The bubble chart
The bubble series is an extension of the scatter series where each individual data point has a variable size. It is generally used for showing 3-dimensional data on a 2-dimensional chart, and the bubble size reflects the scale between z-values.
Understanding how the bubble size is determined
In Highcharts, bubble size is decided by associating the smallest z-value to the plotOptions.bubble.minSize
option and the largest z-value to plotOptions.bubble.maxSize
. By default, minSize
is set to 8 pixels in diameter, whereas maxSize
is set to 20 percent of the plot area size, which is the minimum value of width and height.
There is another option, sizeBy
, which also affects the bubble size. The sizeBy
option accepts string values: 'width'
or 'area'
. The width value means that the bubble width is decided by its z-value ratio in the series, in proportion to the minSize
and maxSize
range. As for 'area'
, the size of the bubble is scaled by taking the square root of the z-value ratio (see...