How to Create and Use Sankey Charts for Data Visualization

Understanding the Basics of Sankey Charts

Selecting the Right Tools

Several tools, such as D3.js, Google Sheets, and Tableau can help you create Sankey charts. For those who don’t have access to software like Tableau, libraries such as D3.js and plotly.js are available to get the job done.

// Sample D3.js Sankey Chart code snippet goes here

        

Creating a Sankey Chart

Below is a step-by-step guide to making a basic Sankey chart using plotly.js, which requires minimal setup.

1. Install JavaScript libraries:

   
   npm install plotly.js
   
                   

2. Create a data structure that holds the Sankey chart values:

   
   const data = [
       {
           "z": [0, 4, 9, 14, 19, 24],
           "type": "sankey",
           "orientation": "h",
           "valueformat": ",r",
           "link": [
               // Define link between nodes
           ],
           "node": [
               // Define nodes
           ],
           "colorway": [
               "rgb(31, 120, 190)",
               "rgb(255, 119, 0)",
               "rgb(44, 160, 44)",
               "rgb(214, 39, 40)",
               "rgb(148, 103, 189)",
               "rgb(215, 48, 39)",
               "rgb(77, 175, 74)",
               "rgb(166, 206, 227)",
               "rgb(31, 167, 231)",
               "rgb(250, 177, 160)",
               "rgb(253, 190, 212)",
               "rgb(255, 127, 0)",
               "rgb(178, 223, 138)",
               "rgb(190, 134, 151)",
               "rgb(247, 177, 174)",
               "rgb(188, 189, 235)",
               "rgb(105, 148, 212)"
           ]
       }
   ];
   
                   

3. Initialize the Sankey chart:

   
   Plotly.newPlot('sankeyDiv', data, {width: 800, height: 600});
   
                   

Interpreting Sankey Charts

Interpreting a Sankey chart involves viewing the flow from left to right. Each horizontal line represents the flow of material, energy, or money. The width of each line represents the magnitude of the flow. This format helps make comparisons between flows intuitive.

Using Colors and Labels

Differentiate your flows with a range of color choices and use clear, descriptive labels for your nodes (entry points and exit points) and links (the flows themselves). This will make your chart more readable and informative.

Closing Thoughts

Sankey charts can offer clear insights into resource allocation and process flow. With the tools and techniques outlined in this article, you can start crafting and using Sankey charts to bring clarity to your data visualization needs.