General discussions of measurement techniques and the results of testing of techniques and equipment.

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Post by dbhguru » Fri Jan 10, 2014 2:30 pm


Don Bertolette and I are working on an article for the Journal of Forestry's Field Notes on new equipment items and iPhone applications. On this article we are concentrating on Theodolite, an iPhone/iPad app. Theodolite measures horizon and elevation angles, and azimuth. The app allows the user to measure the height of a vertical object by marking the top and base of the object looking through the camera lens. The horizontal distance is then supplied to a calculation routine to obtain the vertical height of the target. Here is a screen shot using Theodolite.
The target is a section of the white oak across the street. You can see a yellow disk on the trunk. From the point I took the measurements, the 3-point tangent routine of the TruPulse 200X gave a height 31.583 feet. On a horizontal target distance of 127.333 feet supplied by the TruPulse, the Theodolite routine gave a height of 31.73 feet. The difference between the TruPulse and Theodolite amounts to 1.8 inches. This is actually a test of the two clinometers in terms of how close they are. The challenge is to mark the top and base of the target through the camera lens. This can easily be the source of significant error. Lots of practice is essential for the use of this app.

Robert T. Leverett
Co-founder, Native Native Tree Society
Co-founder and President
Friends of Mohawk Trail State Forest
Co-founder, National Cadre

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Larry Tucei
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Re: Theodolite

Post by Larry Tucei » Sat Jan 11, 2014 12:39 pm

Bob- Any chances of working with an Android App? Larry

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Re: Theodolite

Post by Don » Mon Jan 13, 2014 1:39 am

I do believe that Hunter's Theodolite can be run on Android platforms...
Don Bertolette - President/Moderator, WNTS BBS
Restoration Forester (Retired)
Science Center
Grand Canyon National Park

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