Bubble Charts are usually used when our data contains points with more than two parameters and you can put more attention to some specific values in your chart by different bubble sizes. They are quite popular in presenting financial data, as these charts allow four different variables to be plotted within the same graph.
This Chart represents the training statistics for the best four sportsmen: Christopher Sanchez, Judy Evans, Walter Burke and Daniel Williamson. Each bubble stands for one training; the bubble size means its duration, the pulse and power values are placed along the axes. Tooltips are enabled and they display all parameters: date, power, pulse and the training duration are shown in the tooltip body; each tooltip’s title contains the sportsman’s name. Grid is also enabled and the bubbles are translucent, so the grid is seen through the bubbles and helps to watch the values. The x-axis (values of average power) range is from 125 to 200, the y-axis (values of average pulse) range is from 40 to 160. This is made to zoom the chart and to get rid of empty place, as all values are focused in this range.
You can also manage the chart behavior by clicking or hovering the legend: when you hover a legend item, its series becomes highlighted, and you can select a series by clicking its legend items.