Talking with some fellow surveyors - some work in the field, some in the office, some both.?ÿ Various ages.?ÿ Licensed and unlicensed.?ÿ We were discussing how well we can set a monument (typ. rebar or pk), and the opinions really varied. ?ÿ The point of the discussion was not how accurate our measurements/equipment is, but how well can put something in the ground.?ÿ Some stated a dimension based strictly on the accuracy of the equipment [2mm + 2 ppm 🙂 ], some said it was the measurement tolerance required by code for the survey class, one said 6", someone said 1'.?ÿ Somewhere between 0.1' and .0.2'?
Your opinion:?ÿ Using standard robotic methods at a normal pace, how accurate do we really set markers??ÿ What if we are using rtk/vrs GPS (5-10 sec obs)??ÿ Put a number on it.
I think it also depends on how plumb you can drive the rebar, most of the time I can drive the rebar straight down, others times I had to pound on the ground next to the rod to get the Cap where it needed to go, also in a gravel road, it goes where it wants to go.?ÿ
Exactly - one reason why the equipment is not the limiting factor.
I remember this old argument...
The answer, from a long time ago, was 0.04'
If I get a rebar within .02 while setting I call it good. Adding in rod plumb error, rod wiggle (not holding steady) and traverse error, I would say I'm within .05 most of the time. Plenty close for what I do.
I mostly do urban/suburban work, and I try to get the monument within 0.02' of the desired location.?ÿ (The post-processed position of the monument sometimes comes out slightly father off, but rarely more than 0.03'.)?ÿ Using a copper disk in concrete makes it pretty easy to set the punch mark inside that tolerance.?ÿ Rebars are more challenging, but I try nonetheless.
Nobody ever accused me if working fast, though.
Using a copper disk in concrete makes it pretty easy to set the punch mark inside that tolerance.?ÿ
Those copper disk are great. Thanks again Jim for responding to my questions about these markers a year or so ago.?ÿ
Sorry for hijacking the thread....?ÿ
2" caps are important ??ÿ
Just like "how accurate can you measure?
How much of my time and equipment do you want to pay for?
Many of my surveys start with a stone mound.?ÿ I have several feet of slop before I even get into setting corners.?ÿ But when it comes to putting metal into the ground, my goal is to have my equipment tell me I am within 0.02', and I try to rotate the rod around so I can verify if my rod might not be plumb ( I do forget sometimes).?ÿ But I also realize not every rod can drive straight, not every measurement is as accurate as the manufacturer claims, wind does gust sometimes, or a horn startles you, or all kinds of other little things that make up our imperfect world.?ÿ
I??d say under ideal conditions 0.02. ?ÿI??d say 0.04 is the norm and I??ve seem a lot worse.?ÿ
He said bar or pk.?ÿ How about for the nails?
You can only set a mark as accurate as the control that dictates where the mark is to be set. Anybody can precisely pound a marker at a given distance.?ÿ
I remember this old argument...
The answer, from a long time ago, was 0.04'
I thought that was the answer to ??how far off does a mark have to be before you reject it.? Dang... it??s getting harder and harder to keep up.
I will not walk away from the monument unless it is 0.03 or lower.
