature allows for a quick understanding of the relative sizes of various flows, emphasizing what data sets are most significant.
## How to Create Sankey Diagrams:
### 1. Data Collection
Before creating a Sankey diagram, ensure you have a structured dataset with the following information for each flow:
– **Source**: Where the flow originates from.
– **Sink**: Where the flow ends.
– **Value**: The size or volume of the flow associated with the connection between source and sink.
### 2. Software Choice
Sankey diagrams can be created using various tools depending on the complexity of the data and the level of graphical design expertise you aim to achieve. Popular choices include:
– **Microsoft Excel**: For simpler projects, Excel offers straightforward ways to create basic Sankey diagrams utilizing its built-in chart capabilities.
– **Tableau**: Known for its powerful data visualization tools, Tableau is highly recommended for creating sophisticated Sankey diagrams with complex data flows and visual customization options.
– **Visio and Draw.io**: For more intricate designs, users can create Sankey diagrams using these vector graphic editors where detailed control over shapes, connections, and aesthetics can be achieved.
### 3. Design Process
**Step 1**: Organize your data into columns for source, sink, and value.
**Step 2**: Use your chosen tool to create a Sankey diagram template by adding nodes for your sources and sinks.
**Step 3**: Connect the nodes using arrows, adjusting their widths according to the value data provided. In Excel, this might require manual adjustments to the arrow widths. In professional tools like Tableau, the software automatically adjusts the widths based on the data provided, streamlining the process.
### 4. Review and Adjust
Once the basic diagram is created, review it for readability and adjust the layout or color scheme if necessary. Ensure all nodes are clearly labeled and arrows are easily distinguishable.
### 5. Finalize and Publish
After making any adjustments, save your work and, if applicable, export the visual as an image or embed it directly into a report or presentation.
## How to Interpret Sankey Diagrams:
Interpreting Sankey diagrams primarily involves understanding the visual elements, specifically the sizing, orientation, and labeling of the nodes and arrows.
### 1. Sizing of the Arrow
The thickness or width of an arrow corresponds to the quantity of flow it represents. The wider the arrow, the more significant the flow.
### 2. Arrow Orientation
Arrows typically stem from sources and head towards sinks. The direction offers intuition on the nature of the flow.
### 3. Node Labels
Understand what each node represents. Typically, labels include key identifiers such as a location, material, or type of transaction.
### 4. Reading Between the Lines
The composition of connections between nodes reveals flow complexity and reveals underlying patterns that might not be evident from raw data. The presence of multiple paths in parallel can indicate multiplicity or competing flows, and dead ends can signal where flows terminate without continuation.
## Conclusion
Sankey diagrams offer a powerful way to visualize and interpret data flows, from the macroeconomic shifts in energy consumption to the intricate supply chains in global logistics. By understanding when and how to use these diagrams, you can effectively communicate the movement and distribution of any type of resource, providing deep insights into systems that flow-based visualizations bring to the surface.
Sankey diagrams, while simple in concept, require careful handling with the right tool and an approachable data structure, making them an indispensable tool for researchers, data analysts, and decision-makers across various industries.
