Sankey charts, often known for their distinctive shape and the elegance with which they depict energy or material flows, are a powerful tool for visual analysis of networks involving a series of transfers or exchanges. In essence, they are flow diagrams that clearly represent the quantity of material, energy, or cost being transferred between different parts of a process. Whether you’re analyzing resource consumption in an industrial setting, energy distribution, or financial expenditure, Sankey charts can help you get a holistic understanding of how resources flow through a system and highlight bottlenecks, inefficiencies, and points of high concentration. Let’s dive into the basics to get a grasp on these intriguing charts.
**What are Sankey Charts?**
Sankey charts are named after Evelyn Brinton Sankey, who, in the 19th century, was the first person to popularize the use of these diagrams in an industrial context. They are especially useful in situations where the flow and distribution of things (like water, electricity, or money) are essential for identifying patterns and optimizing processes.
**Key Characteristics of Sankey Charts:**
– **Flow Direction:** Sankey charts display flows in one direction, from source to sink. The key to the diagram specifies each type of flow within the system.
– **Width of the Arrows:** The width of the arrows represents the magnitude of the flow quantity or intensity. Broad arrows show large flows, while thinner ones represent smaller ones.
– **Nodes:** The nodes are the points in the system at which flows enter or exit. They represent the entities that transfer the flow (such as processes, components, or products).
– **Efficiency:** Sankey charts often contrast different processes’ efficiencies by displaying the flow of energy or materials into and out of the system. The more of a flow that is lost as waste or heat, the thinner the corresponding arrow becomes towards the sink.
**Types of Sankey Charts:**
1. **Energy Sankey Charts:** These illustrate the conversion and distribution of energy within a physical system.
2. **Material Sankey Charts:** They depict the flow, conversion, and accumulation of materials in processes or networks.
3. **Financial Sankey Charts:** They are used to visualize the movements of money through different parts of a business or an economy.
**Creating a Sankey Chart:**
Building a Sankey chart involves several steps:
1. **Define the System:** Identify all resources, processes, and outputs in the system.
2. **Identify Flows:** Establish the direction and magnitude of each flow.
3. **Chart the Nodes:** Plot the nodes on the chart to represent points in the system.
4. **Layout the Arrows:** Connect the nodes with arrows, using widths to represent the flow sizes.
5. **Format the Chart:** Add labels, a legend, and any other information needed to interpret the chart effectively.
**Practical Applications:**
Sankey charts find application in a wide variety of situations, including energy optimization in buildings, production and supply chain analysis, waste management, and in finance for understanding the flow of money within an organization.
**Why Use Sankey Charts?**
Sankey charts offer several advantages:
– **Clear Visualization:** They distill complex flow data into a simple visual form that is straightforward to interpret.
– **Focus on Hot Spots:** By highlighting the width and direction of the flows, Sankey charts allow for an easy identification of areas that consume or generate more of a resource.
– **Comparative Analysis:** You can quickly compare alternative methods or changes within a process by comparing the width and shape of the arrows.
As you delve into the world of network analysis, incorporating Sankey charts into your toolkit can provide a greater insight into the complex interplay of flows and inventories within your systems. They offer a compelling method for storytelling with data – providing a clear, compelling illustration of how your resources are being utilized and where improvements might be made.
