// First root configured to use km
IAgStkObjectRoot root1 = new AgStkObjectRootClass();
root1.UnitPreferences.SetCurrentUnit("Distance", "km");

// Second root configured to use miles
IAgStkObjectRoot root2 = new AgStkObjectRootClass();
root2.Isolate();
root2.UnitPreferences.SetCurrentUnit("Distance", "mi");

// Create new scenario and ship object
// Close current scenario
if (root1.CurrentScenario != null)
{
    root1.CloseScenario();
}
root1.NewScenario("Test");
root1.CurrentScenario.Children.New(AgESTKObjectType.eShip, "Ship1");

// Obtain references to the ship object from each root
IAgShip shipFromRoot1 = root1.GetObjectFromPath("Ship/Ship1") as IAgShip;
IAgShip shipFromRoot2 = root2.GetObjectFromPath("Ship/Ship1") as IAgShip;

shipFromRoot1.SetRouteType(AgEVePropagatorType.ePropagatorGreatArc);

IAgVePropagatorGreatArc greatArcFromRoot1 = shipFromRoot1.Route as IAgVePropagatorGreatArc;
IAgVePropagatorGreatArc greatArcFromRoot2 = shipFromRoot2.Route as IAgVePropagatorGreatArc;

IAgVeWaypointsElement waypointsFromRoot1 = greatArcFromRoot1.Waypoints.Add();

waypointsFromRoot1.Altitude = 1; // 1 km

IAgVeWaypointsElement waypointsFromRoot2 = greatArcFromRoot2.Waypoints.Add();

waypointsFromRoot2.Altitude = 1; // 1 mile

greatArcFromRoot1.Propagate();

int i = 1;
foreach (IAgVeWaypointsElement wpt in greatArcFromRoot1.Waypoints)
{
    Console.WriteLine("Point #{0} Altitude {1} {2}", i, wpt.Altitude, root1.UnitPreferences.GetCurrentUnitAbbrv("Distance"));
    ++i;
}
Console.WriteLine();

//Sample Output
//Point #1 Altitude 1 km
//Point #2 Altitude 1.609344 km

i = 1;
foreach (IAgVeWaypointsElement wpt in greatArcFromRoot2.Waypoints)
{
    Console.WriteLine("Point #{0} Altitude {1} {2}", i, wpt.Altitude, root2.UnitPreferences.GetCurrentUnitAbbrv("Distance"));
    ++i;
}

//Sample Output
//Point #1 Altitude 0.621371192237334 mi
//Point #2 Altitude 1 mi

root1.CloseScenario();