"idiotic"
> > As for being "idiotic", That doesn't bother me at all. I've got an excuse!
Actually, perfectly intelligent people do perfectly idiotic things from time to time. It's to be avoided, though. Look at it this way: at least he wasn't laying down in the center of a county road. :>
I'm not sure which method you want to do it, I think it's a matter of habit, or how you like to calculate it. Your just reading two different positions on a circle and subtracting the difference to get the angle (in essence). Doing it on both faces, and multiple times, just provides checks that you read it right, and a better estimate as to what the angle is. Using "two sides" of the circle, is just a different methodology to get the same result...it's just like the difference of whether your reading the angle left or angle right. Turning the "internal" angle and the "external" angle should add up to 180°00'00" whereas "doubling" the angle means that you can divide the "doubled" angle by two to get the mean.
The relevant difference simply goes back to whether you had an upper and lower plate or all on one plate back when we used theodolites. Kent's right since new total stations no longer have the two-plate option. Everyone is idiotic to Kent, so that means he likes you and you have risen to no longer being a "non-person" (as paden said) (sorry for the double-negative).
OK OK OK
I too have no problem with someone telling me that I did/do something idiotic.
However, that being said, I WOULD appreciate it, if that statement were
followed by clear and concise directions and or procedure for accomplishing
the task "un-idiotically".
Thanx,
Geezer
(As in a name, not a description, which would be proceeded with "Old".
Yes , I am old, but that adjective preceeding may name, might imply that
I couldn't/wouldn't accept direction)
Actually, I don't have a problem with "Old Geezer - my wife does! But I quickly
remind here that SHE is a Grandma - not me- THAT is followed by glaring looks
and long silence. LOL
> The relevant difference simply goes back to whether you had an upper and lower plate or all on one plate back when we used theodolites. Kent's right since new total stations no longer have the two-plate option. Everyone is idiotic to Kent ...
No, that's hardly true, but using a direction instrument in the way that a 1940's-vintage surveying text described using a repeating transit, and without considering what is actually being accomplished is pretty dumb considering that measuring angles is such a fundamental surveying operation.
rfc,
Here's another simpler method of doubling an angle. Some of the purist here will no doubt have a knipsh*t, but that's their problem.
Zero on your back sight. Turn your first angle right to the target.
Book the angle and shoot the distance and record in your field book.
Flop the instrument and re-zero on the back sight. Yes. Re zero. Turn your second angle to the target and shoot the distance and book the info. Looks like this in the field book.
Target ID________________Angle_________H.D.
Point # Description
D: _____________________180-01-05_____555.55'
R: _____________________180-00-55_____555.50'
M: _____________________180-01-00_____555.525
The advantage to this method is you can do the math in your head on the spot and know if your angle is acceptable before breaking down your setup and moving ahead.
If the angles aren't closing satisfactorily, check your gun isn't out of level and repeat as necessary.
Carry on good man.
"idiotic"
>
> Coming from Kent, I wouldn't take the term "idiotic" personal either. I think he uses it as an endearing term of affection...:pinch:
paden:
No, I'm serious. I don't take it personal at all now. I've been doing this now educationally for what...6 months or so? I'm amidst a great number of folks who have legions more experience than me. I'm here to learn and that's what I'm doing. I'm a happy camper, and have come to enjoy the occasional "outbursts";-)
That said, I found many posts by me on various subjects wherein I've explained in detail what I've been doing, how I've been doing it, and what instrument I've been doing it with, and never once has ANYONE (until now that is), picked up on the fact that measuring an angle twice in a row on the same face, is, from an instrument's operation point of view, useless. It may help eliminate reading and recording (I'm using a field book) mistakes, but it does NOTHING towards increasing the probability of a measurement being correct. Measuring on both faces though (one measurement on each), will.
:good:
for rfc:
Do three sets, turn the tribrach 120 degrees each time.
BS Face1 at zero
FS Face1 at, for example, 90.
FS Face2 which would be 270 in our example
BS Face2 which would be 180.
Wilwaw, that doesn't sound like a bad method to me. I'm a fan of turning angles more than once to detect blunders and such. Whats nice about the method I use is the second angle is different than the first. In others words using your method it would be easy to look at the first angle and write down the wrong answer again. In other words your wrote down 91-43-34 when you should have wrote down 91-34-43. It would be easy to write down the same angle wrong the second time.
Idiot a term of affection. I never looked at it that way, Kent I think your an idiot too!
> rfc,
>
> Here's another simpler method of doubling an angle. Some of the purist here will no doubt have a knipsh*t, but that's their problem.
>
> Zero on your back sight. Turn your first angle right to the target.
> Book the angle and shoot the distance and record in your field book.
>
> Flop the instrument and re-zero on the back sight. Yes. Re zero. Turn your second angle to the target and shoot the distance and book the info. Looks like this in the field book.
>
> Target ID________________Angle_________H.D.
> Point # Description
>
> D: _____________________180-01-05_____555.55'
> R: _____________________180-00-55_____555.50'
> M: _____________________180-01-00_____555.525
>
> The advantage to this method is you can do the math in your head on the spot and know if your angle is acceptable before breaking down your setup and moving ahead.
>
> If the angles aren't closing satisfactorily, check your gun isn't out of level and repeat as necessary.
>
> Carry on good man.
I like that too! Not using a DC, it's a big problem if you don't pick up a blunder in real time. This makes it really easy to see a mistake. Thanks.
Valid point. But the odds of transposing two sets of observations and having them agree to within 10" is a bit of a stretch. I have done it with one and of course the angles don't agree so I turn another set. If it's a particularly long and critical shot I might average out half a dozen D&R angles. The goobers tend to jump out that way. In my early PC days I use to book everything and compute the traverse as I went on my HP48 using a simple program I wrote. It was good practice and kept me occupied at the gun while waiting for the rodman to get in position for the next shot.
As for idiots, I reserve that term for politicians and that is a big no no in Wendel's book of beerleg etiquette. 😉
"Sometimes I wonder whether the world is being run by smart people who are putting us on, or by imbeciles who really mean it."
~Mark Twain
> No, that's hardly true ....
What's hardly true? I'm missing something.
We use to have to check angles, slope stake and make plane table calculations in our head. It was faster than using a calculator. Now most people need a calculator to fill out their timesheet. Have no desire to go back, but our brains are turning to mush. How many party chiefs could survive with a field book and Field Tables?
Kent, you are right, but the problem you are addressing is down the road after he figures out a bigger problem.
If he can point the instrument with any reasonable accuracy then he should be getting much closer to the same angle increment each time. He and the instrument should be able to do that before we worry about averaging out the errors in the graduated circle.
> > No, that's hardly true ....
>
> What's hardly true? I'm missing something.
Your idea that I consider everyone to be idiots. That's hardly true.
I don't see the point some have made about the instrument not being level. That would give you inaccurate angles, but have no effect on repeatability.
I'm wondering about the tribrach or tripod being loose.
Point at the backsight, lock the motion, twist the base of the instrument to the right so you see the image deflect by some fraction of the field of view. Release and see where you are pointing. Twist the base of the instrument to the left and release. See where you are pointing. They should come back to the original pointing within a distance corresponding to a very few seconds of angle. If not, you have something loose in the tripod or tribrach.
Repeat by very gently twisting the telescope or instrument body, maybe enough to move the image 30 seconds or maybe the distance between the double lines in the reticule if you have them. Does it come back close after either right and left?
If that checks out ok, try this: BS, zero, measure an angle right. BS, zero, measure angle left. BS, zero, measure angle right. How much difference is there between right and 360-left?
> Kent, you are right, but the problem you are addressing is down the road after he figures out a bigger problem.
>
I agree, and I don't know yet what it is. I just recently completed the somewhat exhaustive "Kent Test III" TS Direction Accuracy test, so I don't think it's the base accuracy of the instrument, as David Livingston has suggested. The thing came through with flying colors (close to 4" for directions).
To confirm this, I'm going to pick some more observations I've already done, at random and see if I'm getting the same results. And finally, if I can't determine what's wrong from that data, I'll go back and re-measure one or two angles using only one measurement on each face, and finding the mean of the two, and then compare to the measurements I've already taken.
And finally, finally, I can always pick a new setup, repeat my procedure precisely, record the results, then do it as others here have suggested (Single measurement FL, flip, zero, single measurement FR). And compare to the first procedure.
> :good:
>
> for rfc:
> Do three sets, turn the tribrach 120 degrees each time.
>
> BS Face1 at zero
> FS Face1 at, for example, 90.
> FS Face2 which would be 270 in our example
> BS Face2 which would be 180.
I hope you're not telling me surveyors do this routinely:-O
Doing it three times from three different positions of the tribrach, will give you a good test on your instrument, to see if you're getting the same angle from three different locations on the plate. Turning the tribrach 120 degrees each time so that you are getting the full tribrach on the top of the tripod. Surveyors don't do this routinely (as far as I know) on every traverse, but it is a good instrument check (as long as you can turn the same angle all the time).
As far as I know, we still don't know what his targets are. If it's a short sight to a prism pole 40" isn't that much - only 0.02' at 100' and of course proportionately less at shorter ranges.
"idiotic"
> > an endearing term of affection
If arrogant condescension comingled with haughty derision and myopic self-importance is affection, I think I'll chose tepid indifference.
