Welcome to Stockholm Arlanda Airport. Swedens largest airport with almost 17 million passengers and around 190.000 start and landings yearly.
IATA code: ARN
ICAO code: Essa
Now to the coordinates:
Arlanda have three start and landing runways namned 1, 2 and 3. But they are also named something else, in what direction they are.
If you look at the runway directions you will get four different numbers, lets name them 0AA, 0BB, CCC and DDD.
Let AA be the lowest number and DDD the biggest.
The height of the Air Traffic Control Tower gives you EE
The Math:
For north 59° 38.xxx
xxx=DDD*3+CCC+24
And east 017° 56.yyy
yyy=BB*4+EE*6
