MeccaMeter calculates the iPhone position anywhere in the world to the nearest ten meters. Primarily it uses GPS, but if this fails it resorts to cellular and finally wi-fi. It then uses an algorithm to calculate the shortest great circle distance from the device position to Kaabah. It then calculates the heading based on the initial track of the great circle route
The user is presented with a compass with a needle overlay. The green end of the arrow points towards Mecca. The user then rotates the device until the device points in the same direction as the heading to Mecca. When established on the heading the device vibrates.
The heading is based on the inital track of the great circle route from the device position to Mecca. The great circle route is the shortest distance across the surface of the earth between two points. This can be up to 90 degrees different from Rhumb lines which are a line of constant track between two points.
iSpi is the app that identifies major landmarks in the top tourist destination cities in the world. Find a viewpoint with an unobstructed view of all the major landmarks. Open iSpi and select the city you are in. Then pan the device across the horizon and it will pick out major landmarks in the area and give a readout of the distance to the landmark.
Aircraft turbulence is categorised as either light, moderate or severe. Air traffic controllers routinely ask pilots to report the level of turbulence that the aircraft is experiencing. These reports are called ride reports. Ride reports are used by other aircraft to decide which route and altitude to take to avoid the turbulence. These reports are necessary for both passenger comfort and safety. Some airlines require their pilots to report flight in severe turbulence to the airline engineering department as an aircraft engineering inspection may be required. Pilot assessment of turbulence levels are both subjective and inaccurate.
The International Civil Aviation Authority (ICAO) category definitions for turbulence are:
1.1g < Light < 1.3g
1.3g < Moderate < 1.5g
1.5g < Severe
Ride Reporter continually measures the acceleration that the device is experiencing. The device can be used in any orientation as it takes input from the three accelerometers on the device. The instantaneous g reading is displayed on a scale with a needle. Ride Reporter continually records the highest g reading within the last five seconds and gives a text readout based on the reading.