Basis of Bearings:
Geodetic North
Grid North
Assumed North
Taken from Previous Survey
From Deed
This is one item, that I feel is pivotal in the integration of our services, with the world, that is deserving of more time and attention, than it has gotten in times past.
I can remember performing all the field work, (via Transit and tape, or Total Station, etc) and finally coming down to the end, and asking my dad, "Dad, what basis of bearing are we going to use for the final presentation?" He'd tell me the East line of the previous survey for _____. Or the like. I'd rotate to that bearing, and publish that this was the basis of bearing.
There was a court case in NW Arkansas, where Jack Stiffler was involved. He became known as "Jack, Rotate-your-bearings, Stiffler", to the court. The attorneys were having a hay day with the fact his basis of bearings were not the same as some other survey. This illustrates the need to simplify for the general public this item. The Tax Assessors, and Title companies need to be able to work with this.
They often have no idea as to what a land survey is, and is not. Nor do they know the difference between "Putting the deed on the ground" or "Taking the the ground, and putting it on the plat". Or a mix and match of the 2 above concepts.
The fact is that almost all surveys are done "In GRID". That is, it is on a SINGLE RECTANGULAR system. If the plat says Basis of Bearings is Geodetic, or True north, then all that means is that at ONE place of that grid, it has been oriented to True north. As you move East, or West, it is NO LONGER on true north. That is only true, at one place on that survey, and on a radial line, from that point to the theoretical north pole.
When somebody publishes a plat, on True North, then they go and do a survey 1 mile to the east, (With another base station, and projection) and they both are on True North, then this means that they actually did a survey on two different Grids, wherein they were both oriented to the North Pole, at SOME POINT in their Grid. However, these two grids are not on the same bearings!
There is an exception to this. The BLM does their work on a semblance of a grid. They also use Least Squares, (Which is a really fine adjustment program). . Then, AFTER all decisions are made, ALL the individual lines are rotated, to be oriented to TRUE north. This was via an act of Congress!
Thus a line that reads N 89å¡12'W 80.01 chains, on one of their plats, would read S89å¡13'E 80.01 chains, IF it were labeled going East, instead of going West. Those BLM boys really freak out bearing systems, by this means. Because they round the bearings to the closest minute of arc. AND then they try to run the final rounded dimensions in a rectangular system computational device, to SEE IF IT CLOSES, after all that jacking around, to meet the Congressional standard! Sometimes they then ADJUST THINGS ONE MORE TIME, so that it will close, within min standards!
This leaves some slop on all the published values of the BLM. Needless slop. I wish they would PUBLISH it in ONE rectangular system, with a published theta, to convert it to TRUE north. Or to State Plane Grid North.
All this work, to meet an outdated standard.
And, MANY connoisseurs of RTK GPS publish plats "On true north". Yet, they do not know what just happened. That survey is ON TRUE bearings at the BASE station, and on a radial line to and from the north pole, at that point. Yet, they are working on a rectangular Grid, which is on TRUE at one location.
Then, they move their base station, and low and behold, it's NO LONGER on the same bearings! I had a surveyor, who is a real gentleman, and a decent guy, ask me WHY his bearings from A-B, did not match his bearings from B-A, when he moved his base. It took some work, but he got it.
Many folks have never bothered to ask, or even care to ask.
This is an illustration of the literal application of an outdated law, messing up a perfectly good survey. BTW, the BLM COULD publish two plats, one of them to meet the Congressional standard, and another that is on State Plane Grid bearings, to get rid of all that jacking around.
I am simply bringing it up, because it is a "Pivotal" (No pun intended, you know, Jack Rotate-your-bearings Stiffler) issue, at the junction of Land Surveyor, to Land USER. And, I feel that it should be addressed more directly. And, SIMPLIFIED for the general public.
I'd like to see legislation that REQUIRES all surveys in the State of Arkansas to be:
1.) On an objective* basis of bearings.
2.) Or referenced to an objective* basis of bearings.
* Objective Basis of Bearings means that the plat is oriented to State Plane Grid Bearings, or True bearings.
IF it is oriented to TRUE, then the LAT LON must be also published, where the sunshot, or GPS base was set. Or a Theta angle to Grid can be published.
If it is oriented to DEED, or previous Plat, then it has to have a THETA angle, or ROTATION angle published with it, to orient it to TRUE north, or State Plane Grid North. IF it is oriented to TRUE, then once again, the Lat Lon where the observation was taken must be published. Or the Additional Theta can be published to put it on State Plane Grid can be used.
This would make our work much more usable to all the general public, and remove some of the BASIC confusion that presently exists.
Surveyors who do not wish to learn to perform Sunshots (I've been doing them since maybe 1987) or to learn what is going on with their GPS, could learn it at continuing education. This would for a small amount of work, make the world of surveying more accessible to the general public.
Make the world a better place.
Nate
Get your lead state agency to do what Oregon did with OCRS. Have them use Michael Dennis's criminally inexpensive LDP Design software to do so. Voila! Georeferenced surveys with "ground" distances, all oriented to a projected basis of bearing.
"Nate the, Rotate-your-bearings, Surveyor"
Some comments:
1. Current measuring equipment provides greater positional accuracy than state plane coordinate systems are capable of reproducing.
2. Too many surveyors do not understand the state plane coordinate system
3. There is no such thing as "True North." Where is "False North?"
4. The earth wobbles on its axis.
5. Plate tectonics results in positional changes.
6. Directional references, ie basis for bearings, are always subjective --never objective. Someone, the subject, always predefines the reference direction.
7. A directional reference is implied when the direction between two points is identified. A directional reference does not have to be "explicit" as is in the case of a basis for bearings statement.
If a surveyor obtains a plat that does not include an explicit directional reference but, there are several monuments identified along with accurate directions and distances dimensioned among them, can he or she locate all the monuments after two are found? Does it matter where or what "north" is? Does it matter whether directions are based upon some "grid?"
As for dealing with the layman, taxman, title person, lawyer, etc, there is one fundamental problem with two parts: 1) how well can the surveyor explain the directional reference; and 2) how well can the listener comprehend and understand the concept. Until these two issues are resolved, it matters not what the directional reference is or how it is defined. I don't think this problem will ever be without us.
MLSchumann, post: 340200, member: 471 wrote: "Nate the, Rotate-your-bearings, Surveyor"
Some comments:
1. Current measuring equipment provides greater positional accuracy than state plane coordinate systems are capable of reproducing.
2. Too many surveyors do not understand the state plane coordinate system
3. There is no such thing as "True North." Where is "False North?"
4. The earth wobbles on its axis.
5. Plate tectonics results in positional changes.
6. Directional references, ie basis for bearings, are always subjective --never objective. Someone, the subject, always predefines the reference direction.
7. A directional reference is implied when the direction between two points is identified. A directional reference does not have to be "explicit" as is in the case of a basis for bearings statement.If a surveyor obtains a plat that does not include an explicit directional reference but, there are several monuments identified along with accurate directions and distances dimensioned among them, can he or she locate all the monuments after two are found? Does it matter where or what "north" is? Does it matter whether directions are based upon some "grid?"
As for dealing with the layman, taxman, title person, lawyer, etc, there is one fundamental problem with two parts: 1) how well can the surveyor explain the directional reference; and 2) how well can the listener comprehend and understand the concept. Until these two issues are resolved, it matters not what the directional reference is or how it is defined. I don't think this problem will ever be without us.
Good post.
I personally believe this "basis of bearing crisis" is way, way, way over-rated. I've yet had to fall all the way down the ladder of evidence and use a "basis of bearing" to retrace any survey - and I doubt I'll ever need to. As long as we are using, and continue to use monuments and evidence on the ground, the basis of bearing is basically irrelevant in finding the boundaries. As a profession, we have many bigger fishes to fry - lets not encourage the legislatures, governors, licensing boards, or even state societies to waste time trying to define and/or further regulate a mere basis of bearing statement.
We surveyors can deal with it. That is not the point. I have just run into a survey, where a pretty good surveyor surveyed the perimeter. Then, the client (loballin fool) hired this dude with survey license, and he proceeded to to survey out lots, and they did not use the pretty good surveyor's basis of brngs, or ANYTHING. Goof ball surveying. They also ran over lines of title....
N
A sound Basis of Bearing will aid in the recovery of monuments. It can reduce the maintenance costs for future owners. In short, a properly selected and documented Basis of Bearing is part of our Professional duty.
The GLO practices may not fit the ideas many hold dear, but the system is pure genius. The dignity of monuments, accessories and the earned rights of entry men is no accident. Having all of my jobs on grid means following directions is only a convergence angle away. If a few minutes of angle don't get me close enough to observe the actions of owners I'm in trouble.
I respect you Nate and this isn't to bash you. Yes we should be able to be followed, but the retracing Surveyor shouldn't miss my footprints looking for seconds...
We have large areas now, in Arkansas, where the BLM did not set monuments. They are just computed. Goes for miles. There are ties to stuff they rejected, but thats about it. Closest Link. (so that would maybe be 1/2 link, due to rounding) It just makes for the possibility of One perfectly good survey marker, set a few tenths off, one direction, and then if the mon gets disturbed, then another perfectly good monument being set one foot away from the previous one. BLM is setting sparse monuments.
"Basis of bearings, true north, taken at central meridian, State of Arkansas"
😉
(Looked around a bit)?ÿ Thataway's North!
(Looked around a bit)?ÿ Thataway's North!
I've looked hard and can't find the decades-old Tumbleweeds comic where the cowpoke asks how the Indian knows where north is and the reply is "It just looks kinda northy over there."
I have a 1970 Dependent Resurvey. Knowing what I know and having tied in a bunch of monuments I tried converting all the BLM bearings to State Plane grid at their midpoint then calculating the closure again, it got worse. It feels like the Cadastral Surveyor maybe rotated a line the wrong way. I gave up at that point, wasn??t that important.
A prudent man concealeth knowledge; but the heart of fools proclaimeth foolishness ...
?ÿ
Easy does it mark.
You aren't licensed here...,.
😉
N
He'd tell me the East line of the previous survey for _____.
The numbers on the map or the line between mons?
?ÿ
The fact is that almost all surveys are done "In GRID". That is, it is on a SINGLE RECTANGULAR system. If the plat says Basis of Bearings is Geodetic, or True north, then all that means is that at ONE place of that grid, it has been oriented to True north. As you move East, or West, it is NO LONGER on true north. That is only true, at one place on that survey, and on a radial line, from that point to the theoretical north pole.
When somebody publishes a plat, on True North, then they go and do a survey 1 mile to the east, (With another base station, and projection) and they both are on True North, then this means that they actually did a survey on two different Grids, wherein they were both oriented to the North Pole, at SOME POINT in their Grid. However, these two grids are not on the same bearings!
There is an exception to this. The BLM does their work on a semblance of a grid. They also use Least Squares, (Which is a really fine adjustment program). . Then, AFTER all decisions are made, ALL the individual lines are rotated, to be oriented to TRUE north. This was via an act of Congress!
Thus a line that reads N 89?ø12'W 80.01 chains, on one of their plats, would read S89?ø13'E 80.01 chains, IF it were labeled going East, instead of going West. Those BLM boys really freak out bearing systems, by this means. Because they round the bearings to the closest minute of arc. AND then they try to run .
Nate
Its amazing how many people accuse the BLM of surveys that don't close. A BLM survey, or, at least is theorey, a survey stamped as a CFedS survey will not close if you draw out the bearings and distances on a grid. Of course the "misclosure" will be much higher in Alaska than in Florida.?ÿ
?ÿ
