Sankey charts offer a visually compelling method to observe the dynamic relationships and flow of energy, materials, or finances across systems or processes. Unlike traditional bar and line graphs, Sankey diagrams illustrate the magnitude of real-world flows, with the width of the connecting arrows increasing or decreasing according to the amount of material they represent. They’re a powerful tool for visualizing efficiency and the relationships across various components of a system.
Let’s explore them through a detailed, step-by-step guide, helping you to create your own effective flow visualizations with a Sankey chart.
### Step 1: Establishing the Purpose
Before diving into the design process, it’s crucial to understand why you want to create a Sankey chart. Whether you are analyzing the efficiency of energy conversion, the flow of traffic patterns, or the distribution of finances, define the purpose clearly to guide your data and design decisions.
### Step 2: Data Collection
The process begins with collecting or acquiring relevant data. For an effective Sankey chart, your data should represent a flow — something that moves across or through the system you’re studying. It could be the amount of energy used, materials transferred, or information processed.
### Step 3: Analyzing the Data
You’ll need to determine the entities in your system and how they interact. For instance, in an energy system, sources of energy, conversions, and sinks should be identified and quantified. This analysis phase helps you to understand the structure of your Sankey diagram.
### Step 4: Choosing the Software
Selecting the right software is critical to designing a Sankey chart effectively. There are several software packages and online tools available that are specifically designed for creating Sankey diagrams, including Microsoft Excel, Power BI, Gephi, and SankeyMill.
### Step 5: Building the Layout
Start by sketching the basic layout of your Sankey chart. This involves:
– **Deciding the Orientation:** Sankey charts can be either horizontal or vertical.
– **Identifying Nodes:** These are the starting and ending points of the flow. Mark them clearly.
– **Defining Arrows:** These represent the flow itself. Begin with a solid arrow indicating the source and an open arrow indicating the sink.
### Step 6: Adding Data and Connections
In this stage, plug in your data and begin establishing connections between nodes. Each arrow should reflect the actual or relative flow size. Use consistent units in your data to maintain accuracy and readability.
### Step 7: Adjusting Widths
Adjust the width of the arrows to represent the volume of flow. Ensure that the width of the arrows changes consistently, with no gaps or overlaps, to accurately reflect the flow magnitudes without confusing the reader.
### Step 8: Fine-Tuning the Diagram
Look for ways to enhance clarity:
– **Add a Legend:** Explain what different colors or styles on the arrows represent if necessary.
– **Label Nodes:** Ensure each node is clearly labeled with sufficient detail for understanding the flow involved.
– **Scale Arrows:** Make sure that the width of the arrows corresponds to the volume of flow, representing your data accurately and making the chart informative.
### Step 9: Review and Iterate
Check your Sankey chart for any inconsistencies or errors. Also, ensure that the design is intuitive and users can interpret the flow without confusion. If needed, revisit earlier steps and adjust your diagram accordingly.
### Step 10: Share and Document
Once satisfied with your Sankey chart, share it and provide any necessary documentation or explanation to ensure that others can understand the flow and insights it represents.
An effectively created Sankey chart can be a game-changer in data visualization, helping you to distill complex interrelationships and draw actionable conclusions. By following these steps, you’ll be well on your way to understanding and utilizing the power of Sankey charts in your own flow visualization endeavors.
