> When I traverse I always have my crews wrap angles to the right regardless of the bs distance.
Aloha, Jp7191: Could you please elaborate this for me? thakss
We double all our angles and distances to traverse points
, this is set up in the data collector to allow whatever tolerances
you want. I use 15 sec and .02'. When closing each state has its own tolerances allowed. If it does not close with in tolerance we do it again.
> We double all our angles and distances to traverse points
> , this is set up in the data collector to allow whatever tolerances
> you want. I use 15 sec and .02'. When closing each state has its own tolerances allowed. If it does not close with in tolerance we do it again.
Aloha, Djames:
Thank you! By double you mean two sets right? Or...
For a traverse I use two sets, sometimes more if conditions indicate I need more. I turn all of my angles to the right as standard practice, need very careful notes and scrutiny, if you start mixing methods or directions. Have used accumulated deflection angles left or right route surveys, the notes for that needed to be watched closely so the proper direction from the projected line was clear. When I first started using the gun, I was working for a firm that had some contracts with the USACE, Their inspector told me, that to minimize returns to the field to pick up something missed was to choose a good technique and to stick with it always, even if it might seem silly to always run through the whole process. His reasoning was that if the proper habits are ingrained and something distracts you, that ingrained way of doing things would trigger a warning if the routine was broken. I have found that he was right and little time was lost doing it that way, repeated trips to a project to pick up missing or to correct a bust caused by the lack of good and consistent techniques or a distraction gets expensive.
jud
> I turn all of my angles to the right as standard practice.
> jud
Aloha, Jud: Thank you so much for the clarification. Let me repeat what I understood...That means once make your plans to traverse from point A to B then would go clockwise in order to turn your all angles only to the right....
Yswami, as Jud explains below, it can get real confusing in the field notes if you don't use the same procedure when traversing a multi leg traverse. People who want to turn from a long back sight to short fore sight will turn angle right in one setup and angle left in the next setup based on the length of sight. It can get real confusing when you try to reduce the notes. Once you realize that an angle measured between two points fixed to the ground is the same angle whether or not you measure it short to long or long to short. With that being said I always turned angle right from the back sight to the fore sight and there was never any confusion when reducing the notes. With all that said, this was in the day when we would not use a data collector to traverse, but just peg (write) our angles and distances in a field book and reduce them at the bar 😀 . About the same time data collector software was getting sophisticated enough to traverse with (no note keeping) gps became available and the days of long traverses were done so the discussion is rarely discussed anymore. Hope this helps, Jp
Many modern instruments will digitally read the angle-right, or the angle-left. It isn't how you turn the scope, per se, but that you are reading the same angle you would get when you turn the scope to the right. If the angle right is 90 degrees, the angle left would be 270 degrees.
AS to 'doubling angles': today it means reading the angle twice. Sometimes reading the same angle, by backsighting and foresighting the same points, sometimes it means by inverting the scope so you read it once "direct" and once "reversed" (also known as face one and face two)
With older instruments with two circle-plates, "Doubling" meant backsighting with 0º in the vernier, and loosening the upper plate and turning to the foresight, locking the upper plate, and reading the "angle-right". Then you would reverse the scope, loosen the lower plate, aim at the backsight again with the same original angle in the instrument, lock the lower plate, loosen the upper plate and turn the angle to the foresight. The resulting angle would be close to "Double" the original. To get the "Mean angle right" you would take the doubled angle and divide by two. (if the second angle made you go past 360.....you would add in the 360 before you divided for the mean.) (an example: first angle = 186º00'15" "doubled angle"=12º00'26" add 360 for 372º00'26", and divide by two for 186º00'13"
Older transits used to read angles left or angles right on the external vernier.
Some of the more precise older theodolites would not have two plates, and you would not "double the angles" but often "close the horizon". That entailed backsighting the backsight turning the angle right, then backsighting the foresight and turning the angle right to the backsight. This would end up with two angles that should add up to 360º, To get the mean angle right, you would take the difference of how close you came to 360º and apply the negative of half of that to the first angle. ie: if your two angles added up to 360º00'14", you would subtract 7" from your first reading to get the "mean angle right".
Okay, that was convoluted, and you probably didn't want to hear all that. But the second paragraph is where the term "doubling angles" came from in my opinion.
> Many modern instruments will digitally read the angle-right, or the angle-left. It isn't how you turn the scope, per se, but that you are reading the same angle you would get when you turn the scope to the right. If the angle right is 90 degrees, the angle left would be 270 degrees.
>
> AS to 'doubling angles': today it means reading the angle twice. Sometimes reading the same angle, by backsighting and foresighting the same points, sometimes it means by inverting the scope so you read it once "direct" and once "reversed" (also known as face one and face two)
>
> With older instruments with two circle-plates, "Doubling" meant backsighting with 0º in the vernier, and loosening the upper plate and turning to the foresight, locking the upper plate, and reading the "angle-right". Then you would reverse the scope, loosen the lower plate, aim at the backsight again with the same original angle in the instrument, lock the lower plate, loosen the upper plate and turn the angle to the foresight. The resulting angle would be close to "Double" the original. To get the "Mean angle right" you would take the doubled angle and divide by two. (if the second angle made you go past 360.....you would add in the 360 before you divided for the mean.) (an example: first angle = 186º00'15" "doubled angle"=12º00'26" add 360 for 372º00'26", and divide by two for 186º00'13"
>
> Older transits used to read angles left or angles right on the external vernier.
>
> Some of the more precise older theodolites would not have two plates, and you would not "double the angles" but often "close the horizon". That entailed backsighting the backsight turning the angle right, then backsighting the foresight and turning the angle right to the backsight. This would end up with two angles that should add up to 360º, To get the mean angle right, you would take the difference of how close you came to 360º and apply the negative of half of that to the first angle. ie: if your two angles added up to 360º00'14", you would subtract 7" from your first reading to get the "mean angle right".
>
> Okay, that was convoluted, and you probably didn't want to hear all that. But the second paragraph is where the term "doubling angles" came from in my opinion.
Aloha, Tom: I actually needed to hear all these. I guess unless one is "raised" with the older instruments some of these terminology just goes over our heads! At least that's what happening to me. I personally always wanted to know why I am doing what I am doing instead of just pushing the buttons and looking at the results.
If I use robotic instrument all these are not relevant right, except I may need to collect multiple sets so that I have a bit more precise measurement?
Thank you again for taking the time to explain these details with examples!!:good: :good:
> For a traverse I use two sets, sometimes more if conditions indicate I need more. I turn all of my angles to the right as standard practice, need very careful notes and scrutiny, if you start mixing methods or directions. Have used accumulated deflection angles left or right route surveys, the notes for that needed to be watched closely so the proper direction from the projected line was clear. When I first started using the gun, I was working for a firm that had some contracts with the USACE, Their inspector told me, that to minimize returns to the field to pick up something missed was to choose a good technique and to stick with it always, even if it might seem silly to always run through the whole process. His reasoning was that if the proper habits are ingrained and something distracts you, that ingrained way of doing things would trigger a warning if the routine was broken. I have found that he was right and little time was lost doing it that way, repeated trips to a project to pick up missing or to correct a bust caused by the lack of good and consistent techniques or a distraction gets expensive.
> jud
Aloha, Jud: Thank you. One of the reason I began to post on this forum is create a routine for myself and stick to it. What I will be doing is much less complicated compared what all of you do in your day to day job. However, I am want to set a higher standard of practice for myself.
Digression...As a monk the precision and quality of our external work directly impact our internal qualities. Similarly the internal behavior and attitude impacts the external duties.
Thanks again for bearing with all my questions! All of yours and others' help are very much appreciated! All of you are my survey Angels :angel:
Turning angle to the right can be done while traversing along a traverse clockwise or counter clockwise. Turning to the right means that you sight your BS, set 00° 00'00" or whatever and turn to the right to the FS.
When closing the horizon we did the same but went on around to the right to the BS, recording the angles as we went. Then we would flip the scope, aim at the BS and record what was on the circle, then turn to the right to the FS and then continue to the right to the BS, again recording the angles as you go. We never set 0°00'00 into the gun when we first orientated on the BS, always set close to 0°00'20" as the starting angle, reason for doing so was to keep all readings to the BS on the same side of 0°00'00" so note reduction would be easier, getting a 360°59'42" or a 179°59'42" in the mix was a pain. We didn't worry about the total angles when closing the horizon adding up to near 360°. Reducing the notes amounted to averaging the 4 sights to the BS and the 2 to the FS to obtain the average seconds. Using the Degrees and minutes from the first sighting to the FS and adding the average seconds would provide the base number and all you needed to do then was to subtract the 00°00' from the first sighting to the BS with the average of the seconds to obtain the true angle. That is one set and any number of FS could have been included in that set if one or more side shots were needed, just pick them up as you work around the circle. Today I seldom close the horizon, but turn my angles as above with the exception of the second sighting to the BS. My other half runs the gun for me and she turns each set as follows, BS, FS, FS and BS, when I run the gun I still shoot the BS, FS, BS and FS, end up with the same results so I don't make her change the way she learned.
jud
Thanks Jud!
I see what you are saying and I will agree.
You need some way of "flagging" weak measurements and deal with them.
My only added explanation would be that:
-At that point in time nobody had heard of, what you call it, ugh, "Least Squares" 😉
-All that would be used to adjust is simple Compass Rule on mis-closure.
-Doubt the PC would have eyeballed the traverse and done anything other than a straight sum the angles and throw equal amounts into each setup type angle adjustment.
Serious.
-Unless I did some mental phenegeling while recording to make the measured angle sets "match", (T2, maybe 4 or 8 positions Direct/Reverse) the PC would have me re-do setup as it was sloppy. Angle turning was a lot of work!
(I feel silly talking like GrandPa about walking to school 3 mi... in snow but this was like early 1980's. Often used Wild T3 also. That's WORK but fun too.)
>
> (I feel silly talking like GrandPa about walking to school 3 mi... in snow but this was like early 1980's. Often used Wild T3 also. That's WORK but fun too.)
Aloha, Bob:
Please don't feel that way. I appreciate all the detailed and historical account of surveying. Thank you!
