It's not like there isn't plenty of elementary survey texts out there. I've read a lot of them. I did miss the page where you need to pack a grinder along to relocate the previous punch marks to more accurate measurements. But hey, I live out in the wild lands. Nobody really gives a crap about a tenth or so. If they want my license for not tuning up a punch mark on a UDOT ROW marker they can have it!
Also, since you are right and there was a TDOT contractor equipment malfunction (or other consistent error) it's not to late. You have done your clients work and facilitated the sale. That's great! You can still contact TDOT and get the conflict cleared up (eliminate a pincushion). They should be able to require their contractor to correct the work if in error. It's sounds like their are a lot of these markers in the area.
What surprises me is that there was no discussion from the crowd that believes that the right of way gets its precise width regardless of where the original monuments staked it and/or error in the original survey.
The punch mark issue didn't seem (to me) that it would get so much attention.
I do not knot if this applies to the latest Leica instruments but there was an issue if you use non-leica prism with Leica instrument: you can not put offset specified on that prism in the Leica gun, you have to calculate it I uploaded Leica doc here
If prism says -30 - in Leica instrument you have to put +4.4. Nice trap eh ?
Hope someone may find it useful.
> But hey, I live out in the wild lands. Nobody really gives a crap about a tenth or so.
Yes, that's what I've understood is pretty much standard in Utah. An error of +/-0.5 ft. or worse probably doesn't bother you either. In Texas, however, it's expected that a surveyor can set monuments one heckuva lot better than that on a line a few hundred feet between corners. More importantly, in Texas there is no law that provides that boundaries are automatically shifted by an erroneously set marker such as the brass tablet I described. I assume that there is such a statute in Utah?
Another possibility is that one of the prism assemblies was used that allowed the prism to be screwed onto opposite sides, one correct for an offset setting of -30mm and the other for an offset setting of 0mm. If the prism was on the 0mm side and the instrument EDM was corrected for a -30mm offset prism, the net result would have been similar to what appears to have been done.
It's good to book instrument's PPM and prism corrections in the field book's Wx page headings, and to make sure the raw data collector file records it properly. This to spot gross errors as much as to show these sources of error were considered during the field measurements that day.
> It's good to book instrument's PPM and prism corrections in the field book's Wx page headings, and to make sure the raw data collector file records it properly. This to spot gross errors as much as to show these sources of error were considered during the field measurements that day.
That's certainly a good practice, but if you get in the habit of making a few redundant ties, the prism offset blunder should show up in neon letters in the least squares adjustment. Just a simple thing such as measuring to both control point forward and control point backward from a point nominally on a traverse line from which side ties are made will flag the blunder.
If you use resections at near 180deg angles between control points that you've measured the distance directly between, you likewise have a pretty sensitive test of the instrument offset since the sum of the resection distances will nominally differ from the direct distance by the offset error.
Naturally, even better practice is to add enough GPS vectors to a survey network adjustment. Those are efficient at picking out EDM blunders throughout the survey.
You going to contact TDOT about the errors?
> You going to contact TDOT about the errors?
The proper form of that question is: "Are you going to waste your time bringing the errors you describe to the attention of the right-of-way section in the local TxDOT office?" It's a question that answers itself when asked correctly.
Kinda reinforces my point doesn't it. Nobody except the anal surveyor really gives a crap about a tenth or so.
Are they going to build something exactly along this line? Something real costly to move? Is every square inch highly valuable? Who might question it?
Did you show the new buyer the punched up TDOT tablet to make him/her sure to use the right punch mark (by the T in Texas)?
I'm sure you did a grand job and don't doubt that it is correct. It gets a few miles around here. Other than that nobody really cares.
I get off on my own tangents. Got one going right now wasting my time to be sure it's right. In all actuality I could mark it anywhere within about 5 feet and the landowners wouldn't care or know any different. Sellers could care less where the boundary is as long as it doesn't slow the deal or reduce the sales price. I'm the only one that gives a crap! As far as the public is concerned I'm just another surveyor that can't measure the same as the last guy. They know this from past experience with surveys.
it very easy to make this error too: if prism constant is applied in the instrument and then once again it is applied in a datacollector, so it is applied twice to the measured distance.
Knowing that there are some folks who would tell you how "unprofessional" punching the second point is, I am going to jump in here and say -
Job well done!!!
Sounds like you found the original division line outside of the more recent DOT work and correctly monumented where it is on the cap with the second punch mark.
In the future, if many of those original monuments come up missing, your punch mark may be essential in projecting a point to the correct location for re-establishing the other corners of the lot in their original location. Depending on how long the line is, it could easily be several feet off based on the DOT point.
The description you will provide will clearly indicate what you did and why. Again -
excellent work.
>> excellent work.
Indeed. It's not often a surveyor charged with a lot survey in a platted subdivision from 1995 takes the time to tie down the whole subdivision with enough redundant observations to produce such a tight adjustment. Moreover, he either went out with the pre-plan of tying down the whole thing, or made several trips to add enough data to properly resolve found ambiguities in an ironclad manner.
I'm sure Kent's rigor will be appreciated by those who have to follow his footsteps in years to come.
The only questions I might have concern the excess in land area produced by the other previously mis-staked corners of the lot, and then the adjoiners after the lot in question was properly monumented by Kent. If our lot 'shrunk' in some staked dimensions and 'grew' in others versus the existing monumentation, then other parcels 'grew' and 'shrunk' commensurately wrt the existing mons. But I'd imagine that's a problem for another day...
