The function of an altimeter is simple: It measures the altitude of an object above any fixed level, with sea level being the most common point of reference. It is used in a number of activities, from extreme sports like skydiving, to ground-based activities like hiking, climbing, and skiing, but its most prominent usage has always been tied to flight. As many watch enthusiasts are aware, the history of aviation and horology have long been linked through the necessity of a pilot needing to know the time immediately while in the air. Through this, the pilot?s watch has developed over the decades to become the recognizable icon it is today. The flieger triangle at 12 o?clock, the oversized case and crown, and the development of lume have all been tied to catering to a pilot?s needs while in flight so it was only a matter of time before watch brands embraced the altimeter. Here are five brands that have done just that over the past few years.  Oris Big Crown ProPilot Altimeter
In 2014, Oris tapped its flight heritage to release the Big Crown ProPilot Altimeter. The watch has two crowns: the crown at 2 o?clock adjusts time and date, while the crown at 4 o?clock operates the altimeter. To activate the altimeter, you must unscrew the second crown into position one, indicated by a red ring. At position 2, the altimeter can be set. Once this is completed, the watch illustrates the altitude through the yellow indicator and the air pressure via the red indicator. The altitude scale ...