East-West section lines are not on a straight line.
Manual 2009 2-13:
By statue in the PLSS datum, the term "straight line" is used when describing a line of constant bearing.
"Most lines in the PLSS are intended to be surveyed as lines of constant bearing."
2-14:
"Other examples of lines described as as lines of constant bearing include section lines, subdivision of section lines, and many grant and reservation lines."
The manual is pretty clear on how the lines were supposed to be run on the ground, but as always, those lines may not have been run in accordance to the manual. Which is why the next section 2-15 discussed Line of Sight.
Chapter 3-99+ Subdivision of Sections, is directions to the Drafter interpreting the field notes.
East-West section lines are not on a straight line.
And at every solar transit setup, the instrument was pointing astronomic north and if a east-west line was being run, the instrument man turned a 90 degree and kept running the line.
I think most can figure out that the line will end up on a curve.
Keith
East-West section lines are not on a straight line.
Thanks. Would it be cheating to correct it?
jud
East-West section lines are not on a straight line.
Thanks Jered,
Jud should read the sections on "Line of Constant Bearing" in Chapter 2 of the 2009 Manual!
Does not seem to leave any doubt about curved lines!
Keith
East-West section lines are not on a straight line.
How about reading 1-21 in that manual, that is where the intent of the rectangular system is defined. The system is set up so all interior section corners are set on a line parallel to the East Township line which was intended to be ran on the true meridian. The internal E-W lines are ran as random lines first, corrected and ran back on a true line, no constant bearings taken into account. The system was intentionally set up so that once the Townships were established, the layout of the individual sections was to use a rectangular method "Plane Surveying" to create the 36 sections within a township. The controlling line for all internal corners is the East line of the Township which defined the N-S directions of the lines ran North from the pre established section corners on the South line of the Township. Hard sell it is and much disdain for any who believe that the common held belief of today about what was done in the 1860's through the 1890's are in error.
Won't convince any with any more posting, only a thoughtful study of the intent of the PLSS in the late 1800's can change ones views. Re-tracement of that work can only be done by knowing what they did, what the BLM is doing today in Alaska has no bearing on 1870's work.
jud
East-West section lines are not on a straight line.
OK, lets say for example the east twp line was run as North, if all the interior north-south sections lines were run "parallel" to the east twp line, are they true parallel lines as defined in plane surveying or geodetic surveying? In other words, in plane surveying two parallel lines will never meet no matter how far they extend. In geodetic surveying (which is what a solar compass accomplishes), two parallel lines will meet at the north pole, therefore, they are not, by definition, parallel in plane surveying methods.
East-West section lines are not on a straight line.
The internal E-W lines are ran as random lines first, corrected and ran back on a true line, no constant bearings taken into account.
Is this a quote or your words?
Makes a difference, ya know.
Keith
East-West section lines are not on a straight line.
The 73 manual states in 1-21; In order to make the sections represent "square miles" as nearly as may be, the meridional lines are run from South to North and parallel to the East boundary of the Township for a distance of five miles from the South boundary.
These are run and monumented as true lines. The remainder of the section lines are all run by random and true between the established section corners. This produces rectangular sections, 25 of which contain 640 acres each, within allowable limit. It goes on.
jud
East-West section lines are not on a straight line.
Brian,
The north-south section lines are to be run parallel with the east boundary and you can see this on the sample plat. Depending on the latitude of the township of course, but the lines are run at one minute intervals to get the parallelism.
These are true astronomic parallel lines.
Keith
East-West section lines are not on a straight line.
I have read and reread you reference 1-21 and fail to understand anything different than what I have posted.
If you have a point, I missed it!
Keith
East-West section lines are not on a straight line.
Jud,
I have no doubt that the methods that I used in the field with transit and tape (chain), that these procedures were handed down over many years and my procedures on bending the line, (changing the bearing on my transit straight lines) were basically the same as the GLO surveyors used many years ago.
Hence, the east-west lines have always been curved in the PLSS.
Keith
East-West section lines are not on a straight line.
Inasmuch as the RANDOM LINE is run “on the curve” (or should be in theory), any ADJUSTMENT thereto would have said “curve” incorporated therein by it's very nature.
Now considering that the latitudinal correction for a ¼ Corner is only about 0.15-0.2 feet (0.2-0.3 links) in my area, and most original surveys are returned to the nearest LINK, this “correction” falls below the signal to noise threshold of the original survey.
Be that as it may, I still believe that the “correction” should be made according to the “rule.”
Would I reject a MODERN ¼ Corner that was re-established without the “correction?” Of course NOT!
Loyal
East-West section lines are not on a straight line.
Sage advice from an experienced PLSS land surveyor......Thanks Loyal.
At the time that I was running line, I never considered the finger length distance that I might be off if I ran a straight line without correcting the bearing, or just ran a solar line.
Matter of fact, I didn't much care about any finger length distance!
I would have to imagine though that the youngsters of today would really shake their head when they find my 1/16th corners off line by a link or so?
Keith
East-West section lines are not on a straight line.
Back in the day-pre 2000's-the BLM would set a prorated corner on the east-west line and the monument might be north or south of the line a bit. I sure they were trying to get the line curved, but it was usually a bit "off".
Now, however, that the crews are using GPS the corners will fall the 2" south of line and right at the midpoint. At least that's what I'm seeing.
GPS makes it slick to calculate the curve-just use the lats and longs and prorate them.
East-West section lines are not on a straight line.
Hey, how about that!
Even GPS gets it right.
Keith
East-West section lines are not on a straight line.
Agree with you, Judson.
(Don't pass out 🙂 )
This discussion does get tedious, though, doesn't it.
Sometimes I feel like Ian's horse.
Especially since the outcome is meaningless.
Don
East-West section lines are not on a straight line.
Don,
I agree that it is tedious!
What does it take to make some surveyors realize we live on a globe and east-west lines are curved?
Tell us how oh great one and maybe the argument will end.
Ya can't believe in a concept that is not there, and try to justify it in the Manual, when it ain't there.
Keith
East-West section lines are not on a straight line.
The answer is in black and white in the Manual, all you have to do is read it and understand it!
2009 Manual, Section 3-114 Appeared Out Of Midair.
However it has nothing to do with retracing almost all the public land in the USA, since that is not how it was laid out.
Paul in PA
2009 Manual, Section 3-114
Again: have you ever retraced a section line in the PLSS?
