# Decoding the Flow: A Comprehensive Guide to Creating and Understanding Sankey Charts
Sankey diagrams, also known as Sankey flow charts or Sankey diagrams, are a visual representation used to illustrate the distribution of quantities between two or more entities. They are particularly useful for understanding and communicating complex information about energy, matter, fluid, and people flows in an easy-to-digest graphical format.
## The Essence of Sankey Charts
A Sankey chart consists of nodes connected by arrows (flow lines) that vary in width, reflecting the magnitude of the flow at any given point in the system. The diagrams depict the entry points, the pathway, and the exit points of flow, hence the name “flow.” This makes them particularly effective for conveying relationships where the importance or magnitude of the data is central.
## When to Use Sankey Diagrams
Sankey diagrams are ideal for the following scenarios:
### 1. **Visualization of Material/Resource Flows**
Utilizing a supply chain, material flows, the transport of substances like fluids or electricity, the flow of energy, or the movement of people through different departments or locations in an organization.
### 2. **Understanding Financial Flows**
Illustrating the flow of money or resources between different accounts, departments, or partners in a company structure.
### 3. **Analyzing Complex Energy Systems**
Comparing energy consumption, transfers, or output at different levels within an energy system.
## How to Create a Sankey Diagram
### Step 1: Gather Data
Collect data on the origins, transits, and destinations of your flow. Ensure the data includes start nodes, end nodes, and the flow’s intensity or volume.
### Step 2: Determine Node Sizing
Each node typically represents a starting or ending location, and the size might represent the quantity being transported between two points, depending on the diagram’s purpose.
### Step 3: Design the Layout
Sketch out a basic layout or use an existing template, placing nodes as needed. Ensure that the entire flow is contained in your diagram, with nodes representing sources, transits, and destinations, and arrows connecting them with varying widths.
### Step 4: Apply Width to Arrows
Widths of the arrows must accurately represent the magnitude of the flow data (volume or quantity).
### Step 5: Add Labels and Legends
Include labels on nodes to describe the content or category. A legend may provide additional context, especially for diagrams with many indicators or colors.
### Step 6: Polish and Revising
Refine the design ensuring clarity and readability. Make sure that the diagram doesn’t become cluttered, which might happen with too many flows or categories. Ensure accuracy in data presentation.
## Key Features and Considerations
– **Direction of Flows**: The direction along the arrows provides a clear understanding of the flow path.
– **Width Proportions**: The thickness of the arrow indicates the quantity or intensity of the flow, visually highlighting significant data points.
– **Color Coding**: Using color to differentiate between various types of flows can aid in quick data segregation and interpretation.
– **Readability**: Ensure the diagram isn’t overcrowded. Limit the number of lines and categories to keep the chart readable and informative.
– **Interactivity**: For digital diagrams, adding interactive elements such as hovering over an arrow to reveal more data can enhance user engagement and understanding.
## Conclusion
Sankey diagrams are a powerful tool for visualizing flows, whether they’re data-based, resource routes, or informational pathways. By leveraging the visual weight of arrows, size and color to communicate data volume and nature effectively, these charts transform complex information into easily understandable narratives. Whether you’re illustrating the intricate pathways of a supply chain, the life cycle of financial transactions, or the distribution of resources, Sankey charts offer a comprehensive solution to making your data flow accessible and comprehensible to a wide audience.
