The Drilldown Pie Chart Viewlet
The Drilldown Pie Chart Viewlet gives the user a standard pie chart display, with the added benefit and functionality of multiple levels of data. Double-clicking on a single section of the pie chart will "drill down" to a separate pie chart nested within the larger section above it. In the example below, a typical hierarchy of states and cities is shown. This viewlet makes multi-tiered comparisons of energy usage simple and concise.