James,
BVP was independently using the sine top sine bottom method first. There may have been others as well, but I'm unaware of who they would have been. Will Blozan and I developed sine top and sine bottom for ENTS. We later discovered that BVP and been using it for a long time. Colby Rucker later joined Will and me and became known for his use of long poles to get a better fix on the lower measurement. Colby was just great. I miss him a lot. We all do. BVP was the one who introduced Will and me to the Litespeed 400, a Bushnell laser. I got one and so did Will. Everything was uphill thereafter. The rest is history. In terms of the tree math, my strong suit has always been mathematics. I developed mathematical models in my work while in the Pentagon and have taught math and statistics at the college level. So, tackling the problem in a mathematical way conforms to my nature. I say this because it has always come as a surprise to people outside the world of forestry that such basic calculations as we use haven't been in practice for decades. I always explain that those calculations were not possible prior to the introduction of the laser rangefinder. As to the expertise of mensurationists, they know the math. It's elementary, but they don't spend the time decoding hard to measure trees in forest situations. It's rather like knowing some principles of animal tracking versus being out there doing it. It took me three separate trips to tie down that tuliptree in Montpelier. I'm within +/- 0.5 feet of the twig I was measuring, but the effort required speaks to the difference of pointing, shooting, and writing down some numbers versus getting it right. ENTS knows better how to do that than any other group in the East. Of that, I have no doubt. The Forestry 550 does measure tree height by our sine top, sine bottom method. The TruPulse does it also, but not by the built in height routine. It requires mores steps. BVP's Impulse Laser also does it right, but not by the built in routine. He also must use more steps. The OPTILOGIC appears to do it by the old tangent method. Pity. Before ENTS people were using laser rangefinders in sports and other endeavors, but judging by the feedback we have gotten, ENTS has been really the only show in town in terms of employing laser rangefinders in tree height measuring. There's no way of knowing who might have been out there in tree-land doing it on their own. They didn't come forward. The tangent-clinometer method was used before ENTS. It has been in use for decades. I suspect that early measurements of standing trees employed this method with some instrument being used to measure the vertical angle. The method of similar triangles would also have been used. Descriptions of equipment used and measuring methodology have been lost, if they were ever known. Thus, we get reports of astounding tree heights, but no way of verifying them. We'll never know what grew in centuries past. A laser by its self can be used as you describe. However, looking upward and trying to shoot exactly straight up (90 degrees) is harder than one might imagine. When you think you are looking straight up, it is often at an angle of 70 to 75 degrees. A short make shift plumb bob can be used to create a true vertical line. I think this covers everything. Bob ----- Original Message ----- From: "James Parton" <[email protected]> To: "ENTSTrees" <[email protected]> Sent: Monday, January 4, 2010 10:47:21 PM GMT -05:00 US/Canada Eastern Subject: [ENTS] Re: Suunto vs. iPhone Bob, ENTS came up with the Sine-Top Sine-Bottom method of measuring, right? I also know that some others have used lasers to measure trees more recently? Has ENTS inspired the use of laser rangefinders as tree measuring tools so much to grab Nikon's attention to build a laser specifically for measuring trees? And then there is those Tru-Pulse lasers and the one that BVP uses. Was lasers being used of any frequency before ENTS? I have always thought the tangent clinometer- only method was in use before You and Will developed our highly accurate method. I also know that a laser can be used by itself from under the tree if the top can be found as in a decideous tree in winter without the need of the clinometer. Fill me in on laser usage history. James Parton On Jan 3, 3:19 pm, [email protected] wrote: > Carolyn, > > The Nikon Forestry 550 does it all. It is also fairly pricey. You select the > height mode, shoot the crown, shoot the base, and read the calculated height > from the LED. No math. No fuss. No bother. > > Bob > > > > ----- Original Message ----- > From: "Carolyn Summers" <[email protected]> > To: [email protected] > Sent: Sunday, January 3, 2010 2:35:23 PM GMT -05:00 US/Canada Eastern > Subject: Re: [ENTS] Suunto vs. iPhone > > 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] > > -- > 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] -- 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]
