Sankey diagrams, with their unique and visually intriguing appearance, are rapidly gaining popularity as an effective way to convey complex data flows and energy transfer systems. However, for someone new to the world of data visualization, these graphs can initially seem daunting. This beginner’s guide aims to simplify everything you need to know about Sankey charts, so you can start utilizing them in your own work with confidence.
**What is a Sankey Chart?**
At its core, a Sankey chart is a type of flow diagram that illustrates the quantity of flow through a process. Often used to visualize energy flows, material transport, or work flows in a system, Sankey charts are particularly effective for depicting the efficiency of the process they represent. They consist of arrows that represent the “flow” of materials, energy, or work, whose sizes are proportional to the quantity of the flow they represent.
**Key Components of a Sankey Chart**
The basic building blocks of a Sankey chart include:
1. **Flow**: Arrows that represent the flow of energy, material, or information between processes.
2. **Activities**: Boxes that signify the processes, units, or elements that the flow is connected to.
3. **Inputs and Outputs**: The points at which the system starts and ends, typically at the edges of the chart.
4. **Flow Widths**: The width of the arrows, which is directly related to the quantity of the flow being represented.
**Understanding the Layout**
Sankey charts typically follow a specific layout with flow emanating from an input source, passing through different processes (nodes), and ultimately converging to an output or a loss:
1. **Inputs**: Material or energy enters the system from an outside source.
2. **Transformations**: Flow through various nodes that represent processes or units. The width of these arrows can reflect changes in the amount of flow as it travels along the path.
3. **Losses or Waste**: A significant segment of the flow will be directed to the output, denoted by narrow channels that represent inefficiencies, waste, or unrecoverable outputs like exhaust or waste material.
4. **Outputs**: The system releases the remaining flow as a valuable output, such as usable energy or final products.
**How to Read a Sankey Chart**
1. **Identify the Inputs and Outputs**: Determine where the energy or materials enter and leave the system.
2. **Assess Efficiency**: Compare the widths of the arrows to understand where the flow is concentrated. Wide arrows signify substantial flow, whereas narrow ones indicate losses or inefficiencies.
3. **Look for Patterns**: Sankey charts often reveal patterns that highlight opportunities for improvements in efficiency or waste reduction.
**Creating Sankey Charts**
Creating a Sankey chart might seem complex, but with the right tools, it’s quite straightforward. Many data visualization software applications offer Sankey chart options, allowing for ease of import and export of data, customization of the chart layout, and control over the visual design elements.
**Beginner Tips**
– **Start Simple**: Don’t overcomplicate your first attempt. Use a basic dataset with a flow that’s easy to understand.
– **Iterate**: If the first version of your Sankey chart isn’t delivering the most straightforward or informative presentation, don’t worry. The beauty of data visualization is in the iteration.
– **Consider the Audience**: Make sure your chart is not only informative but also engaging for your audience. Keep it as visually intuitive as possible.
Sankey charts can be an excellent tool for illustrating data-based insights, particularly for systems where energy or materials flow plays a significant role. By understanding the components and layout, beginners can apply Sankey diagramming to a variety of scenarios, making them a valuable asset to any data-driven professional’s toolkit.
