calculation problem

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

Moderators: edfrank, dbhguru

User avatar
gnmcmartin
Posts: 464
Joined: Thu Mar 11, 2010 7:16 pm

calculation problem

Post by gnmcmartin » Thu Apr 15, 2010 9:06 pm

ENTS:

I have bought measuring equipment and have been trying to learn how to use it. I am not having any difficulty with the range finder or the clinometer—I think I am getting good data, although I may get better with practice.

The problem is the calculator. I have a Texas Instruments TI-30X IIS. The problem seems to be that I don’t know how to set the calculator so it can do the trig functions as described in Ed Frank’s step-by-step input sequence. When I put in the angle from his example, 47 degrees, and then press the sin button, all I see is the left side of a parenthesis and a flashing upright rectangle, which I assume is like a computer cursor, telling me it is ready for more input rather than presenting me with the sin value. I have experimented with pushing different buttons, but I get nothing.

In the instructions for trig all it says is “enter trig functions (sin, cos, tan, sin -1, cos -1, tan -1), just as you would write them. Set the desired angle mode before starting trig calculations.”

I have done the latter, setting it for degrees.

So, what am I missing here? Do I need a table of the sin values? It seems the calculator is asking me for the sin number. But my understanding is that the calculator should present that to me so I can then multiply that by the distance from my eye to the tree top.

--Gaines

User avatar
edfrank
Posts: 4217
Joined: Sun Mar 07, 2010 5:46 pm

Re: calculation problem

Post by edfrank » Thu Apr 15, 2010 9:15 pm

Gaines,

Many Texas Instrument calculators use an input style calle RPN. It was always so awkward and counter-intuitive to use, I opted to simply not use RPN calculators at all. This is likely what is happening, and I can't tell you how to use that format of a calculator. My calculator cost $9 with trig functions, so one solution would be t buy a calculator that doesn't use RPN.

Ed
"I love science and it pains me to think that so many are terrified of the subject or feel that choosing science means you cannot also choose compassion, or the arts, or be awe by nature. Science is not meant to cure us of mystery, but to reinvent and revigorate it." by Robert M. Sapolsky

User avatar
Beth
Posts: 90
Joined: Tue Mar 09, 2010 12:55 am

Re: calculation problem

Post by Beth » Thu Apr 15, 2010 9:30 pm

Gaines,

I have noticed that some calculators require you to put in the number then hit the trig function and some it the reverse hit the trig function then the number...examples....lets say your measurements are 20 degrees height at 30yds (90ft) in the first case you would hit sin --> 20 --> X --> 90 = 30.78181289931. The second case the sequence would be 20 --> sin --> X --> 90 = 30.78181289931.

Does that help?
Trees are the Answer

User avatar
gnmcmartin
Posts: 464
Joined: Thu Mar 11, 2010 7:16 pm

Re: calculation problem

Post by gnmcmartin » Thu Apr 15, 2010 10:35 pm

Beth:

That's it! If I enter the distance from my eye, then "sin," and then the angle, I get my answer.

--Gaines

User avatar
James Parton
Posts: 1576
Joined: Wed Mar 10, 2010 5:47 pm

Re: calculation problem

Post by James Parton » Fri Apr 16, 2010 4:55 am

Gaines,

I initially bought a Texas Instruments calculator and took it back. I did not like the way it worked. I have a Casio now and it works great!

James.
James E Parton
Ovate Course Graduate - Druid Student
Bardic Mentor
New Order of Druids

http://www.druidcircle.org/nod/index.ph ... Itemid=145

User avatar
dbhguru
Posts: 4519
Joined: Mon Mar 08, 2010 9:34 pm

Re: calculation problem

Post by dbhguru » Fri Apr 16, 2010 7:21 am

Gaines,

The solution is a cheap Casio. Texas Instruments calculators are counter-intuitive. They're a royal pain. Casio calculators rule. TI calculators suck.

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

User avatar
gnmcmartin
Posts: 464
Joined: Thu Mar 11, 2010 7:16 pm

Re: calculation problem

Post by gnmcmartin » Sat Apr 17, 2010 8:31 pm

Thanks for all the help/suggestions guys. I paid only about $12 at Walmart, and since Beth's changed input suggestion works, I am fine. I won't use all the other functions on this thing, which would probably confuse me if I did. Right now I am fine. I have been a little slow to get going with this measuring business because of time problems. But this is fun--I hope I don't get a real bad case of some kind of measuring bug.

I have some data to report--preliminary and sketchy as it may be. I will get to that as soon as I can get the data and the pics ready.

--Gaines

User avatar
dbhguru
Posts: 4519
Joined: Mon Mar 08, 2010 9:34 pm

Re: calculation problem

Post by dbhguru » Sun Apr 18, 2010 3:16 pm

Gaines,

Sorry, but we do hope you'll catch the measuring bug. We need data from your area, especially the West Virginia sites. We need examples of the best that you can find correlated to site factors such as moisture, soil, protection, etc. The value as Ents that we have, or potentially have, is best realized through the unique data that we collect and collate into useful lists and reports. The more data we collect and present, the bigger impact we will have.

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

User avatar
Don
Posts: 1569
Joined: Tue Mar 09, 2010 12:42 am

Re: calculation problem

Post by Don » Sun Apr 18, 2010 9:40 pm

Bob/Gaines-
While I've growled with others on calculators using RPL (I was always told it was Reverse Polish Logic, but now wonder if it wasn't an ethnic joke, not here intended), my current preferred 'tree height' calculator is my $30 Texas Instruments TI-30X II S. Quite a title, but it's fairly basic. What I like most about it, is it has enough screen display to contain significant portions of the formulas we use...that way, I get to more easily check my input data. Comes in a hard case, with a clever hard cover.
Don Bertolette - President/Moderator, WNTS BBS
Restoration Forester (Retired)
Science Center
Grand Canyon National Park

BJCP Apprentice Beer Judge

View my Alaska Big Tree List Webpage at:
http://www.akbigtreelist.org

User avatar
dbhguru
Posts: 4519
Joined: Mon Mar 08, 2010 9:34 pm

Re: calculation problem

Post by dbhguru » Mon Apr 19, 2010 6:35 am

Don,

My understanding is that in early computer logics, it was easier for programmers to build software subroutines to do internal calculations using RPL. From my early days doing some machine and assembly language programming, a for sure masochistic practice, I'd say that would be true. Thank God, we're beyond those days.

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

Post Reply

Return to “Measurement and Dendromorphometry”