What's the meaning of PxVehicleWheel/DriveGraphChannel ?

in func processSuspTireWheels which is called in updateDrive4W.
what’s the use of GraphData which is defined in PxVehicleUtilTelemetry.h
and how it affects the computation of force/torque?

void processSuspTireWheels
(const PxU32 startWheelIndex, 
 const ProcessSuspWheelTireConstData& constData, const ProcessSuspWheelTireInputData& inputData, 
 ProcessSuspWheelTireOutputData& outputData)
{
...
	zeroGraphDataWheels(startWheelIndex,PxVehicleWheelGraphChannel::eJOUNCE);
	zeroGraphDataWheels(startWheelIndex,PxVehicleWheelGraphChannel::eSUSPFORCE);
	zeroGraphDataWheels(startWheelIndex,PxVehicleWheelGraphChannel::eTIRELOAD);
	zeroGraphDataWheels(startWheelIndex,PxVehicleWheelGraphChannel::eNORMALIZED_TIRELOAD);
	zeroGraphDataWheels(startWheelIndex,PxVehicleWheelGraphChannel::eNORM_TIRE_LONG_FORCE);
	zeroGraphDataWheels(startWheelIndex,PxVehicleWheelGraphChannel::eNORM_TIRE_LAT_FORCE);
	zeroGraphDataWheels(startWheelIndex,PxVehicleWheelGraphChannel::eTIRE_LONG_SLIP);
	zeroGraphDataWheels(startWheelIndex,PxVehicleWheelGraphChannel::eTIRE_LAT_SLIP);
	zeroGraphDataWheels(startWheelIndex,PxVehicleWheelGraphChannel::eTIRE_FRICTION);
...
}

The graph data is purely a telemetry recording system. The telemetry system collects data from the engine, suspensions, tires and wheels so that they may be visualised or written to file or whatever the user decides to do with the data.

Telemetry data is recorded only if updateSingleVehicleAndStoreTelemetryData is called instead of updateVehicles. It does not affect the behaviour of the affected vehicle or any other.

An example of telemetry visualisation can be seen in SampleVehicle.

Thanks