Designing Charts: Determining Axis Ranges

Axis ranges are crucial in making your charts easy to understand and interpret. Let’s imagine you’re creating a chart to show the monthly sales figures of a small store for a year. Here’s my step-by-step guide to setting axis ranges:

  1. Understand your data: Look at your dataset and identify the minimum and maximum values. In our example, say the lowest monthly sales are $1,500 and the highest are $5,000. 
  2. Define your axis range: Once you have the minimum and maximum values, decide on the range for your x and y axes. For the x-axis, which represents time, we can divide it evenly into monthly segments. For the y-axis, which represents sales, we might want to choose a range that starts at $1,000 and goes up to $6,000. In this case, we would not start the Y-axis at zero because we don’t have any observations close to Zero, so we instead opt for a range that gives us some buffer above and below are actual data points.
  3. Choose an appropriate scale: The scale of your range will determine how data points are plotted along the axis. Since our y-axis range is from $1,000 to $6,000, we could choose a scale of $500 or $1,000 increments to create easy-to-read intervals. For the x-axis, a monthly scale would be appropriate for our data. 
  4. Use helpful labels: Don’t forget to label your axes so that viewers can understand the values represented at each tick. In our example, the y-axis could be labeled ” Sales ($),” and the x-axis could be labeled ” Months.” 
  5. Assess and adjust: After plotting your data points, you may need to reassess your axis ranges and scale to ensure the chart effectively presents the information. If the data is too cramped or the scale isn’t easy to read, tweak the axis ranges and scale until you find the optimal setting for your chart.

 

The goal is to create a chart that tells a clear and engaging story, so always prioritize the clarity and readability of your visuals.