From the post a few days ago, I am wondering if anyone who has reestablished quarter corners on east-west lines has ever shown the curve data on the plat? Or are lines of latitude the only true straight lines to begin with? Is offsetting the quarter corner really offsetting from a straight line between section corners or is the curved line the straight line and there is no offset? If the curved line of latitude is staright, then there is no difference in bearings going east and west from the quarter corner even though a calculation was made to place it off line as our eye would sight between the section corners. 😉
Oh boy.............
Who's on first?
Curve data??
Like, curve to the right, L=2640 ft, R=15,800,000 ft ?
At the sixteenth corner, it would make what, 0.04 difference?
ya right!
Instructions?
Fourth. That the center lines of a regular section are to be straight, running from the quarter-section corner on one boundary of the section to the corresponding corner on the opposite section line.:stakeout:
Instructions?
You do understand what a geodetic straight line is, correct?
I recently completed surveys of parts of two Townships using the three-mile method which were then used for the BLM to prepare supplemental plats for the creation of new lots. I was instructed by the BLM Surveyor reviewing my work to place all corners, including the sixteenth corners on the latitudinal arc. This was easily accomplished by prorating the latitude and longitude coordinates and I think it made perfect sense. However, I don't think the old GLO surveyors would have made any adjustments as the adjustments are listed in the Red Book to the nearest link and in my area are less than 1 link for half mile intervals.
It seems to me like, if they were using a solar transit to run their "line", it runs the line on an arc. It doesn't have to take any links into account as far as I know. If they used angles, you can calculate the adjustment in bearings as you run your angles with the red book. (Maybe I am missing something. I am not an expert in this)
The law and instructions.
To put this all in perspective, we should realize how laws come about and are enacted into practice.
Statute law is written by bureaucrats in Congress and usually with the coordination with bureaucrats in the Executive Branch, in order to have understandable and doable law and regulation.
Hopefully, this results in good Statute Law.
The Statute Law that pertains to surveys/resurveys for instance, is then interpreted by the Land Department and regulations and instructions are issued to implement the law. That Land Department was the GLO and now the BLM.
It would seem to be obvious that the Statute Law would not get into the actual mathematics of running a "straight line" and that the term "straight line" would be proper terminology in the law. It then becomes the responsibility of the Land Department to implement this law into instructions to their land surveyors.
One can only imagine that the Statute Law in 43 USC 751, coould not have been written by a Senator or Congressman and would need help. That help would be in the form of bureaucrats in Congress and bureaucrats in the Executive Branch.
The Statute Law has been interpreted into instructions, (Manuals of Survey Instructions) and the 2009 Manual clearly explains how east-west lines are to be run on the ground and especially the east-west center line of a section.
There is no doubt in my mind, that my field procedures were the same in principle as my predecessors in GLO and BLM and that is how to run an east-west line on a curved line in the PLSS.
It seems to me that it is time for everybody to recognize that east-west lines in the PLSS are curved lines.
Keith
“Or are lines of latitude the only true straight lines to begin with?”
That’s a good question, Jerry. It all depends on what phase the moon is in. If it is in Phases 573.544g through 1-966.04b then the line is straight.
Any other phase it is curved thus dictating the surveyor to use the following curve formulae:
D=7500 {units{/(sq.rt 7500)/1[(0.885b)x 421.11643]}}
Where D is the Dodge amount of the offset directive deflection from the tangent external.
Pay close attention to signs in the equation.
Hope this answers your question!
Have a great week! B-)
ya lost me!;-)