pressureAltitude static method

double pressureAltitude({ required double airportElevation, required double airportAltimeter, LengthUnit unitElevation = LengthUnit.ft, PressureUnit unitAltimeter = PressureUnit.inHg, })

Calculate pressure altitude from airport elevation and QNH (airport altimeter).

airportElevation is the airport's elevation. Defaults to feet if no length unit is provided.

airportAltimeter is the airport's altimer setting (QNH). Defaults to inches Mercury (inHg) if no pressure unit is provided.

Implementation

static double pressureAltitude(
    {required double airportElevation,
    required double airportAltimeter,
    LengthUnit unitElevation = LengthUnit.ft,
    PressureUnit unitAltimeter = PressureUnit.inHg}) {
  // Ensure altitude is in feet (we will do internal calculation in feet).
  airportElevation = Convert.lengthToFeet(airportElevation, unitElevation);

  // Get standard SL pressure based on desired pressure unit, calculate
  // pressure altitude hp.
  var pressureSLStd = (unitAltimeter == PressureUnit.inHg)
      ? pressureSlStdDayInchesHg
      : pressureSlStdDayHectoPascal;
  var hp = airportElevation +
      pressureCalcConstant *
          (1 - pow((airportAltimeter / pressureSLStd), pressureCalcExponent));

  // If non-feet unit was requested, convert hp (currently in feet) back to
  // same unit elevation was provided in.
  return (unitElevation == LengthUnit.ft)
      ? hp
      : Convert.length(hp, LengthUnit.ft, unitElevation);
}