XPLM_API void       XPLMWorldToLocal(
                         double               inLatitude,
                         double               inLongitude,
                         double               inAltitude,
                         double *             outX,
                         double *             outY,
                         double *             outZ);

This routine translates coordinates from latitude, longitude, and altitude to local scene coordinates. Latitude and longitude are in decimal degrees, and altitude is in meters MSL (mean sea level). The XYZ coordinates are in meters in the local OpenGL coordinate system.