Moe
"You don't want to use a pipe wrench to assemble furniture and no GPS for concrete."
Now that there says alot.
N
Levi
I do imagine I'm working with some concrete crews that are really anal compared with what you experience. One guy that does quite a bit of it locally spends much of his time correcting surveyors that are really sloppy. I think he's happy when we show up on site, but he's awful grouchy so it's hard to tell.
I'm not really concerned with .04' ruining a job or being too far out. What I want are the checks that "prove" to me and to someone else that the points were set correctly and it isn't my stakes that caused a puddle in the gutter. It lets me sleep at night and that's worth a lot.
I'm certainly no expert on RTN's; there isn't one anywhere near my work. But, I do know that GPS users were trained on the older units to "calibrate" pretty much everything. It didn't take long for me to stop doing it and use other methods. I suppose if you are using an RTN and merging the RTN to prexisting control then there's no choice but to do it.
It sounds like you are paying close attention. Just asking the questions you are shows that.
Me, I'm an old guy who's battled contractors for 30+ years and wants to do everything as redundant as possible to keep them away frome me.;-)
> I've had nothing but success with it. I check in before, during and after staking. It's the wrong tool in the wrong operators hands.
Levi,
that's what everyone says when they stake and check with the same tools.
Once you "localize" there is no use of the geoid files.. It has to be one or the other.
And yes, using ONE point for vertical is the way to go in that case. Mathematically, using three will always result in a 'perfect' plane. Four or more will tilt the plane and that may or may not work.
You won't know until it's checked by a method MORE PRECISE than the one you used to lay it out.
Good luck. I'm with the others that say NO to any grading of solid materials with RTK. It's just too risky.
Andy
Levi
You are right about not having a choice to calibrate. Our company pays for a subscription to a network, and I would not know how to go about changing a base height like some have suggested. I've been with my company almost ten years now, and they have been laying out apartment sites in the area for twenty. We have a great reputation with the small collective of subs that do this kind of work. The last thing I would want to do is mess that up because as you know, reputation is everything in this industry. I guess what I'm trying to convey to some is that you only have to be as accurate as the job at hand dictates. If there are a few handicapped parking spots in the job, get out a level and grade those certain stakes. God knows It makes me sleep better at night. But when you have a couple thousand linear feet of curb, there's no need to beat it to death because a couple of hundred has to be nats ass. Like I've heard many times from people smarter than me, GPS is another tool in our box, not a magic wand.