Opti-Logic manufactures several Hypsometers http://www.opti-logic.com/lh_series.htm
they have 2 and 3 point height measurements. On Jan 3, 2:35 pm, Carolyn Summers <[email protected]> wrote: > Are there any tree-height measuring devices that do the math for you? I > never took trig. > -- > Carolyn Summers > 63 Ferndale Drive > Hastings-on-Hudson, NY 10706 > 914-478-5712 > > > > > From: Beth <[email protected]> > > Reply-To: <[email protected]> > > Date: Tue, 22 Dec 2009 15:57:09 -0800 (PST) > > To: ENTSTrees <[email protected]> > > Subject: [ENTS] Suunto vs. iPhone > > > A Small Comparison between Suunto and iPhone Clinometers > > > Since some of us now have iPhones and have downloaded the > > Clinometer application I thought that someone needs to compare the > > iPhone to the Suunto clinometer. Today I took 14 measurements each > > while sitting on my couch to a ceiling heating/AC vent. I then > > measured my eye height, the ceiling height, and the distance from my > > eyes to the tape measure hanging from the vent as a plumb bob. These > > measurements were: ceiling height = 96², height of the eyes = 38², and > > distance to the vent plum bob = 219². I used the measurements to > > calculate the angle I was trying to measure with the Suunto and > > iPhone. Before taking my measurements I calibrated my iPhone > > clinometer according to the instructions. I also had the following > > settings: Fast approximation-on, Beep on lock-on, wait for lock > > accuracy of + 0.1o- all the way to the left (+ 0.1o), disable auto- > > lock-off, and 3D glass effect-on. > > > The first thing that I do in order to calculate the angle A was to > > calculate the distance from my eye to the ceiling; 96²-38²= 58². > > > Since Tan A = a/b, we can rearrange the equation to find A by dividing > > both sides by Tan. Since 1/Tan =Arc Tan the equation is A = (a/b) Arc > > Tan. Filling in this equation with the data we get A = (58/219) Arc > > Tan or A = 14.8336707057. Taking signifiginte numbers in mind I am > > going to say the angle is 14.8o. (Note: I calculated this after > > gathering the data as not to influence the clinometer data) > > > Now for the clinometer data: > > Suunto iPhone Suunto iPhone > > 15.5 15.2 14.5 15.4 > > 15.0 14.9 15.0 15.2 > > 15.0 15.1 14.5 15.2 > > 15.0 14.1 14.5 15.1 > > 15.0 15.0 14.5 15.7 > > 15.0 15.2 15.0 15.5 > > 14.5 15.1 14.5 15.2 > > The means were 14.8 and 15.1 for the Suunto and iPhone respectively > > with standard deviation of 0.31 and 0.35. > > > The one thing I noticed in my raw data is with the Suunto my highest > > and lowest angles were 15.5 and 14.5 whereas with the iPhone they were > > 15.7 and 14.1. I can think of at least two reasons why. 1) I have > > more experience with the Suunto than I have with the iPhone and 2) the > > Suunto has a line to help repeatly ³hit² the same spot whereas the > > iPhone you are just looking down one side of the phone. > > > I also noticed after calculating the angle (14.8) the Suunto average > > was closer than the iPhone¹s (14.8 vs. 15.1). Now is 0.3o difference > > significant? Bob has more experience with the Suunto than I do and he > > has stated in the past that can read it to the nearest 1Ž4 o. I myself > > can only read it to the nearest 1Ž2o. Given this I believe that a > > difference of 0.3o is. > > > How can the iPhone be improved? If one would add a sighting device on > > to the iPhone this could help ³hit² the same spot repeatly. Obviously > > this can not be same one that is used in the Suunto¹s, looking through > > it with an optical illusion. Maybe a tiny gun sighting built into the > > volume and/or ringer buttons on the left side. I think someone > > thought of this earlier. With the sight and practice I believe one > > could the angle down to the nearest tenth of a degree. With the > > Suunto one can only really estimate anything less than 1 degree. > > Beth > > > -- > > Eastern Native Tree Societyhttp://www.nativetreesociety.org > > Send email to [email protected] > > Visit this group athttp://groups.google.com/group/entstrees?hl=en > > To unsubscribe send email to [email protected] Hide > > quoted text - > > - Show quoted text - -- Eastern Native Tree Society http://www.nativetreesociety.org Send email to [email protected] Visit this group at http://groups.google.com/group/entstrees?hl=en To unsubscribe send email to [email protected]
