Chew on this

First and foremost; make effin sure you're right.

Then, as cool and calm as you can, present the facts as you have found them.

There will be a solution, it's just; how much extra will it cost and who will pay for it....

>
> Any thoughts or advice?

First off - convert all of those inches to decimal feet. B-)

What Radar said.

Before ANYTHING make damn sure EVERYONE knows which datum you are using and document it with all parties signatures thereon. These kind of things can turn around and bite you on the ass before you know it.

Have a great weekend! B-)

Does not sound that bad really.
Typical engineering that the surveyors have to work out the fit in the field.
Just extend a horizontal curve a little here and rework a vertical curve there and you are on target.
Of course I would never have let them leave the other station and come my way.
It would have been better in my opinion to tie into their stuff at their station and make the minor adjustments along the way.
It is never a perfect world and you will find a way to make this work.

> Does not sound that bad really.
> Typical engineering that the surveyors have to work out the fit in the field.
> Just extend a horizontal curve a little here and rework a vertical curve there and you are on target.
> Of course I would never have let them leave the other station and come my way.
> It would have been better in my opinion to tie into their stuff at their station and make the minor adjustments along the way.
> It is never a perfect world and you will find a way to make this work.

I can rig it with the best of them. Its not the way I wanted to start a 400M job though. More to think about, we did the existing line and station. That project has been ongoing for three years. That control is tight and is monitored by the third party surveyor that set it for us. Kind of the same situation, they had provided the owner the owner provided control so we hired them to do the control network on that phase. I am familiar with that outfit and am confident in what they have. I transferred here when this next phase was awarded,the first thing I did was get the provided control to see how it fit with what we had going. It hit good horizontaly but there was a .25' vertical difference. We stopped down, called a meeting with everyone involved, got the ok to proceed on the first first bridge using the existings control, because the first bridge was too close to the tie in to wiggle much. The new surveyor for this phase, all of this time was confident that he could make it all fit in the new network, but it would take six weeks. At that time I suspected that what was "wrong" were the elevations on the conrtrol he provided the owner and that he would massage it out over the five miles. When I got the new data earlier this week, the levations on all of his original points had changed .16' to .25'. I thought aha! just as I thought. Our quantities are going to change and we might have to eat the extra dirt just for harmonies sake, but that is for the higherups to decide. I am ok with the elevations they provided because now they match what we are using and what the other people that are building the tie in station are using. They gave me data on 50 high security monuments as well as on their original 15 monuments. We go out and calibrate on their originals with the new data and start doing some checks. Thats when I notice that we arent hitting anything within 2 inches horizontaly.My first instinct tells me to check myself so I do, nothing seems to be amiss. We broke out the robot thinking it could just be GPS demons and found that the new points not only didnt tie to the existing control, but didnt fit real well initself.Then I check the data and find that the NE's had changed on not only his original points but also the existing control that he threw into the mix. Therin lies my problem. That and also the owner has very tight tolerances and their own third party firm to come in behind auditng us to make sure we meet them.

Few years back, working on a survey of a river corridor in a National Park, one crew (me as LS PC) and the project manager, who was an EIT who was good at baffling his bosses with BS and impressed them because he knoew how to operate a scanner.

EIT was provided an office in one of the Park bldgs and was providing on-site support for the field crew by, um... by... I don't really know wtf he did most of the time other than trying to pick up on the teenage office assistant down the hall.

We had run about 4 miles of control for topo, 2 mi upstream on one side, 2 mi downstream on the other and in to close. Also made several ties across river between control points to brace the figure & tighten up the adjustment. Field coords carried showed a misclosure of 3 or 4 tenths - pretty good considering that there were many short legs and some over swampy ground.

Whiz kid EIT plugs it into a program he was somewhat familiar with and supposedly performs a least squares adjustment.

We go out the next week and begin topo. All the way around, we have BS distance checks and FS check shots of +/- 0.01' to 0.03'. I was expecting just a bit more variance between field distance and adjusted distance given the closure, but OK, no alarms yet. Then we get to the station just before the trav POB. BS check, like all the rest, a hundredth or two, but the FS check shot - about 1.5'!

I have the I-man turn inst away and turn back. Same result. I have him recheck BS and turn stakeout. Meanwhile I go to FS to see if maybe there are 2 mons close together - nope, right mon, undisturbed. I go back to inst station and similarly check it - looks good. Same with BS. Stakeout info shows a distance about 1.5' off from our initially measured field distance!

So I call the OIT on the radio and let him know what we've found and ask him to check his input. Rather than a "I'll check & get back to you" response, the EIT with 5 years experience begins to lecture the LS with about 25 years experience over the radio about how least squares adjustments work in terms my chainmen were able to recognize as total BS. They thought it was hilarious as I contemplated whether anyone would really miss the EIT if I hid the body really well. The knucklehead was so used to people accepting his lines of BS that he didn't even stop to consider that he was trying to BS someone with vastly more training and experience on the subject.

Short moral of the story: Find someone in the surveyor's office with enough sense to know that just because a computer spits it out to 8 decimal places, that doesn't necessarily mean the data is valid, and also has enough knowledge to properly review the control notes, entry, and adjustment for valid input and valid results.

If the control in the middle isn't valid to the control at either end, there may be some leg within the new control that makes it not valid within itself. Better to get to the root now than later finding that you need to blend in a vertical discrepancy that will be noticeable in the finished product.