Sounds like I found the 0.2 already
One time I found a centerline pipe. There was a Survey on file which showed it a foot off. What you see is the top of a pipe which looks beat up square in a little chisel hole.
So I look at it on my hands and knees in the middle of the street because it looks funny to me. I keep chiseling and digging and soon find myself following a horizontal pipe to where it bent 90 degrees down into the ground. It actually was pretty close for the 1939 subdivision, about a tenth or so.
Some people's survey crews don't take time to investigate these pipes that were hit decades ago and bent over.
Sounds like I found the 0.2 already
we always set our pins so that the top-center is the corner.sometimes you have to drive it in at an angle if you hit a subsurface rock or ledge. so the first thing we do is try and determine if the pins we find were set tipped or pushed over or bent (hit by a mower etc).if we can't tell we shoot the top and the base. we always "double" pins, bounds etc. we use a dist-a-line (mini prism with a plumb bob and target). if you use a prism pole you need to be vigilant in keeping the level bubble in adjustment. in the case of a pin that's tipped, when we get the data back to the office we compare the base and the top to the record and make our decision as to where the corner belongs.
dave i like your described method
To be controlling a found monuments has to meet certain requirements. One of which is to be undisturbed and in its original position. It does not matter where you take your measurements as long as you provide a record of them in your notes and plats. "Found 2" iron pipe open appears disturbed, bent as it exits ground leaning southwest 0.4' out of plumb located top center of pipe, 1' above ground." I would suggest that whatever method you select that you select one that you are able to repeat.
I would suggest that with a more precise method as outlined by "Dave the Killer K Karoly" that he has a better assessment of his error as compared to the record than someone using a sloppy haphazard method. Dave can PROVE his measurement opinion, you with your single rod shot cannot, simply not enough evidence.
Is boundary surveying important? If it is, Then ought we to use methods that are commensurate with the importance of that service.
Brown state that the surveyor's obligation to the public is to provide a quality product regardless of the price.
dave i like your described method
> To be controlling a found monuments has to meet certain requirements. One of which is to be undisturbed and in its original position. It does not matter where you take your measurements as long as you provide a record of them in your notes and plats. "Found 2" iron pipe open appears disturbed, bent as it exits ground leaning southwest 0.4' out of plumb located top center of pipe, 1' above ground." I would suggest that whatever method you select that you select one that you are able to repeat.
>
> I would suggest that with a more precise method as outlined by "Dave the Killer K Karoly" that he has a better assessment of his error as compared to the record than someone using a sloppy haphazard method. Dave can PROVE his measurement opinion, you with your single rod shot cannot, simply not enough evidence.
>
> Is boundary surveying important? If it is, Then ought we to use methods that are commensurate with the importance of that service.
>
> Brown state that the surveyor's obligation to the public is to provide a quality product regardless of the price.
:good:
dave i like your described method
>Dave can PROVE his measurement opinion, you with your single rod shot cannot, simply not enough evidence.
The only thing Dave could prove is he made a few shots. What he cannot prove is that he was using the correct back sight, index, prism mode (if using a reflectorless) was right..etc etc.
10 shots to a bad spot are 10 wrong shots.
One shot is enough if you have all your ducks in a row before you take the shot.
dave i like your described method
Paul-you tell me! 😉
I try to get redundancy but sometimes the stinkin' trees get in the way and they won't let me cut them down.
dave i like your described method
What's the difference between 1 and 2 shots? 10-15 seconds maybe?
Ralph
dave i like your described method
When I say redundancy, I mean observations from different control points.
Closing the horizon or using two different BSs is reasonable in some circumstances.
dave i like your described method
> When I say redundancy, I mean observations from different control points.
>
> Closing the horizon or using two different BSs is reasonable in some circumstances.
I think I know what you mean, I don't do conventional closed traverses. I radiate every thing, using the multiple sideshot routine. So in essence I'm traversing and locating at the same setup, once I pick up I re-shoot what I want to analyze and I repeat the process. The only caveat is that when you upload to Star*Net you have to change the "SS" to "M" or else you'll get multiple coordinates to the same point.
It sounds like overkill, but it takes as long as it takes for me to walk to the point with my bi-pod.
Ralph
dave i like your described method
That is what we do, generally on smaller or open parcels.
In the timberland where the lines are 1/2 or 1/4 mile long a closed traverse is more practical but I will traverse through the middle usually following a road or something like that.
I also use GPS where practical to get more redundant ties.
PAUL, I AM NOT TALKING ABOUT BLUNDERS
Paul, you fail to understand what I am talking about. If you want to argue that it is unnecessary, then we have nothing to talk about. A single sideshot to property corner evidence does NOT provide a statistically independent measurement. A single side shot does provide a redundant measurement.
Juries are instructed to consider what is MORE LIKELY TO BE TRUE than not. So when a surveyor turns sets of angles and double ties property corner evidence and then examines that data via a least squares adjustment, can you imagine a jury concluding that the surveyor who used this process is mote likely to be able to report a more precise location than a surveyor who took a single rod shot? Substantial evidence is the basis of a sound professional opinion. A single side shot does not rise to the level of substantial evidence.
The issue is not what is good enough. The issue is not one of magnitude. The question is what provides sufficient grounds for the proper formation of a professional opinion.
PAUL, I AM NOT TALKING ABOUT BLUNDERS
> Paul, you fail to understand what I am talking about.
Bad assumption Dane...sheesh..calm down
>
> DO you locate the top of the pipe or the bottom?
>
In the area I work in northern New Jersey and southern New York, due to the very rocky soil and ledge rock, it is common for rods and pipes to be set at an angle. The norm is to set and use the top of the cap as the corner. That is not to say that there are not exceptions, if the corner appears to have shifted due to the slope slumping I will locate the top, bottom and possibly even my best estimate of where the pipe may have been originally.
We call those spinners ...
> >
> > DO you locate the top of the pipe or the bottom?
> >
>
>
> In the area I work in northern New Jersey and southern New York, due to the very rocky soil and ledge rock, it is common for rods and pipes to be set at an angle. The norm is to set and use the top of the cap as the corner. That is not to say that there are not exceptions, if the corner appears to have shifted due to the slope slumping I will locate the top, bottom and possibly even my best estimate of where the pipe may have been originally.
Because when you kick them they spin around like a top.
We call those spinners ...
That's not what "Urban Dictionary" calls a "spinner" :-O
Dan, some areas here we have the same problem. Might start the pin at the intended position, but after it finds its way around rocks it ends up at a slant, driven to refusal and sticking up. Those conditions only allow for the top to be on and to get it in place might require bending. When retracing you need to consider the ground conditions and tie what seems to be the proper location. Note the slant and height of the monument in the notes. Spinning for location on monuments set in rocky ground may be the improper thing to do.
jud
We call those spinners ...
Well, there's not much urban about northern New Hampshire.
> I usually find it easier to set a tripod/tribrach and target over it rather than a prism pole.
I like to set the instrument up over the leaning pipe. But it's very important to get the vertical axis of the instrument set to precisely the same angle as the pipe. This way, your laser plummet can shoot all the way to the bottom of the pipe. I tried for hours hanging a plumb bob down, but I could never get it to hang at the same angle as the pipe. Go figure.
PAUL, I AM NOT TALKING ABOUT BLUNDERS
Dane,
I agree and turn multi-sets d & r to corners, BUT it takes a very good Attorney to explane that to the jury.