Activity Feed › Discussion Forums › Strictly Surveying › I could see the fumes
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Girls!!! You’re both pretty!
I totally agree an completely independent check is absolutely the best check to make. The worst mistake I saw happen, had to do with an error in the original control network and the next survey calibrating to the original control without any independent measurement checks.
Frankly, I think the original complaint in this thread was that the second surveyor was simply getting different coordinate values on the original control and stating that it was bad. I am thinking that Might-M understands how to check than the construction surveyor.
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I remember, back in 1975; we got a brand new chain (steel tape) and were doing some lay out when we checked into a known point and missed it by a few feet? We checked the distances 3 times and it kept coming up wrong. Another crew was working in the same plat, so we told them; when they got their chain out and checked the points we had layed out, they were off a foot?
Come to find out; the brand new chain had the 3ft and 4ft mark on top of each other. The tool was bogus, out of the factory. It took an an older tool of the same caliber, to find the error.
It’s a good thing MightyMoe collected the original datum with somethng that is reprducible, with the right metadata…:>
Accurate Regards
Doug Casement, PLS Puyallup
I hope everyone has a great day; I know I will! -
Welcome to the Thread
I’ve often thought that if you waited long enough, Kent would end up arguing with himself and the thread would end;Me thinks that this might be the thread;)
I hope everyone has a great day; I know I will! -
From my construction standpoint, there are obviously too many surveyors on this project!
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This is comical, to my recollection the only thread longer than this one was Bill McComber’s Eulogy thread on the old RPLS.com. About 13 or 14 years ago.
LMFAO 😀
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By the time this thread dies they’ll be repaving the highway.
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They were going to start moving dirt, but all the ROW monuments need to be shifted, highway redesigned, volumes recalculated to match the new coordinates 😉
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if it’ll help, we could just move the center of the Earth over a little. How much do you need?
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At the risk of making this post so long it blows up Internet
> So the guy goes out and sets on a few control points, sends his data to OPUS, and when the OPUS coordinates on those points do not match plan coordinates, he says the control is “unusable” and it needs to be changed so it will “match”. Agree or disagree with him?
It is entirely possible to identify a control network that is so bad that requires fixing by a few points sampled across the network. That should be obvious. If by simple translation, rotation, and scale transformation, the horizontal components cannot be brought into nominal congruency, that is significant evidence of a problem. If the scale and rotation are quite different than what they are reported to be, then that is strong evidence that the effort that produced the control network is flawed.
In this case, the control network control point coordinates in a bastardized coordinate system are to be used to lay out construction in locations determined by the plans in the same bastardized system. So it really does matter that the project control network not have certain problems and if it does, it’s entirely professional for a surveyor to say that the network can’t be used for layout until the full extent of the problems are known.
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At the risk of making this post so long it blows up Internet
Well, it took my crew (one man crew) 1-1/2 days to go through the entire network checking and also locating some existing ROW monuments. Because we weren’t checking for elevations (although we looked at them and didn’t find any errors) we didn’t need to run levels which would have taken another long, long day and two guys.
No doubt you would still have been OPUSing existing control and pointlessly shifting coordinates, subtracting and adding numbers to find some translation while my crew was out working on the job.
Sometimes you need to put on your big boy pants, accept that other surveyors are really good at what they do, get western and get to work. 🙂
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This thread has lasted so long that even i am replying. Moe, I grok you, brother.
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Reminds me of in a gadda da vida…
5% great
95% crap -
Almost as long as the reproducible bearing thread awhile back.
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At the risk of making this post so long it blows up Internet
> No doubt you would still have been OPUSing existing control and pointlessly shifting coordinates, subtracting and adding numbers to find some translation while my crew was out working on the job.
Obviously you haven’t understood that the OPUS solutions would give latitudes, longitudes and ellipsoid height of known accuracy for the base receiver positions so that all GPS vectors surveyed from them would be free of any systematic bias from using a jacked, unchecked value. Thats about as simple as it gets. If you want to be super meticulous, you’d substitute the ITRF08 Lat, Long, and EllHgt that OPUS delivers. You’ll get better quality, more accurate vectors, but that probably won’t be highly significant over distances <10km.
Then, you’ll need to give the data to someone who knows how to compare bastardized coordinates to actual survey coordinates if you don’t know how to do it. Simply computing the transformation parameters and listing residuals between SYSTEM1 and SYSTEM2(transformed) is pretty straight forward. If the bastardized coordinates were actually produced as claimed, the systematic azimuth between coordinate systems should be under 00’00.1″. If the bastardized coordinates are jacked, the azimuth bias will be larger and possibly considerably larger. Roughly the same for the scale differences between bastardized system and actual. Voila! You completed an important first check!
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At the risk of making this post so long it blows up Internet
I already had known values because they are fixed for the project and can’t be changed. Verified them and went to work. Got it done!! Life is good, project is done and filed. Control was fantastic. Didn’t use or need OPUS. 😉
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Stop it right now
I think you were addressing MM, Don. The idiotic non-OPUS side of this thread is like somebody claiming that if the control network was surveyed in local coordinates with a transit and tape, you’d really mess things up if you checked it in State Plane Coordinates with a total station, and if you surveyed the control network in State Plane Coordinates with a total station, you’re really mess things up if you checked it with GPS. None of them make any sense, really except from the standpoint of being on the losing end of a real check.
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Lets hope they finish the highway before NGS releases its next readjustment:-D
PLS NJ & NY, PP NJ
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