The example uses a GradientControl, part of Google Maps API for Flash Utility Library
. The map visualizes a dataset of per capita greenhouse gas emissions for each country, with values between 0 and 55. The gradient bar illustrates what the gradients are set to - green to yellow for values between 0 and 10, yellow to orange for values between 10 and 20, orange to red for >20. You can use sliders to change the positions of the gradient borders 10 and 20, as well as click on any country and use a different slider to change the associated value. Due to the use of encoded polylines, the changes are quick enough to happen in realtime.
The source code for this example is in GradientControlExample.mxml.
See the full documentation to learn how to use GradientControls.