Magnetic Variation

Use the magnetic variation (more properly, the "magnetic declination") API to find the offset of magnetic north from true north at a given latitude and longitude within the simulator.

In the real world, the Earth's magnetic field is irregular, such that true north (the direction along a meridian toward the north pole) does not necessarily match what a magnetic compass shows as north.

Using this API ensures that you present the same offsets to users as X-Plane's built-in instruments.

XPLMGetMagneticVariation

function

Returns X-Plane's simulated magnetic variation (declination) at the indication latitude and longitude.

XPLM_API float      XPLMGetMagneticVariation(
                         double               latitude,
                         double               longitude
                    );

XPLMDegTrueToDegMagnetic

function

Converts a heading in degrees relative to true north into a value relative to magnetic north at the user's current location.

XPLM_API float      XPLMDegTrueToDegMagnetic(
                         float                headingDegreesTrue
                    );

XPLMDegMagneticToDegTrue

function

Converts a heading in degrees relative to magnetic north at the user's current location into a value relative to true north.

XPLM_API float      XPLMDegMagneticToDegTrue(
                         float                headingDegreesMagnetic
                    );