We live in a very modern world with equipment we only dreamed about three decades ago, so this is what is confusing me. Large commercial subdivision from 2017 tied to the section and quarter corner. Both monuments have been there for years, very substantial and in the open. No canopy nearby. I get 2650.04, another surveyor 2650.08, another 2650.06 feet. I use a Leica 1200 with a bipod and average each shot five times. I don't know how my peers got their shots, with or without a bipod.
The subdivision lots all work mathematically to the hundredth, so someone knew what they were doing. There are no "original" lot corner monuments, but I did find some older plat boundary monuments and matched two to the hundredth. The rest are mostly gone, destroyed by construction.
Brand X got 2649.92, and I'm missing his lot corner monuments by over two tenths. These were set after paving so weren't shoved over by construction. How can you screw up that badly, or am I being overly critical.
Bumped control? GPS Scale factor? Bad equipment? There's always something to look at. I had a project site that had a section corner we tied in the middle of an intersection, and three years later tied it again in another survey. It was off by nearly 4 tenths. Turns out a sewer contractor, disturbed it, and reset it themselves "pretty close". The county reset it to the original position, but there was a series of years where different surveys were done and recorded in the area using it.
Maybe the other "Brand X" would check their stuff if it was pointed out??ÿ
My money is on a bent rod
Brand X could be a bad surveyor. -OR- the site conditions may have changed since the monuments were set (bad things happen). I recently saw a subdivision where the original engineering/surveying crowd's CL street nails in the asphalt had already been damaged & that the 1-2 year old pavement was cracking in several places (30+ lots in a rural residential subdivision). The streets have not even been accepted yet by DOT from what I was told but the guys clearing & grubbing these lots (public water & septic) have done a number to the pavement.
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The firm I worked at last had to go back to a site & check in on some property corners in a newly platted subdivision. Several lots had their home construction commence within like a week of recording the plat. By the time our firm went back a couple months later, the fencing companies had actually either removed or relocated the rebar corners (some by over a foot or more) from what the original monumented shots had been. And all this was noted from control that was undisturbed & set off of the site. Fencing contractors, electrical/comms, landscaping guys & others are always notorious culprits when development is involved. I went to a site 3 weeks ago & the small, single phase pad-mounted transformer had 8" of elevation difference from the front to back & was set right at the property corner too haha. Gives you the warm & fuzzies on that monument's location knowing that such care was involved in setting the transformer
If they are using GPS and conventional this is easily explained through relative accuracy and doesn??t mean their is any worse than yours. Most stuff is better than 0.07 +- 200 ppm. But, that would potentially account for the error.?ÿ
Or they just don't calibrate the bubble often enough.
When three surveyors agree within 0.02 of their combined mean, and the fourth differs by 0.14, and then there are other discrepancies of "over two tenths" on lot surveys, it is a prima facie case that the fourth is not as careful a measurer.
Multiple tenths probably doesn't meet standards for urban surveys.
If they are using an EDM the first thing I'd check is the prism offset.?ÿ I speak from experience.
Andy
Tight urban, zero lot lines, expensive condos, yeah 2 tenths can be an issue. Tract homes, 8' sideline set back lines, big yards, then probably no.?ÿ
It always depends with surveying.?ÿ
There are no "original" lot corners
I'm guessing but if this is one of those newer subdivisions where the platting is first, the dirt gets moved, utilities installed and then lot corners are monumented these monuments may be the "original corner monument". Might not like it, but you are probably stuck with it, unless it's causing undo harm to a property owner.?ÿ
This is what the modern platting regulations have caused, I'm not complaining about it, it's simply a function of the process anymore.?ÿ
My sympathies for this is limited, I've been through the process many times and the platting surveyor should take some of the blame. If there are not pins, but the plat shows pins and there never were pins, he may be liable to set them.?ÿ
When I worked in Eugene the surveyor, as part of the subdivision process, was responsible for making a security deposit to the City in an amount set by a base number plus a certain amount per monument that was returned upon verification of the monuments being set. Lot corners were set at the time of approval, centerline monuments waited until after paving.
It's similar here, but more disturbance it sounds like. The site is normally stripped of topsoil first, no point in monumenting it. Then grading if necessary, underground utilities including drainage pipes, then roads, curb and gutters, ect. Then usually top soil is spread out, finally it can be monumented.?ÿ
This office will not start a subdivision unless the developer agrees to the final staking. Once dirt work and roads are done we go out and monument it, by then the plat's long been approved.?ÿ
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Pretty much the same, it's been 12 years and I'm not exactly young anymore, so I don't actually recall when we'd stake the lots, at least before houses were started. I was more responding to your final thought pertaining to the surveyor being responsible/liable for monuments that are stated on the plat.
That's the key, there should be original monuments from the platting surveyor. Why should you need to resurvey a Section line everytime you want to stake pins for a lot in a subdivision. It should be the near control of adjoining lots if pins are missing.
There are competing thoughts here that should be considered.
First, if measurements get me to the monument life is good. A few tenths may have been within the standard of care for the time.
The second thought is; Measurements aren't the end all but we should be able to do better with minimal effort. Dimensions in the record can become our only evidence in some cases. Why not do it right.
There is an insidious line of thinking that hurts the profession more than many realize. Many believe you can be capable of properly applying the law to boundaries OR you can measure well; but certainly not both. I am calling complete bull crap on that one..?ÿ
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Agreed.
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I'll?ÿ go one?ÿ step further (mind you I'm not licensed) and say minimum standards does not invoke minimum effort or care either.
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How about roughly four feet??ÿ I've worked off a certain quarter corner twice monumented with a half inch bar.?ÿ My guy calls this morning to say he has found a 5/8 bar but its about 3.4 south and a foot west of where the half inch should be.?ÿ No sounds, good or null, at my spot.?ÿ So, I go back through all my notes and find I had found the half inch based on KDOT notes and they had found and dismissed the 5/8 bar set by a specific surveyor at some time in the past but after KDOT had set the bar many years ago.?ÿ I now remember that I had one heck of a time finding the half inch back in 2015 only three months after KDOT had found it again.?ÿ Simply had to dig down through the gravel road about four inches before a signal appeared.
He also reported finding two bars at the northwest section corner about 18 inches apart, but, thanks to my references he landed on the correct bar.?ÿ That other bar was not there in 2015.?ÿ Don't know where it came from.?ÿ The bar I had used was referenced on work in 1989 and not nearly as shiny as the other one he found.
There is an insidious line of thinking that hurts the profession more than many realize. Many believe you can be capable of properly applying the law to boundaries OR you can measure well; but certainly not both. I am calling complete bull crap on that one..?ÿ
Yea, verily brother. I suspect that many of those that will argue that thinking are capable of neither good measurement nor reliably identifying the right point.?ÿ
Raise your hand if you have visited an NGS baseline in the past 12 months.?ÿ https://geodesy.noaa.gov/CBLINES/calibration.shtml ?ÿ
This is probably not the issue that the OP has but makes me wonder if anyone but me does this. The baseline at Sand Point here in Seattle gets overgrown between my visits that I have to ask for it to be cleared and they do.?ÿ?ÿ