Which visualization technique is typically not used for time-series analysis?

A radar chart, also known as a spider chart or web chart, is primarily designed to display multivariate data in a way that makes comparisons across different variables easier. It represents different variables on axes that start from the same central point, highlighting relative values for those variables. This format is quite effective for assessing performance or understanding relationships among variables in a radial layout, but it does not effectively convey information over time.

Time-series analysis focuses on data points collected or recorded at specific time intervals to identify trends, patterns, and changes over time. Techniques commonly used in time-series analysis, such as line graphs, bar charts, and stacked area charts, are directly suited to showcasing how data trends evolve, facilitating the analysis of temporal patterns. In contrast, the structure of radar charts makes it challenging to illustrate changes over time accurately, hence its unfitness for time-series analysis.