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
Yeah, I don't live or work where 1-2 tenths in 2650' matters much.
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.
