Testing TruPulse 200 X

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

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dbhguru
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Re: Testing TruPulse 200 X

Post by dbhguru » Sat Dec 28, 2013 4:33 pm

Kouta,

Ed was addressing the error pattern for mechanical clinometers such as Suunto. With the electronic ones, all bets are off.

I have a pretty good method for testing the absolute angle error and also the patterns, but it is labor intensive. I do plan to test the tilt sensor of the TP 200X extensively, and will share the results.

Karl,

I'm going to adopt your method with the gate. I think it is more efficient than mine.

Bob
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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Karlheinz
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Re: Testing TruPulse 200 X

Post by Karlheinz » Sun Dec 29, 2013 2:38 am

When measuring high treetops, the clutter is often in the lower and middle strata of the forest, so that adjustment of the gate value is not critical.

Kouta & Bob,
I am racking my brain how to check the tilt sensor without expensive surveyor equipment as comparison standard. Perhaps at 0° on a water surface? What are your ideas?

Karl

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dbhguru
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Re: Testing TruPulse 200 X

Post by dbhguru » Sun Dec 29, 2013 7:29 am

Karl,

Michael Taylor uses water surface as a test. My approach is more statistical. I use a combination of instruments to include laser levels. I'll explain in a future post.

Bob
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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KoutaR
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Re: Testing TruPulse 200 X

Post by KoutaR » Sun Dec 29, 2013 8:21 am

dbhguru wrote:Ed was addressing the error pattern for mechanical clinometers such as Suunto. With the electronic ones, all bets are off.
Yes of course. I guess I forgot that most of you are using mechanical clinometers. Here over the Atlantic, we use combined rangefinder/clinometer. For mechanical clinometers Ed's suggestion is plausible.

I look forward to your and Karlheinz' clinometer tests.

Kouta

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dbhguru
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Re: Testing TruPulse 200 X

Post by dbhguru » Sun Dec 29, 2013 7:11 pm

Karl and Kouta,

My last distance test of the TruPulse 200X was flawed. I won't go into the details here, but the test I just conducted is solid. Here is a look at the comparison. Tomorrow, I move to longer distances.
TP200XBoschGLRM825Comparison.png
As you can see, the accuracy is really good for the disk target I used.

I went to MTSF and re-measured the Jake Swamp white pine earlier today. I got 172.0 feet reproducible. I got one measurement of 172.25 feet, but couldn't reproduce it. With the TruPulse 360, I gave Jake the benefit of the doubt at 172.5, but I'm going with the 200X measurements. I had the Lee Frelich pine at 165.0 feet, using the Nikon Prostaff 440. Today, I measured it with Sparky (name of my 200X), and got 164.0 feet. The Nikon often is over by approximately a foot.

Bob
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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Karlheinz
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Re: Testing TruPulse 200 X

Post by Karlheinz » Mon Dec 30, 2013 5:26 am

Bob,
what target plate did you use? I get partly different values ​​when I use different plates. Material and surface condition of the target appear to be factors that influence the measured value of the TP200X. And was the target plate roughly perpendicular to the beam?

Karl

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dbhguru
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Re: Testing TruPulse 200 X

Post by dbhguru » Mon Dec 30, 2013 2:00 pm

Karl,

I used a 3-inch diameter, yellow plastic disk. Reflectivity for the disk is moderate. All trials were performed close to eye level.

Today, I ran a second set of trials, 24 in all. Distances were to 149.625 feet, as registered by the Bosch GLRM 825. The results are shown below.
TP200XBoschGLRM825Comparison-2.png
The average difference between the Bosch and TruPulse was 1.009 inches (0.397 centimeters or 3.97 millimeters). Angles of elevation varied from -16 degrees to + 18.0 degrees. Target visibility was good.

Between the two of us, I think we're going to understand the performance of this instrument pretty well. So far, I'm extremely happy with it. I plan to begin tilt sensor testing tomorrow.

Bob
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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Steve Galehouse
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Re: Testing TruPulse 200 X

Post by Steve Galehouse » Tue Dec 31, 2013 12:12 am

NTS-

Isn't there a point of diminishing returns regarding the accuracy of the equipment? Is a Nikon 440 and clinometer 98 percent as accurate compared with a Truepulse? If so, the cost differential seems to be a burden, for me at least.
every plant is native somewhere

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Karlheinz
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Re: Testing TruPulse 200 X

Post by Karlheinz » Tue Dec 31, 2013 4:15 am

Steve,

A thorough discussion of this legitimate question, we have to perform when we tested all functions and compared with existing equipment.

Karl

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DougBidlack
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Re: Testing TruPulse 200 X

Post by DougBidlack » Tue Dec 31, 2013 7:43 am

Steve,

it partly depends on why you want to measure the height of a tree. If you only want to know which tuliptree is the tallest in a particular park then maybe you only need to be accurate to within a foot or so. But if you want to know how much that tuliptree grows every year then measuring to within a foot is not good enough.

Doug

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