So here is a secret. Tell him not to average them but to perform a least squares after he has applied all the other corrections. All those BM’s you ran through if they were NGS monuments should have an uncertainties on the data sheet. This would be following more closely to blue booking geodetic leveling Have him come with in the fall to the NGS leveling class.
Next thing is when you have longer level runs. Have at minimum two rods and Rodman. I guy running the level. This will push you easily to the 3 miles in a day vs 3 days. Once the crew has there rythem you will look like a well rehearsed play on a stage. Smooth as silk. A good crew when use to each other and all are on their game can average 5 miles a day. But that is with a crew that is seasoned in that work.
I do like a good stoute. Or a porter lager etc.
@ chris-bouffard
What kind of differences are you seeing between published and observed values? A few hundredths, or tenths?
Pt. # 1134, 0.035' difference, 271.6' from beginning BM
Pt. # 1136, 0.014' difference, 5608.6' from beginning BM
Pt. # 1137, 0.009' difference, 8473.4' from beginning BM
Thanks, that satisfies my curiosity, in the end, one or two hundredths are not going to be earth shattering.
Are they all positive or negative or do they go both ways. Also those monuments were they all part of a single run originally or was some set from a different run and direction of the level line.
@ OleManRiver
Are they all positive or negative or do they go both ways.
Pt. # 1134, 0.035′ difference, 271.6′ from beginning BM
Field El. = 96.760 Published El. = 96.725
Pt. # 1136, 0.014′ difference, 5608.6′ from beginning BM
Field El. = 96.407 Published El. = 96.393
Pt. # 1137, 0.009′ difference, 8473.4′ from beginning BM
Field El. = 101.240 Published El. = 101.231
Also those monuments were they all part of a single run originally or was some set from a different run and direction of the level line.
The monuments are all part of a single run.
So all in one direction. That except the one outlier could be systematic in the rod itself. One piece rod or two piece rod. NGS has a published document on rod errors for digital levels. I can’t recall all of it and could be mixing a few different studies I have read old age every thing gets jumbled sometimes in my small brain lol. But two piece rods the error can be seen more in certain heights that are read along the bar . I still thank you did a terrific job and whoever was the Rodman you need to buy them lunch. In my opinion the Rodman on level runs is the most important job for accuracy. It is boring and easy to get distracted as it seems so simple. But a good Rodman is always focused on setting that rod exactly on the highest point for readings and keeping a good plumb rod etc. I use to think a Rodman watching them was like watching T-BAll kids in the outfield. Gazing all around throwing dust or grass in the air. I had a few Marines I had to watch like a hawk. It is a role that requires discipline for sure. I could teach anyone to push the button on the level to read it and yeah even reading old school the 3 wires you had a check . We used turtles a lot for turning points and it never failed the first day out one of the Rodman would pick up his turtle before we could take a BS. When you are looking at 5 to 10 miles total and you go only a few turns and that happens you know it’s not a good start. Keep doing well man keep learning. Hope to see you out this way sometime or maybe I will get a chance to head your way one day. Wherever that is.
