A Bubble chart combines two series to draw a plot chart with varying point sizes. The encoding method for the size of the bubbles, as well as their minimum and maximum size can be specified.
Use the EncodingMethod property to set whether to size the bubbles according to diameter or area. When specifying the size of the bubble, both the diameter and area are measured as a percentage of the total diameter or area of the PlotArea. Inverting these values (making the Minimum value larger than the Maximum) draws large bubbles for small values, and small bubbles for large values.
The EncodingMethod is a property of the Bubble object and can be accessed through the Bubble node in the ChartGroupsCollection Editor.
The maximum and minimum allowable size for bubbles can be set using the MaximumSize and MinimumSize properties respectively. These are properties of the Bubble object and can be accessed through the Bubble node in the ChartGroups Collection Editor as well.