When analyzing seasonal sales, which chart type is NOT recommended for effective trend visualization?

In the context of visualizing seasonal sales data, certain chart types are better suited for depicting trends over time compared to others. The pie chart, while effective for showing proportions at a single point in time, does not convey trends or changes over a period. Seasonal sales analysis requires the viewer to understand how sales fluctuate in different seasons, which involves a temporal aspect that pie charts cannot provide.

Time series charts, on the other hand, are specifically designed to display data points at successive intervals, making them perfect for revealing trends across time. Waterfall charts illustrate the cumulative impact of sequentially introduced values, and while they are not the first choice for trend analysis, they still offer some insight into changes over set periods. Heat maps can effectively show sales performance across different seasons and time periods, enabling quick visual assessment of performance variance across months or quarters.

Choosing a pie chart for seasonal trend analysis would limit the viewer's ability to grasp the dynamics of sales fluctuations, rendering it ineffective in this specific context.