Altimeter X vs A

iOS/GPS altitude Altitude estimated by the device's location service. It works reasonably well in most situations but can't track small changes and can be unreliable indoor. Barometric altitude (iPhone 6 minimum) Altitude based on the device's barometer. This is how most hardware altimeters work. It can track very small relative variations but must be calibrated with weather data or GPS. Calibration with weather data grabs current sea-level pressure and temperature at your location from a nearby weather station. GPS calibration takes the current iOS/GPS altitude as a starting point then uses the barometer to track changes. Elevation database This method displays earth surface elevation at your location by polling an elevation database. It works even with very imprecise location data but requires network access. Surface elevation usually includes buildings and trees.

A-EFIS is an Electronic Flight Information System for airplanes, which runs right on your iPhone/iPad. A-EFIS works perfectly with the internal sensors of your iPhone/iPad A-EFIS makes use of digital filtering methods and state-of-the-art stochastic models in order to achieve exceptional accuracy and robustness. ATTENTION: A-EFIS ONLY WORKS ON AIRPLANES. NOT TO BE USED IN HELICOPTERS OR LAND VEHICLES BECAUSE INDICATIONS WILL NOT BE CORRECT. USE ONLY IN AN AIRPLANE! Features: - Artificial Horizon (AHRS) - Ground speed (via GPS) - Altimeter (via GPS) - Vertical speed (via GPS) - Turn coordinator - Slip ball - Compass - True course indicator (via GPS) - Deviation from true track indication A-EFIS can also be used with the X-Plane flight simulator. A-EFIS has been extensively tested on ultralights, LSA, general aviation and even airliners. IMPORTANT NOTICE: A-EFIS is not a certified aviation instrument. Do not rely on A-EFIS as your only navigation aid. Failure to comply to this warning may result in property damage, serious injury or death. You assume total responsibility and risk associated with using this application.