Unraveling the Complexities of Data Flow: The Practical Guide to Creating Compelling Sankey Charts
Sankey charts (also called Sankey diagrams) are unique in their capability to visually describe data flow, not just individual components or data points, but the complex movement and transformation of data through various stages or systems. They are particularly valuable tools for data specialists looking to explain intricate data pathways, from supply chain operations to electricity consumption in large industries, or financial transactions. But with their intricate layout and layers of information, creating compelling and easy-to-understand Sankey charts can be complex. In this practical guide, we will unpack the complexities involved in generating these charts, providing you with the tools to create accurate and visually appealing Sankey diagrams.
Understanding the Basics
At the core of a Sankey chart’s purpose is its design: a visual representation that utilizes arrows or bands to depict the flow of data. The width of the arrows or bands directly corresponds to the volume or value of the data being depicted, making it an excellent tool for recognizing the balance and dynamics between data segments.
A Sankey chart typically consists of three key components:
1. **Source, Path, and Destination Nodes**: Representing the start, journey, and end of the data flow, respectively. These nodes could represent different entities like sectors, geographical locations, or different categories of data.
2. **Flow Arrows or Bands**: Indicate where data starts (source), where it goes (destination), and how much is moved along each path. These visually demonstrate the quantity of data crossing from one node to another.
3. **Color Coding**: Often used to highlight different categories within the same data system, enhancing the readability and interpretability of the chart.
The Art of Creating Compelling Sankey Charts
1. **Data Preparation**: Before creating the chart, perform thorough data cleaning to ensure accuracy. Identify the essential data elements and the flow patterns within your dataset.
2. **Selecting a Platform**: Several data visualization tools offer the capability to create Sankey charts, including Microsoft Power BI, Tableau, Python libraries such as Plotly or Bokeh, and R libraries like ‘santech’. Choose a tool based on accessibility, availability of features, and familiarity with the platform.
– **Microsoft Power BI**: Easy to use, with direct integration into office tools.
– **Tableau**: Offers extensive customization and deep integration with various data sources.
– **Python and Bokeh/Sankey library**: For users preferring programming languages, these offer the flexibility to tailor every aspect of the chart.
– **R and sankey library**: Another programming option, great for statistical analysis and detailed data manipulation.
3. **Descriptive Layout**: Organize the data flow logically. Typically, sources should be on the left, destinations on the right, with pathways connecting these nodes. Group similar flows together if needed, and ensure a clear and balanced layout to facilitate ease of understanding.
4. **Color Usage**: Choose colors that effectively differentiate segments without overwhelming the chart. The use of color coding should align with data categories, and ensure that your color schemes are accessible and visually appealing to your intended audience.
5. **Adding Annotations**: Include labels to identify source, path, and destination nodes. Additionally, annotate the major movements or key data points. This not only adds to the clarity of data flow but also serves as guidance for first-time viewers of the chart.
6. **Review and Iterate**: After creating the initial Sankey chart, review it for clarity and accuracy. Check if all data elements are clearly visible and if any further annotations would benefit understanding. Don’t hesitate to rework parts of the chart to enhance its comprehensibility and impact.
7. **Accessibility and Legibility**: Ensure your Sankey chart is accessible to all viewers, regardless of their level of expertise. This includes appropriate text sizes, clear labeling, and, where necessary, accessible color schemes for visually impaired viewers.
8. **Storytelling**: Finally, leverage the chart to tell a story about the data flow. This isn’t just about visually presenting information, but about informing and guiding the audience to understand the significance of the data patterns and their implications.
Creating compelling Sankey charts requires a balance between artistic design and data accuracy. By understanding the basics of Sankey charts and following the outlined steps, you can develop visual tools that effectively communicate complex data flows and enhance decision-making processes in your industry.
