Some math for Kent
> I set the monuments in 2001 from a point west of the property. Then I moved the base to a control point north of the property and ran line checking the monuments as I went. No adjustments were applied. The coordinates are calculated positions of a section breakdown.
>
> The 2012 checks were done from the west control point.
Okay, I'm not quite sure I'm following that. When you set the monuments at some precomputed coordinates in 2001, what method did you use if you can recall? That is, were you chasing the stake-out coordinate in real time, or did you position some offset points that you set the markers from using their positions obtained by some method?
When you checked the positions of the monuments in 2012, what procedure did you use?
Some math for Kent
Stakeout to the point. Get the rover to the point, make a big hole with the point of the rod when I'm at the point. For these kind of points-drive a 30" aluminum power grip rod through the hole, grab a hack saw and saw off the top so the cap will corectly set on the rod. I take out an aluminum cap and invert a fence post driver agaisnt my 4 wheeler to set the 3-1/4" cap in. Stamp out the cap. Tamp the dirt around the rod until it's where I want it. Then pound the cap on the rod. Dump the rover and refix, then take a check shot on the cap. Whew!
By then I sweating (mainly from the hack saw) and I stack some rocks around the cap. No, I don't set offset nails for these kind of monuments. In urban areas or Highway right of way monuments I do.
Check the cap again from a different control point-no adjustments.
All the checks are to the precalculated number. The new plat is on a different projection so the bearings between the corners will be different, while the distances are very close (about .02' per mile at this location between the two projections).
Some math for Kent
> By then I sweating (mainly from the hack saw) and I stack some rocks around the cap. No, I don't set offset nails for these kind of monuments. In urban areas or Highway right of way monuments I do.
>
> Check the cap again from a different control point-no adjustments.
Okay, so if I'm finally understanding this, you set the rod and cap monument and then chased the coordinate down on the cap and set a punchmark (or cross) at that spot? Then you checked the punchmark (or cross) from some other base station set up but didn't add any of those vectors into the network adjustment to document the as-set positions of the rod and cap monuments?
While you're comparing the present positions of the rod and cap markers to the design coordinates where you were trying to set them in 2001, you do have a separate set of RTK vectors from which you can compute the as-set coordinates of the markers in 2001, right?
Just out of curiosity, why didn't you compare the actual 2001 as-set coordinates to 2012 as-found coordinates and give the uncertainties that the network adjustment estimated for both?
Some math for Kent
Just out of curiosity, why didn't you compare the actual 2001 as-set coordinates to 2012 as-found coordinates
I wasn't clear about that. These are the two coordinates compaired.
I did not adjust coordinate locations in 2001 nor will I adjust anything now.
I will hold record plat distances with a rotation to get on the new projection. But all angles between corners will be the same as in 2001.
All caps are stamped per the manual. Nothing else is added to the cap except a license #. No dots or crosses alowed. But I do know where the old shots were taken as there are lines and such on each cap.
Some math for Kent
> Just out of curiosity, why didn't you compare the actual 2001 as-set coordinates to 2012 as-found coordinates
>
> I wasn't clear about that. These are the two coordinates compaired.
>
> I did not adjust coordinate locations in 2001 nor will I adjust anything now.
Okay, so just to be perfectly clear, when you posted above:
>I set the monuments in 2001 from a point west of the property. Then I moved the base to a control point north of the property and ran line checking the monuments as I went. No adjustments were applied. The coordinates are calculated positions of a section breakdown.
what was meant was that the target or design coordinates of the monuments were some theoretical coordinates of the corners of the aliquot part, but you actually did log the as-set coordinates of some distinct reference mark on the cap? And you did log the as-set coordinates of the same caps from RTK vectors from a different base position at the same time? But - and here's the point I'm really asking about - you didn't include both sets of RTK vectors in the network adjustment in 2001 to get the as-set positions of the boundary markers?
What was your thinking there? Do you just never log RTK vectors with variances and covariances? Settling for just recording the coordinates that the system is indicating seems like you're throwing the useful part of the record away. Is there some other issue in play there that prevents bringing RTK vectors into the overall adjustment of the project?
Category 1-Beep Survey?
>Seems suitable for things like, for instance Cat 1-B Standard Survey in TX.
I believe you have a Category 1-Beep Survey in mind, don't you? That doesn't actually exist as a standard in Texas.
Some math for Kent
I adjust all the control-after that I don't adjust. I've always considered the RTK info too inferior to use in adjustments. I prefer to use static data for that. Maybe I should reconsider seeing how good this stuff came out.
Category 1-Note-Song Argument?
So you ridiculed other states standards as "shack survey" standards.
Then it is pointed out that even TX has a lower-level-accuracy standards for some surveys. Owned.
Then you have to resort to implying that I or anyone else advocates a one-beep RTK session. How sad or desperate.
What next?
Seems your crusade may not be winning them over(from this thread):
"Maybe I should reconsider seeing how good this stuff came out"
Some math for Kent
> I adjust all the control-after that I don't adjust. I've always considered the RTK info too inferior to use in adjustments.
I'd think that it's probably about the quality of PPK vectors of similar lengths. You use those, don't you? Probably the main trick is just figuring out what sort of a scalar is appropriate to correct the overly optimistic variances that may be logged if you're recording the full vector with the processor-estimated uncertainties, and dividing the GPS vectors into different groups or variance classes for different scalars.
> I prefer to use static data for that. Maybe I should reconsider seeing how good this stuff came out.
Well keep in mind that the very small sample you posted doesn't provide much of an assurance of anything. If you want to get serious, I'd think that you'd want to collect the full RTK vectors and add them to an overall adjustment properly weighted and do it regularly.
Naturally, redundant vectors at different times provide a basis for partially validating the weights assigned to the RTK vectors as would conventional measurements between nearby points positioned by RTK when added as a condition to the adjustment.
Category 1-Beep?
> So you ridiculed other states standards as "shack survey" standards.
> Then it is pointed out that even TX has a lower-level-accuracy standards for some surveys.
Did you actually bother to read the Texas standards? Hmmm?
Category 1-note-song?
Yes, and other tidbits a pal in TX pointed me at after reading the threads.
And more tidbits.
Texas Administrative Code §663.15. Precision
The actual relative location of corner monuments found or set within:
corporate limits of any cities in Texas shall be reported within a positional tolerance of 1:10,000 + 0.10'
extraterritorial jurisdiction (EJT) of any cities in Texas shall be reported within a positional tolerance of 1:7,500 + 0.10'
all rural areas outside extraterritorial jurisdiction areas of all cities in Texas shall be reported within a positional tolerance of 1:5,000 + 0.10'.
Must burn you up that even in Texas, RTK, properly utilized could meet published standards. Next I would expect that you are goin to claim that no RTK user levels thier inmstrument. Just kidding.
The crews that do oil lease work for us store vectors which are used in an adjustemnt that includes the static we also require.
Please continue your crusade, the math is educational, the rest is just entertaining when it is not insulting.
Category 1-Beep?
> Texas Administrative Code §663.15. Precision
> The actual relative location of corner monuments found or set within:
>
> corporate limits of any cities in Texas shall be reported within a positional tolerance of 1:10,000 + 0.10'
> extraterritorial jurisdiction (EJT) of any cities in Texas shall be reported within a positional tolerance of 1:7,500 + 0.10'
> all rural areas outside extraterritorial jurisdiction areas of all cities in Texas shall be reported within a positional tolerance of 1:5,000 + 0.10'.
>
> Must burn you up that even in Texas, RTK, properly utilized could meet published standards. Next I would expect that you are goin to claim that no RTK user levels thier inmstrument. Just kidding.
Actually, if you analyze that tolerance, you're left with an error budget that RTK will fail in many cases. What do you think the error budget is between marks 50 ft. apart if a relative positional error greater than 0.10 ft. is considered incompetent practice?
Category 1-B Texas Standard Survey
Yes, I am well aware of how that works. Short legs are problematic and even sometimes impractical for GPS, especially RTK/PPK. That has been acknowleged by many in the threads of past days. There are still a tremndous number of surveys that do not have such short legs and fall in the category of rural surveys even in TX to make one consider the proper use of RTK/PPK for them. And people do.
Like my example the other day. If the crews doing the surveys for oil lease work refused to use such tools and ran a many hour/day traverse ebcuaee they felt they had to provide much better precision than actually required, adding extra costs, then they would be so intelligent as to be out of a job.
Quibble about the short legs. The tools can be and are used in Texas without blowing the rural standards.
But I do wonder if they were placing a date on every page of the field book or not? I think that is very important.;-)
Category 1-Beep Survey?
"Category 1-beep" LOL. That is a good one.
Category 1-B Texas Standard Survey
> Yes, I am well aware of how that works. Short legs are problematic and even sometimes impractical for GPS, especially RTK/PPK. That has been acknowleged by many in the threads of past days.
Oh, so you're agreeing that RTK is highly problematic for cadastral surveys where the marks positioned are close together? Glad to hear it. That was - deja vu! - the point of departure of this weave of threads that you got so exercised about. :>
> There are still a tremndous number of surveys that do not have such short legs and fall in the category of rural surveys even in TX to make one consider the proper use of RTK/PPK for them. And people do.
So, uh, was anyone disputing that beyond the general point that without good quality control even easy stuff like that can get completely seduced?
> Like my example the other day. If the crews doing the surveys for oil lease work refused to use such tools and ran a many hour/day traverse ebcuaee they felt they had to provide much better precision than actually required, adding extra costs, then they would be so intelligent as to be out of a job.
Oh, so you discourage adequate quality control procedures? Why does this always seem to go hand-in-hand with RTK?
> Quibble about the short legs. The tools can be and are used in Texas without blowing the rural standards.
No, clearly you don't appreciate the point that unless you are actually awake to the implications of the very tight error budget when marks get close together, you're going to blow all of the Texas standards since the relative positional error will exceed the allowable threshold. Naturally, if you're sitting up in Canada somewhere, and don't have a Texas license, this won't bother you that much, right?
Category 1-Beep Survey?
> "Category 1-beep" LOL. That is a good one.
Yes, as in: "Category 1-Beep, Code Red RTK Survey". :>
Category 1-B Texas Standard Survey
Why do you have to do that?
Lie, flat out lie.
This is like those P&R threads where they have to make up stuff or put words in others mouths to make thier points
"Oh, so you discourage adequate quality control procedures? Why does this always seem to go hand-in-hand with RTK?"
What nakes you think there are not QC steps involved or that I discourage them?. You yourslf admit to adding PPK. We do the same and with RTK as well. The nice thing about RTK over PPK is we have a little feedback right then and there that something is up (if that is the case). We only use PPK when there is no radio or cell signal possible. We add the vectors, and we add static.
Kind of like those cable "news" channels, they vna make up stuff against people and just keep doing it and if there is not response they can claim it is true.
You are a real funny guy. Enjoy your little superiority-dance, I do not think it is justified.
Category 1-B Texas Standard Survey
> What nakes you think there are not QC steps involved or that I discourage them?.
Well, your suggestion that somehow doing what is necessary to meet a specification is somehow economically unfeasible has some direct implications for practice, doesn't it?
That and the conclusion that if you actually were doing rigorous QC you'd readily recognize the problems with RTK when I originally mentioned them instead of having to waste time arguing about something so obvious.
Category 1-B Texas Standard Survey
Flat out lie again.
I was talking about doing more than is neccesary, or doing more than required. As in more than the contract required, or the client is expecting to pay. There is big difference between meeting a standard and exceeding one, which can and does incur higher costs. You admit to using at least static GNSS, if there wereno cost differences then why not a clsoed traverse every time? What's a few miles or a few dozen miles added to that traverse, there is not cost differnce at all is there?;-)
Surveyors have to be good at business and meeeting their clients needs and specs and not just be good at (and be self-righteous about) math.
I recognized long ago that this is just another exercise like your old P&R threads (I did agree with some of those though) and I am just having fun now. I still doubt you have driven anyone away from RTK. Quite the contrary as we have seen in at least on instance.
Your turn. Or you can run and start another pontificating thread. Love the math, wish it didn't come with such a dose of attitude.
Category 1-B Texas Standard Survey
> I was talking about doing more than is neccesary, or doing more than required. As in more than the contract required, or the client is expecting to pay.
Okay, so you let what the client is expecting to pay dictate your QC procedures? That must be an adventure for whomever is professionally responsible for the work.