Two engineering companies establish control at a rather (for this area) large complex of buildings. Company 1 hands us a control spreadsheet with metadata. We are helping out with the topo cause they are in a rush and are busy.
Set up on a control point, check into another-.25' off vertically, .1' horizontally. Seems there are two sets of control, one by Company 1 and another later set by Company 2. So we tell Company 1 about the "shift", they say just adjust to their set. Ok, but what about all the topo you are going to tie into? That's why we are there, the topo got partly finished (all the utilities) and now they decided to complete the project with surface features (don't ask it never made sense to me).
Seems there was a set of control run in using Geiod03 (Company 1) and tied to local cors. Then a set run in with an OPUS solution (maybe) and Geoid09 (Company 2). Not sure if bench marks were used at all. SIGH!!!
The .1' horizontal is probably the difference between epochs (difficult to really tell that one) and the .25' is consistent with the Geiod shift. So just what is tied already form where? I have no Idea, all I can do is let them know about the problem.
I will just keep saying NOT MY PROJECT-NOT MY PROBLEM!!!:-X
In the old days this wouldn't happen, establish control and stick to it!!!:-@
I'm working on a rail layout project where the engineer's provided control on the plan set. The project includes two crossing separated by about 1300 feet. The control provided was a base line about 400 feet in length at one of the crossings. The points were a small PK nail and a concrete nail both set over four years ago. After searching for a couple of hours I was able to find the concrete nail and the hole where the PK had been plowed out. They fit within 0.02 feet. Went to check the existing rail center line and found it to be 0.95 off opposite the back sight and 2.25 off at the instrument. Okay, that is not going to work. Final track down some additional control from the prior surveyor. Run about a mile of traverse and find the control points the engineer provided off by over 7 feet. Low and behold my physical shots fit the plan center line when I used my new control values. Only took 10 hours to find the control, realize that it was bogus and then run in new control. I had about 10 hours to layout both crossings. So much for their budget, at least the contractor is willing to pay the extra.
Don't you just love it!!
It seems to happen more and more these days, control is IMPORTANT!!!!
Leave some good monuments, put good metadata on your survey/report/plans.
And stick to the same control all the way through the project. WHY IS THAT SO DIFFICULT????:bored:
Had a job in Norman early last year for 2 miles of road improvements. There were 2 survey groups on the team. One was to establish control and tie boundary. The road centerline followed the section line. The second team was to topo the road.
I did the control (establishing monuments every few hundred feet along the alignment for topo control), StarNet adjusted, prepared a detailed report and map I including adjustment report), and submitted to the topo consultant and project manager. A few days later I observed their crew set up over a control monument that was 20 feet from one of mine (mine still had a well flagged lath marking it). I stopped and let the PC know that I had established control, got his email, and forwarded pdfs of my report and map direct to the PC and cc'd his manager, who had already been sent a copy. I discussed this with my manager and the project manager and followed up with detailed emails expressing my concern that this needless duplication of effort was not only costing money but was bound to lead to problems later. All this within 2 weeks of NTP. The topo crew continued on with setting their own control, all of them within feet of mine.
I proceeded to file CCRs on the PLSS (aka centerline) monuments, with SP coordinates.
A year later my manager forwards a frantic email from the project manager wanting to know why the topo company's coordinates for the centerline don't exactly match the CCRs I've recorded (differences in the 0.02' to 0.1' range). I forward old emails and that's the last I hear of it. But it still bugs me. That's OK.
yep, seeing this kinda stuff more often now, no time being put into fixing control, it's odd:-(
> I did the control (establishing monuments every few hundred feet along the alignment for topo control), StarNet adjusted, prepared a detailed report and map I including adjustment report), and submitted to the topo consultant and project manager. A few days later I observed their crew set up over a control monument that was 20 feet from one of mine (mine still had a well flagged lath marking it).
I'm going to guess that the underlying problem was that the folks doing the topo didn't have the capability to do anything meaningful with the Star*Net adjustment you provided. Otherwise, it would have been ridiculously easy for them to have taken your Star*Net file and just ... added the topo measurements to it and rerun the adjustment to generate the topo coordinates.
Any problems with the control would, of course, have shown up when the new measurements were combined with the GPS network. If the network were free of blunders (as I'd bet it was), then the combination of the GPS and conventional would have been an even further refinement.
Yes star net would help, only it's two different companies, company 1 doesn't have data from company 2, it's a jumble of points in a coordinate file, I am turning over adjusted control from company 2 to company 1 and they will have to sort out the points.
It looks like a subtraction of the elevations (the most important shift) and a slight move for the horizontals.
It was very consistent, no rotation (a few seconds) and .25'-.28' vertically.
Some checks in the field and should be good to go.:-)
> Yes star net would help, only it's two different companies, company 1 doesn't have data from company 2, it's a jumble of points in a coordinate file, I am turning over adjusted control from company 2 to company 1 and they will have to sort out the points.
I was thinking more about the case that Norman mentioned, but in either case, on a project where survey measurements by various folks are to be combined, it would be too easy just to specify that it all has to be delivered in the form of a Star*Net adjustment file, both for Q/A purposes as well as for consistency.
These kind of threads remind me of why I liked the world better in the 70's when it was flat.
Best of luck 😉
"These kind of threads remind me of why I liked the world better in the 70's when it was flat."
"The mission of the Flat Earth Society is to promote and initiate discussion of Flat Earth theory as well as archive Flat Earth literature."
Seriously, we are doing our best to keep it flat. I recently told an engineer that I would not convert our coordinate shots on a ±20-acre topo survey of an existing wastewater treatment plant site to grid. He was astounded at that answer, but after a few minutes of education said he understood, and was going to stop asking for them in the future.
> I'm going to guess that the underlying problem was that the folks doing the topo didn't have the capability to do anything meaningful with the Star*Net adjustment you provided. ....
They ignored my work. I expected them to simply use the control coordinates I provided. They should not have been tying boundary marks at all, except perhaps as routine checks. It must have cost them a lot of money. There are all sorts of ways they could have used StarNet but I think it likely that I had the only copy of that software that existed in the state.
> There are all sorts of ways they could have used StarNet but I think it likely that I had the only copy of that software that existed in the state.
LOL! I forgot this was set North of the Red River.
No doubt Norman was in the same situation, not having the underlying data to make star net of much use. Can't adjust data you don't have or inject it into a project you aren't in control of. Sounds like he already provided adjusted control.
> No doubt Norman was in the same situation, not having the underlying data to make star net of much use. Can't adjust data you don't have or inject it into a project you aren't in control of.
I was thinking about what a bright idea it would have been to have required the deliverables for the project to include the survey data (GPS vectors and conventional measurements) in Star*Net format. Since Star*Net is independent of some manufacturer's proprietary format, the different surveying firms could continue to use whatever flavor of hardware they wanted.
> I was thinking about what a bright idea it would have been to have required the deliverables for the project to include the survey data (GPS vectors and conventional measurements) in Star*Net format. Since Star*Net is independent of some manufacturer's proprietary format, the different surveying firms could continue to use whatever flavor of hardware they wanted.
This project of mine was a public works project, with the various team members having defined responsibilities. My responsibility was to establish project control and boundary. The other consultants responsibility was topographic mapping. They should have used the control I established to do it. That was the intention. All they needed for that from me was a PNEZD csv file. They got that and much more. Using that they could have used with any software they had at their disposal including just downloading the csv of the collected topo points from their data collectors.
Nobody ever questioned my control. Nobody -other than me- checked it. They simply ignored it's existence until a year later. If they had checked it I'm confident they would have found the same minimal residuals that were shown in my adjustment report.
I long ago established a control report format which includes a narrative statement of procedures followed, equipment used, held control, datums, etc., a spread sheet listing of the final coordinates in both geographic and SP coordinates - with detailed descriptions of the monuments, the StarNet adjustment report, prints of the raw data and field notes, prints of control data sheets, and a map or sketch of the layout. All wrapped up in a single pdf file for convenience. These reports run from about 20 pages for the simplest of jobs to well over a hundred for more complex jobs.
You can lead a horse to water, but you can't make it drink.
You can lead a horse to water, but you can't make it drink.
Yep, been seeing it a lot, everybody doing his own control, really dumb actually!!!
Control fun partial hijack
Recently we were doing a GPS project and were out looking for NGS control points to use. We found a BM that was close to our project and had been recovered in the last 10 years, and another one very nearby that had been used in a height mod project a few years back. The old BM was RV24 PID FF1208. The height mod point was RV24X DF7972. We went out to recon, and looked for RV24X first thinking that RV24 was probably gone. RV24X is near the end of a culvert head wall on the railroad. We found it with no problem. Then we looked at the center of the head wall and there was RV24. RV24 is a second order point and RV24X is a third order reset that was used in a height mod survey. Both were equally suitable for GPS observations. We used RV24 in our survey. We had to be real careful to send people to that point that would get on the correct point. We had them take pictures of the monument they set on every time. The 2 points are less than 1 mener apart.
