Data Analytics: Foundations to Practice · Data Visualization Principles
Choosing the Right Chart Type
Each chart type is genuinely well suited to a specific kind of comparison, and forcing the wrong data into the wrong chart type either obscures a real pattern or, worse, suggests a pattern that isn't actually there.
A line chart connects data points across a continuous sequence, most commonly time, making it the natural choice for showing a genuine trend, such as monthly revenue over the past two years; the connecting line itself visually implies continuity between the plotted points, which is exactly why a line chart is a poor, misleading choice for categories that have no genuine inherent order or continuous relationship between them.
Key Takeaways
- Line charts suit trends over a continuous sequence like time; the connecting line implies continuity, making it a poor choice for unordered categories.
- Bar charts compare discrete categories using length, one of the most accurately perceived visual attributes, which is why their axis should start at zero.
- Scatter plots place two continuous variables on separate axes, making them the natural choice for examining a relationship between two variables.
- Pie charts are appropriate only for a small number of categories with visibly distinct proportions, since angle and area comparison is less accurate than length or position.