Sankey charts are a powerful and increasingly popular way to visualize data, particularly when it comes to understanding flows, processes, or relationships within a system. Despite their utility, it’s not always immediately clear how to read or create a Sankey diagram. This beginners’ guide aims to demystify the Sankey chart, helping you understand the intricate mechanics behind this type of visualization, and how to effectively use it in your work.
### What is a Sankey Chart?
Imagine a pipeline that takes a resource from an input and diverts it through various processes before reaching an output. Now imagine each pipeline can vary in width based on the volume of flow. This is essentially a Sankey chart. Each “pipe” in the chart represents a flow or a process, with its width corresponding to the quantity or rate of this flow.
### Key Components of a Sankey Chart
**1. Pumps & Valves:** These represent the points in a system where the flow originates or stops, typically denoted by “pumps” at the source and “valves” at the destination.
**2. Pipes:** The actual flow paths that lead from input to output. Thinner pipes indicate a smaller flow, and wider pipes denote a larger flow of resource.
**3. Nodes:** Intersections where two or more pipes meet, indicating where a flow splits or gets combined.
**4. Labels:** Information about the processes or systems the flow represents, as well as the total amount of input or output.
### How to Read a Sankey Chart
Sankey charts are read by observing the widths of the flow paths. Here’s a simple way to interpret them:
– **Width:** A wide pipe indicates a higher relative flow.
– **Length:** The longer the path, the more complex the conversion of the resource.
– **Concentration:** The closer together the pipes are, the greater the conversion of one part to another without actual movement (e.g., energy conversion loss).
### Creating Your Own Sankey Chart
Sankey charts are generally created using specialized software, such as MS Excel, Google Sheets, Tableau, or dedicated Sankey chart software. The process usually involves:
1. **Determining Your Input and Output:** Understand the system for which you are creating the Sankey diagram and identify the input and output to be analyzed.
2. **Establishing Steps:** List all the intermediate steps or processes the flow goes through.
3. **Quantifying Flow:** Measure the amount of flow at each step in your process.
4. **Creating the Chart:** Enter your data into the chosen platform, following the specific steps and guidelines for creating Sankey diagrams.
### Use Cases for Sankey Charts
Sankey charts are used in a wide variety of fields, including:
– **Energy Analysis:** Visualizing energy use and conversion from one form to another.
– **Water Flows:** Monitoring the movement of water through a network of water systems.
– **Financial Flows:** Showing money being spent and its redistribution in various areas.
– **Data Analysis:** Representing the flow of data between different components in a computer system.
### Conclusion
Understanding and using Sankey charts can provide significant insights into the flows and interactions within complex processes. By visually representing the direction and magnitude of flows, these charts can simplify the analysis of massive and intricate systems. Whether a data analyst, engineer, or business professional, gaining competence with Sankey charts will enhance your ability to communicate complex information effectively.
