Level Loop
I had our crew run a big level loop with the Leica DNA 10 Digital Level. They ran 38,000 feet with over 300 feet change in elevation. They miss closed by 0.007 feet. The turns were out of balance by a total of 76 feet over the length of the level loop. What should I do with these guys? Let them adjust the loop and move on, rerun the loop on their time, or check it with Trig Levels? Sarcasm off.:-)
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- 10 Replies
Good job!
As a reward, teach them how to do the Helmert Corrections on it.
It will make a difference with 300′ feet of elevation change, (NOT in the “closure” so much, but in the accuracy of the intermediate BM/TBMs).
Loyal
> I had our crew run a big level loop with the Leica DNA 10 Digital Level. They ran 38,000 feet with over 300 feet change in elevation. They miss closed by 0.007 feet. The turns were out of balance by a total of 76 feet over the length of the level loop. What should I do with these guys? Let them adjust the loop and move on, rerun the loop on their time, or check it with Trig Levels? Sarcasm off.:-)
>
>Steve: did they run back down to close on the same point (or at a similar elevation as the starting point)?
I used a Leica digital level for years in the 90’s. We used the several piece standard rod. This rod would get “loose” with time, and cause problems. If we were running flat, or up and back down, we got good closures. If we were running from say 1200 to 1500 elevation, the closures on a “not new” rod would start getting out of whack. It was due to taking a lot of BS on the low section, and then a lot of FS on the high section. I remember a 0.25 ft misclose going up a mountain, that was OK after buying a new rod. The solution was to buy a new rod every year or two.
I now use a Zeiss (well, now Trimble) Dini 12. I busted my original Dini in a door at a dam, so now am on a second one, about 10 years or so since buying the first. Original standard rod (4 m) still works fine. Of course, they are made by the same company as the Leica rod (NIDO), but the design is different.
You didn’t mention if you were using a one piece invar. We have a 0.5 m, 2 m, and 3 m invar rods, which we use for deformations, etc. We also have a one piece 1 m fiberglass-great for gage and electric tape ties.
Dayum… that is fancy shoot’n
We ran a simple loop back to the same BM. The difference in elevation between that BM, and the point we are interested in is about 50 feet. We used the 4 meter sectional rod, but the only used 2 sections of rod to keep the shots better balanced. The rod is in fair condition. We just got a new one Tuesday. We are going to tie the other BM about 2 miles west of this BM and hope that they tie together. They are on different lines and are about 20 years different in age. We will be doing GPS observations on all of the marks, and submitting it to Opus Projects.
I first used the Leica DL in the early 90s at ODOT. It was a bit unnerving to not keep standard level notes, but i got used to it quickly.
We ran from Alva, Ok. to Cherokee, Ok. (20 miles) and back. The raw loop closed with less than 30mm error. I was impressed.
We used a DNA 10 last year with a single invar rod and closed a 30,000 foot loop within 2mm. We were very careful everything, including balancing the FS BS lengths. The level can be set up to warn you if the lengths don’t balance within whatever parameters you give it. In our case Keeping the lengths within 2m was a real pain while turning around obstacles. This level/rod combination gives amazing results.
To meet NGS guidelines you would have to balance the FS BS to certain parameters depending on the class and order, but it looks like good results can be obtained without so much worry. Good shooting!
If it were an optical level, I would tell you to send them back out and find out where they made the two 1′ compensating busts….
Cheers :beer: to your crew.
That is extremely good. I used the DNA 03, which I loved, and we would consistently get that, but it was no where close to that type of distance, not even half. Those results of due to good procedure, good equipment and a little bit of luck. GOOD JOB!!
standard response=compensating errors.
Lovely work. I’m waiting patiently for Leica to update their level so it uses the newer batteries. Then we’ll ditch the Sokkia and grab a DNA with an Invar staff.
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