When looking at a plat from the last 10 years, has the way that the subdividing surveyor determined North relative to their basis of bearing ever changed where you would replace a missing corner, using existing monuments?
This an honest question. I feel I am missing something in this basis of bearing discussion.
No. If I find a missing corner, assuming other monuments fit and check within reason, I am setting the corner at record distance and angle (bearing), turning the angle from the nearest monument, with that angle (bearing) calculated using the basis of bearing.
If that makes me a poor surveyor, I want to know it. Please correct me.
> When looking at a plat from the last 10 years, has the way that the subdividing surveyor determined North relative to their basis of bearing ever changed where you would replace a missing corner, using existing monuments?
Sure, of course. Why would it not? Do you never have to deal with situations where some subset of the boundary markers are of questionable stability? Between:
(a) utility and road construction,
(b) lot grading,
(c) foundation contractors driving 2x4's right next to a stake for a string line,
(d) fence builders,
(e) soil movements, and
(f) various other events,
it's a common task to to try to figure out which markers actually are original, undisturbed monuments shown on the original subdivision plat. Being able to independently reproduce the bearings of lines is a huge advantage.
> If that makes me a poor surveyor, I want to know it. Please correct me.
One minor question: Am I right in thinking that you actually aren't a surveyor, but are employed by one?
I am just as poor of surveyor as you are. I follow what's there. If the previous surveyor assumed bearings, so will I. If he used true or grid, that's what I use. If I am a left to my own devices I assume North or East.
Assumed bearings are a dependent system. Dependent on you finding two or more undisturbed monuments to reproduce the bearing system.
The advantage to true, grid, etc. is that they are independent systems. If you're left with one reliable point on the ground you can retrace the survey.
Steve
Replacing A Monument, A Part Of The Whole
No single monument has any greater dignity than any other, I read similar words on this board last night. You survey the parcel in it's entirety, best fit the record (I did not say LS adjust) and replace a lost monument by your best fit coordinate.
By simply occupying one monument, backsighting another and turning record angle and distance, you may be perpetuating or even exaggerating an error.
Paul in PA
In my opinion, when you are replacing a lost monument in a subduvision and you have all of the original undisturbed monuments and other evidence necessary to replace it, what the original surveyor used for basis of bearings doesn't matter. It's the relationship between the monuments that counts.
Replacing A Monument, A Part Of The Whole
> By simply occupying one monument, backsighting another and turning record angle and distance, you may be perpetuating or even exaggerating an error.
You seem to be suggesting surveyors cannot examine the problem in it's totality without an independent bearing system. I can shoot all the monuments/evidence with any bearing system and make sound judgements.
Steve
Heck yes! If it is on grid then I can just fire up my GPS and set 'em where she says to 😉
ahhh, but if you find it is it really missing??? 😉
Only in an extreme situation could I see the need for reproducing a subdivision bearing relation independent of monuments. Specifically - large lots with few corners, extensive construction of infrastructure and utilities after original stakeout (which as Kent mentions, disturb or destroy the original monuments), lots with monuments of varying character that don't agree with record calls and are not original.
In the first case, employing a reproducible bearing could be better than using found corners, particularly if the geometry isn't very good, such as using an existing baseline 100' long to turn in missing corners 500-1000 feet away. If the 100 foot baseline is off by a tenth of a foot in orientation, how far off will your new points be 500-1000' away?
In the case of the second and third instances, reproducing the bearings extrinsically could provide a quickly available independent piece of information that could allow a professional to rule out disturbed monuments or monuments that were reconstructed improperly. In the past several subdivisions we have done, utility installation contractors have set telephone and electric pedestal near our monuments often pulling them up and resetting them later +/- a foot from where we set them.
With practice, sunshots can be done in about 15 minutes, with a repeatability of less than 20 arc seconds, requiring very little in the way of extra equipment to what you already carry in your truck. I don't do them much anymore because we have other options available to us now with GPS, but even for those who don't own or have access to precision GPS, bearings can be reproduced quickly and precisely.
If we're talking about Honest questions, I think the more honest one is this.
IN the next ten years would you (or clients you have been retained by) like to be able to replace a missing monument using measurements provided by the original surveyor? Would this benefit clients in a way that the cost is reasonable?
I think in many areas municipalities have made the decision and require certain precision and bearing basis for new subdivision. Mostly to populate GIS for future public uses of the data. But this would theoretically also allow quick replacement of disturbed or missing monuments, or addition of new ones on line without the expense of scouring the entire subdivision for evidence in order to peice it together.
I think the public is starting to demand measurements that are as good as technology allows. I'm surprised I have not already seen a court case where a coordinate was held over a monument of arguable origin. I'm sure there is a case out there or in the near future.
The question that comes before dmyhill's question in the first post is "have you ever found a monument that you would not have found were not for a reproducible basis of bearing"?
This whole topic is silly
We, as surveyors, do our best to locate all the evidence we need to make ourselves comfortable with the project at hand. The relative location of multiple monuments and other forms of evidence lead us to a solution. One of the minor choices of influence in MY WORLD, MAYBE NOT YOUR WORLD is the bearing of any or all lines involved. Relative bearings, i.e., internal angles, may come into play, but, not always, because most of the time those internal angles aren't provided in the record. They are what they are.
> When looking at a plat from the last 10 years, has the way that the subdividing surveyor determined North relative to their basis of bearing ever changed where you would replace a missing corner, using existing monuments?
>
>
> This an honest question. I feel I am missing something in this basis of bearing discussion.
Not once in 20 years of surveying have I had to resort to using a "basis of bearing" as the sole evidence for finding a corner. All other evidence (excepting maybe acreage) has higher value than a "basis of bearing". Even if a corner is "lost", you nearly always need to have at least 2 or more corners to replace it.
No.
Replacing A Monument, A Part Of The Whole
I fully believe that a surveyor can examine the problem in its totality by looking at all the found monuments in relation to each other WITHOUT ANY FANCY GLOBAL DATUM STUFF.
Not only that, I believe that this is what a boundary surveyor DOES that makes them professional.
To dig up monuments, examine them in relation to other monuments, decide if they are original and undisturbed or a reasonably accurate perpetuation.
I say again, this is what makes a surveyor professional. Not precise measurements. Not placing the grid du jour on the ground. That is for technicians and bureaucrats, neither one of which has the knowledge or experience to look at found monuments in relation to each other and consider all the evidence, physical, parol, or written.
The global datum / astro bearing / grid stuff is great for recon.
And it is great for reporting stuff once you find it. Or maybe even finding it again someday. But remember that most of what boundary surveyors do is retracement, and most of the surveyors in whose footsteps we follow were using assumed bearings, relative angles, ground distances. and local monuments.
It is good to report what you find in modern terms (LLH, state plane coords, repeatable bearing basis, etc.), maybe it will help a fellow surveyor in the future.
There is a certain inertia about providing the more global/grid type info on a survey. This inertia is, I believe, rooted in the age old conflict between the self-reliant (at whatever level of organization, be it individual, family, village, tribe, or state) vs. the ever-growing collective bureaucracy.
One wants to know what it owns, in a local sense, relative to its neighbors.
The other wants to know what everyone owns, so it can tax the holdings.
My first mentor grinned like a cheshire cat one day when I complained to him "why can't these surveyors get their bearings to agree, and how come none of them match either the GLO notes or the GPS I just did?" and proceeded to explain the concept of "local report".
well, not exactly on point but I do recall a situation that might be similar. I was working in western michigan on cell tower sites and we had set irons on the boundary and prepared a plat of a new cell tower easement (I was not the LS in charge). The tie we showed on the plat was incorrect. Another surveyor hired to survey the easement for another cell phone provider (same tower and easement) called me and said that the tower and easement was in the wrong spot and he couldnt find any of the corners so he set them in the field. I returned to the site and found all the original corners we had set just outside the fenced in area around the site. after some discussion with the other surveyor, I discovered the bad tie. This surveyor had staked the easement based upon the grid tie, despite the fact that there was a 150 foot tall cell tower with fence and corners clearly marked around it. Talk about ignoring occupation!
rambleon
That is about the saddest story I've heard for a long time. Talk about a disgusting stain on our profession. It is too bad such stories appear far too often concerning our profession. Idiots of that kind are why some people think passing more rules, statutes, and regulations are the answer. No, pulling that idiots license is the only reasonable answer.
> One minor question: Am I right in thinking that you actually aren't a surveyor, but are employed by one?
That's more than a little impertinent.
My answer to dmyhill's question is no. It has not made any difference. Ever. It is the angles that are relevant, not the bearings. The bearing is just a convenient manner of notation.
Plenty of old plats have no bearings or angles noted at all. No problem. That is to say that it doesn't impede recovering the corners unless you intend to do it by running out the math off a couple of remote monuments. And, IMHO, that's not the proper way to do that sort of work.
