G L O S S A R Y
G L O S S A R Y
ALTIMETER
Indication of altitude in relation to sea level
Description of the function
In ALTIMETER mode, your watch is transformed into a barometric altimeter and displays the altitude in relation to the average sea level.
20Explanations
As this instrument is barometric, it calculates the altitude according to atmospheric pressure.
As altitude increases, pressure decreases and vice versa. Therefore, the altimeter measures the difference in pressure and displays the altitude. It is therefore an ideal instrument for measuring ascents. (e. g. when hiking in the mountains).
2000m
1500m
1000m
500m
0m | P = pressure |
Note: "Calibrating" an altimeter means setting it to the actual altitude of a known point (see the setting procedure on page 14).
The values of actual altitudes can be found from various sources: signs, contour lines and benchmarks on maps.
540 m
Miscellaneous information | 540 m |
Your watch compensates for temperature.
The altitude displayed is therefore corrected automatically. The altimeter makes a measurement every 10 seconds.
Your altimeter will not show the variations in altitude in an aircraft as the cabin is pressurised (constant pressure).
Unit conversion: 1 metre [m] | = | 3.281 feet [ft] |
1 foot [ft] | = | 0.305 metres [m] |
Average pressure, at sea level: 1013.25 hPa
780 m
21
Warning!
As pressure is used to calculate the altitude, the altimeter is sensitive to variations in atmospheric pressure as the weather changes. It is not uncommon to see differences in altitude of 100 m in one night.
The value displayed may vary without your altitude actually changing.
Change in weather = variation in pressure = modification of altitude displayed
540 m | 540 m |
Thus it is necessary to "calibrate" the altimeter as often as possible.
Average variation in pressure and temperature depending on altitude:
Altitude [m] / [ft] | Pressure [hPa] | Temperature [˚C]/[˚F] | ||
| 0 | 1013.25 | 20 | / 68 |
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111 | / 364 | 1000 | 19.3 | / 66.7 |
988 / 3242 | 900 | 13.6 | / 56.4 | |
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1949 | / 6395 | 800 | 7.3 / 45.2 | |
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Technical data
Measuring range: | - 400 m to +9000 m | - 1300 ft to +29500 ft |
Resolution: | 1 m | 3 ft |