A Comparison of Radial and Linear Charts for Visualizing Daily Patterns

Area of Science:

• Human-Computer Interaction
• Data Visualization
• Traffic Safety

Background:

• Radial charts are often less effective than linear charts for data visualization.
• The suitability of radial charts for periodical time-dependent data, particularly daily patterns, remains debated.
• Existing research suggests radial chart drawbacks often outweigh their perceived benefits.

Purpose of the Study:

• To systematically evaluate the effectiveness of radial versus linear charts for visualizing daily traffic accident patterns.
• To compare accuracy, efficiency, and user preferences for different chart layouts and variants.
• To investigate if the cultural familiarity with radial clocks aids in daily pattern visualization.

Main Methods:

• A crowd-sourced experiment involving 92 non-expert users.
• Comparison of radial and linear charts, including juxtaposed 12-hour and single 24-hour variants.
• Evaluation across four low-level data tasks and one high-level interpretation task.

Main Results:

• The 24-hour linear bar chart demonstrated the highest accuracy and efficiency across all tasks.
• Users consistently preferred the linear bar chart over radial chart variants.
• Linear layouts proved more effective for visualizing periodical daily patterns.

Conclusions:

• Linear charts, specifically the elementary 24-hour bar chart, are the most effective for visualizing daily patterns.
• The findings provide strong evidence against the use of radial charts for daily pattern visualization, even with potential clock-reading familiarity.
• Future research should prioritize linear chart designs for time-dependent data analysis.