Calculation of Distance

Whether you are in the UK or USA a mile is a mile right? If I calculate the distance from Birmingham airport EGBB to say Gatwick EGKK as the crow flies it shows 112 miles. If I set a direct flight from these 2 airports in IF it shows 97 miles. It would appear that the distance calculator in IF is incorrect. I have thought this for some time. Can anyone else validate my findings? From my Caldwell IF us displaying nautical miles and not miles as normally perceived. Just checking my assumptions.


According to the devs, the regions are actually slightly smaller in IF than real life. On the complete global map, you will probably find a discrepancy in distances.

There are two ‘miles’. The nautical mile and the land-mile. Nautical one is 1.852m, land is 1.600m. So, nautical is 1.1575 times land mile.
In aviation you always calculate in knots and therefor in nautical Miles.


Yup it shows mm in display when selected. Cartesian cords should be the same assuming model of the earth is exact. Thx. Brain now in gear.

You mean km (kilometres) and not m (metres)

It is in nautical miles. Calculated by the great circle formula:

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That makes more sense. Otherwise I would’ve thought they did it on purpose because of plane/airport size