Understanding Sankey Charts: Visualizing Flow and Change in Your Data
Sankey diagrams are an invaluable tools for anyone seeking to comprehend complex data systems where the flow and transformation of energy or materials are prime concerns. These intuitive visual representations break down complex data flows into a more digestible format. By displaying information as flows between discrete processes or components, they offer deeper analytical insights into how systems operate.
### What are Sankey Charts?
Sankey charts are a type of flow diagram that illustrate the quantity or magnitude of flows within a process or system. Their distinctive feature is that the thickness of the arrows varies in proportion to the quantity of the flow they represent. This makes them particularly useful for large-scale processes where it is critical to understand the relative sizes of different flow channels, and how they contribute to or detract from the system as a whole.
### Key Characteristics of Sankey Diagrams
**1. Direction and Flow Representation:**
Sankey diagrams illustrate flow rates in both direction and magnitude. The direction is clear through the orientation of the arrows, and the flow size is conveyed by the arrow’s thickness.
**2. Process Connection:**
These diagrams connect different elements of a system through flows, depicting how elements relate to one another in terms of the transfer of resources, energy, or data.
**3. Proportional Width:**
The width of the connecting arrows is directly proportional to the volume, frequency, or speed of the flow being depicted. This means if one process is significantly larger or occurs more frequently than another, its arrow will be thicker.
### Uses of Sankey Diagrams
Sankey charts are used in a variety of fields to visualize data flows including:
– **Energy Efficiency and Sustainability:**
– Illustrating energy flow in buildings and cities.
– Analyzing the energy usage across different stages of manufacturing and supply chains.
– **Chemical Reactions and Processes:**
– Showing the flow of reactants, by-products, and energy in a chemical reaction.
– Mapping the steps involved in producing substances.
– **Financial Flows:**
– Visualizing cash flow within companies or the movement of funds across various markets.
– **Data Science and Big Data:**
– Tracking data packets as they traverse through the network nodes.
– Visualizing the flow of online information and interactions.
### How to Read a Sankey Chart
To effectively interpret a Sankey diagram:
– **Identify the Processes:**
Look at the nodes and label to identify each component of the flow.
– **Analyze the Flow Directions:**
Follow the direction of the arrows to see the path taken by the flow.
– **Assess the Flow Magnitudes:**
Notice the varying widths of the arrows to understand where the flow is greatest.
– **Look Out for the Accumulation Points:**
When flows come together in broader arrows, the processes they represent occur at a higher volume.
### Creating a Sankey Chart
When designing a Sankey diagram:
– **Start with Data Points:**
Gather the data that represents the flows you wish to visualize.
– **Identify Nodes and Arrows:**
Decide on the processes involved and create nodes; connect them with arrows to depict the flows.
– **Choose the Appropriate Scale:**
The scale should be such that the diagram’s readability does not suffer, but also conveys the most relevant information.
Sankey charts are powerful tools for understanding and communicating complex data flows. They simplify dense data into a more comprehensible and analytical format, allowing for swift identification of key flows and areas of interest. Whether it’s in energy systems, business analytics, or data science, the Sankey chart remains a vital tool to keep in your visual representation arsenal.
