# A Comparison of Radial and Linear Charts for Visualizing Daily Pattern

## TL;DR

This study systematically compares radial and linear charts for visualizing daily patterns, finding that linear charts outperform radial ones in accuracy, efficiency, and user preference across multiple tasks.

## Contribution

It provides empirical evidence that linear charts are more effective than radial charts for visualizing daily patterns, challenging the assumption that radial charts are naturally suited for periodical data.

## Key findings

- Linear charts are more accurate for daily pattern visualization.
- Linear charts are more efficient in task completion.
- Users prefer linear charts over radial charts.

## Abstract

Radial charts are generally considered less effective than linear charts. Perhaps the only exception is in visualizing periodical time-dependent data, which is believed to be naturally supported by the radial layout. It has been demonstrated that the drawbacks of radial charts outweigh the benefits of this natural mapping. Visualization of daily patterns, as a special case, has not been systematically evaluated using radial charts. In contrast to yearly or weekly recurrent trends, the analysis of daily patterns on a radial chart may benefit from our trained skill on reading radial clocks that are ubiquitous in our culture. In a crowd-sourced experiment with 92 non-expert users, we evaluated the accuracy, efficiency, and subjective ratings of radial and linear charts for visualizing daily traffic accident patterns. We systematically compared juxtaposed 12-hours variants and single 24-hours variants for both layouts in four low-level tasks and one high-level interpretation task. Our results show that over all tasks, the most elementary 24-hours linear bar chart is most accurate and efficient and is also preferred by the users. This provides strong evidence for the use of linear layouts - even for visualizing periodical daily patterns.