Sankey and flow charts are popular for illustrating the distribution of work, energy, or resources over time or distance. Among these, Sankey charts stand out for their ability to depict the flow of energy or material through a system with a clear, intuitive visual language. As a comprehensive guide to creating Sankey charts, this post will break down what they are, why they are useful, and how to create them effectively using different tools and software.
What is a Sankey Chart?
At its core, a Sankey chart is a type of flow diagram used to visualize the quantity of flow within a process system. They are designed to show the flow of energy or material through series of processes, highlighting the major transfers of material and energy in a process system. Sankey charts are characterized by their wide and narrow sections, often referred to as “箭头” (arrows), that represent the direction of flow and the quantity transferred between different system components.
Why Use Sankey Charts?
1. **Clarity:** Sankey charts provide an easy-to-understand visual representation of complex systems and processes.
2. **Highlighting Information:** The width of the arrow is directly proportional to the amount of material or energy passing through the system, allowing viewers to quickly identify significant points in the flow.
3. **Comparative Insight:** By visually emphasizing the relative flow of materials or energy, Sankey charts allow for comparative analysis and make it easier to differentiate between different components.
4. **Efficiency:** They help in identifying bottlenecks and inefficiencies within a system, highlighting areas for improvement.
5. **Versatility:** The application of Sankey charts is not limited to energy and material flow but can also be used to illustrate processes and workflows.
Creating a Sankey Chart: Steps to Consider
1. **Collect Data:** Gather information on the flow and quantity of materials and energy that pass through the system. This data is the foundation of the chart and must be accurate.
2. **Select Software:** There are several tools and software available for creating Sankey charts, such as Microsoft Excel, Google Sheets, Omnigraffle, and more specialized tools like桑基图（Sankey Diagram）or桑基图设计器（Sankey Diagrammer）。Choose the one that best suits your needs and skill level.
3. **Setup Your Chart:** Depending on the software, start by setting up the components and their positions on the canvas. This may include nodes for processes, the supply of materials or energy, and the environment.
4. **Create Arrows:** Connect nodes with arrows to show the flow of materials and energy between processes. The width of each arrow should be proportional to the quantity being transferred.
5. **Label and Annotate:** Clearly label nodes and arrows, and include necessary annotations for better visualization and reference.
6. **Refine and Review:** Check for accuracy and consistency, adjusting lines, labeling, and visual representations as needed.
7. **Share your Sankey chart:** Once completed, your Sankey chart can be shared with stakeholders, team members, or the public through exported images, PDFs, or presentations.
Software Overview
– **Microsoft Excel/Google Sheets:** Use data from the table to create flow charts with Sankey diagram plugins like the “Sankey for Excel” add-in or the “Sankey Diagram” app for Google Sheets.
– **Omnigraffle:** A widely used diagramming tool for Mac users, Omnigraffle includes Sankey diagramming capabilities.
– **桑基图（Sankey Diagram）and 桑基图设计器（Sankey Diagrammer）:** These are dedicated Sankey chart software options that provide more detailed features for advanced use.
– **Python libraries:** For those comfortable with programming, libraries like matplotlib and Sankey can be utilized for more customized charts.
By harnessing the flow and data visualization power of Sankey charts, you can effectively communicate the dynamics of complex systems in a manner that is both clear and engaging. Whether for technical analysis or management reporting, this guide provides a roadmap for leveraging Sankey chart tools and techniques to convey crucial information and insights.
