public double Aspect {get;}

{
  // Note: Needs QueuedTask to run
  {
    // get elevation, slope and aspect values
    SurfaceValues values = tinLayer.GetSurfaceValues(mapPoint);
    var elev = values.Elevation;
    var slopeRadians = values.Slope;
    var slopeDegrees = values.SlopeDegrees;
    var slopePercent = values.SlopePercent;
    var aspectRadians = values.Aspect;
    var aspectDegrees = values.AspectDegrees;
  }
}