Common Chart Design Pitfalls: Diagonal Text

The issue of text orientation in data visualization is an essential aspect worth considering to ensure that the audience can easily and quickly understand the presented information. Diagonal text may impact reading speed as our brains are hardwired to recognize and process horizontal and vertical text more efficiently. The diagonal text requires slightly more cognitive effort and may slow down the reading process, especially when dealing with a lot of data. 

Here are some suggestions to address this challenge and optimize your data visuals. 

1. Horizontal Text – Wherever possible, try to adjust the text to be horizontal. This is the most natural alignment for reading and allows users to process the information quickly. 
2. Vertical Text – If you cannot keep the text horizontal due to space constraints or stylistic choices, consider using vertical text instead of diagonal. Vertical orientation is still faster to read than diagonal text, although not as efficient as horizontal text.
3. Limited Use of Diagonal Text – In certain scenarios, such as a scatter plot where the data points are closely packed, you might still need to use diagonal text to avoid overlap or clutter. In these situations, use diagonal text only for critical labels.
4. Abbreviations and Acronyms – You can use abbreviations and acronyms for long labels and ensure they are widely understood by your audience.
5. Legibility – Ensure that the font size, style, and color are legible regardless of the text’s orientation.
   Example: Choose a simple sans-serif font, such as Arial or Helvetica, with a contrasting color from the background, and ensure the font size is large enough to be comfortably read by the audience.