Adventure Cycling Association Forum

Bicycle Travel => General Discussion => Topic started by: crashmbro on August 18, 2017, 08:59:45 pm

 
Title: Altimeter
Post by: crashmbro on August 18, 2017, 08:59:45 pm
Has anyone had a favourable experience with altimeter apps for an iPhone? I need to measure height above sea level accurately.


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Title: Re: Altimeter
Post by: John Nelson on August 18, 2017, 11:06:39 pm
Depends on which version of the iPhone you have and how accurate you need the reading. In newer iPhones, the Compass app gives elevation.
Title: Re: Altimeter
Post by: DaveT on August 20, 2017, 01:38:39 pm
Unless your phone has an barometric pressure sensor it is using GPS for altitude. iPhone's older than 6/6+ do not have a pressure sensor and can only show GPS altitude. Per Garmin (https://support.garmin.com/faqSearch/en-GB/faq/content/QPc5x3ZFUv1QyoxITW2vZ6) it is not uncommon for GPS elevations to be off +/-400'.

If you do have a newer iPhone be sure and use an app that is displaying the barometric altitude  and not just the GPS altitude. You must calibrate the barometric altimeter frequently using a known altitude or atmospheric pressure. Here is an app that claims to do this (I just found it with Google, have not tried it)

Depending on your needs you could also record the GPS coordinates and look up the elevations later on a web site like https://www.daftlogic.com/sandbox-google-maps-find-altitude.htm
Title: Re: Altimeter
Post by: crashmbro on August 21, 2017, 06:47:08 am
Thank you. Much appreciated.


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Title: Re: Altimeter
Post by: dancingcyclist on September 02, 2017, 10:31:26 pm
When "Ride with GPS" records me doing50+mph down hill where it is physically impossible I will never fully rely on GPS. I wear my watch which has an altimeter/barometer when riding and want info about my altitude when climbing hills.