SUUNTO X-Lander - Manual (Page 42)

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6.5.2 Where do I find the correct declination for my area so I can
set my Wristop Computer?
Local declination, either E or W, is usually marked on maps with either one-degree or half-degree accuracy.
6.6 EFFECT OF AIR TEMPERATURE ON ALTITUDE
MEASUREMENT
The atmospheric pressure means the weight of air mass above the observer: at a higher altitude there is less
air than at a lower altitude. The principle of an altimeter is to measure the different air pressure between
different altitudes.
The air weight is affected by the outside temperature. Consequently the air pressure difference between two
altitudes is also dependant on temperature.
The altitude calculation of Wristop Computer is based on the air pressure at certain normal temperatures. Each
altitude has a definitive normal temperature. The normal temperatures at each altitude are presented in table 1.
Altitude (m) Altitude (ft) Temperature (C) Temperature (F)
above sea level above sea level
0 0 15.0 59.0
200 656 13.7 56.7
400 1312 12.4 54.3
600 1969 11.1 52.0
800 2625 9.8 49.6
1000 3281 8.5 47.3
1200 3937 7.2 45.0
1400 4593 5.9 42.6
1600 5250 4.6 40.3