The basic structure of the RadGauge, regardless of its type consists of a Scale. The scale contains the Major and Minor Ticks that mark the values, along with the Labels for them. In the scale the developer can define separate Ranges in order to colorize them differently.
RadCircularGauge Controls have value that is visually represented by the filler of the Scale.
RadRadialGauge Controls expose a Pointer that shows the value on the scale. The Pointer has a Cap (Radial) or Track (Linear) that allow for customizing its appearance.
The sections and images below show these elements on simple gauges for visual clarity.