Okay, the tract is over 8,000 acres extending roughly five miles East and West and the bearing basis note in the metes and bounds description informs posterity that:
Bearing basis = True North based on GPS observations.
Over the project extents East and West, the convergence varies between about -1?ø20'36" and -1?ø18'16". The northern limit of the project is about 23,000 ft. distant from the Southern limit, so "true North" means merely "Northish" without knowing where exactly the scrivener had in mind that "true North" would mean geodetic North.
That is, if "North" refers to the meridian of longitude at one edge of the project then a line run parallel to that direction on the other side of the project on the theory that it also would be "North" is in error by more than 0?ø02'20", which amounts to an absolute error of sin (0?ø02'20") x 23,000 ft. = 15.6 ft. along that far side. That is good enough to navigate to with a recreational handheld receiver, but not a whole lot better.
The survey was made in 2005, so the first thing that came to mind was that the surveyor really meant that the bearings of all courses were the mean geodetic bearings of the same. Fortunately, that nightmare never arrived since the geometric closure of the figure indicated that it really refered to some mystery projection with a Y-axis parallel to geodetic North at some unspecified point within RTK radio range of most of the points on the boundary,
I guess that it would have just been too easy to use the appropriate zone of the Texas Coordinate System of 1983, as delivered by OPUS, instead of leaving posterity to guess, eh?
Kent McMillan, post: 439256, member: 3 wrote: Over the project extents East and West, the convergence varies between about -1?ø20'36" and -1?ø18'16".
And, to be clear, by "convergence", I'm referring to the difference between geodetic North and grid North in the South Central Zone of the Texas Coordinate System of 1983 at a specific meridian of longitude, not the relative convergence of the meridians from edge to edge of the project.
Well that has to beat the crap out of the jackleg, dipsh*t, dufus & goofus, "magnetic" bearings, which (based on your earlier posts) are +/- several DEGREES from the real world, and Typical for Texas.
Be that as it may, it is an idiotic "basis of bearing," without additional metadata. Unfortunately, I see that king of ignorant crap all of the time.
It didn't start with GPS/GNSS, anymore than ASSUMED bearings based on who knows what, started with the pencil .
Loyal
Yes that's fairly common here.
No metadata or legacy info.
I think the mindset equates it to an astronomic observation somewhichwayhoworanother.
No convergence no nothing
No tickee no washer to be un PC.
Loyal, post: 439258, member: 228 wrote: Well that has to beat the crap out of the jackleg, dipsh*t, dufus & goofus, "magnetic" bearings, which (based on your earlier posts) are +/- several DEGREEs ...l
Actually, the 19th-century surveyors who reported the variations ("declinations" for the geologically minded) to which they had adjusted their compasses left a very good means to compute the directions of the lines they ran. I have no complaints about that, although I'm sure it would blow the minds of the folks in PLSSia who expect everything to just be "true", with no further inquiry necessary.
Kent McMillan, post: 439260, member: 3 wrote: ...although I'm sure it would blow the minds of the folks in PLSSia who expect everything to just be "true", with no further inquiry necessary.
Can't you even rag on your fellow Texas surveyors without dragging out-of-state surveyors into your bailiwick?
You should write a book with your vast expertise about surveying in the PLSS. I'm assuming you're suggesting the entire United States would obviously be better off if we reported all our values in the Texas Coordinate System of 1983. 😉
paden cash, post: 439261, member: 20 wrote: Can't you even rag on your fellow Texas surveyors without dragging out-of-state surveyors into your bailiwick?
[SARCASM]There you go again with your rhetorical questions, paden![/SARCASM]
Kent McMillan, post: 439260, member: 3 wrote: Actually, the 19th-century surveyors who reported the variations ("declinations" for the geologically minded) to which they had adjusted their compasses left a very good means to compute the directions of the lines they ran. I have no complaints about that, although I'm sure it would blow the minds of the folks in PLSSia who expect everything to just be "true", with no further inquiry necessary.
The GLO notes for the parts of this PLSS state I've looked at report the variations to which they had adjusted their compasses, so most of our minds aren't blown by the idea.
This is not to claim that all current surveyors do a good job on basis of bearing nor other metadata. There certainly is room for improvement.
How much simpler can it be? All one must do is turn on the black box and believe whatever it says wherever you happen to be on that 8000 acres. No such thing as localization, convergence or any of those other bizarre terms that eggheads attempt to use to defend their work against that of anyone else. Just push the damn buttons and print what they tell you!
I'm in the middle of retracing one of those...
S'veyor also ROUNDS his dimensions to the minute. So, it all fails to close by 0.75'. So, if you sort of Adjust/fudge it together, then you kind of get it back like it was.
ALSO, many of the "Corners" are fence corners. No monument found or set...
ALSO, the pins that were set, are merely line markers, with NO reference to how far from the corners they are. A 2 day exercise in obfuscation.
N
"Assumed" is my pet peeve. You know that someone who says the bearing of N27?§23'18"E from point A to point B was an assumed bearing. If that were true why wouldn't they have just assumed N30?§E. Clearly, they are rotating it to another plat, or they are getting bearings off their GPS box or something else....why don't they say where it came from?
paden cash, post: 439261, member: 20 wrote: Can't you even rag on your fellow Texas surveyors without dragging out-of-state surveyors into your bailiwick?
Well, Loyal showed up and seemed to need a reminder that the Texas practice of reporting the variation at which a survey was made was actually quite a good one and works much better than simply assuming that all bearings are in relation to true North. I'm always happy to offer any necessary correction.
Bill93, post: 439273, member: 87 wrote: The GLO notes for the parts of this PLSS state I've looked at report the variations to which they had adjusted their compasses, so most of our minds aren't blown by the idea.
I don't recall reading any note from Iowa describing the computation of the theoretical bearings of lines using the stated variations at which they were run. Is this actually a common practice? Apparently, it isn't in the parts of the Western US where Loyal has surveyed.
Because I ass-umed it. That's why. That's all you need to know to discover the differential bearings between lines. That's what really matters in the first place. All this fuss over basis of bearings is just that............fussin' over nothin'. Pick a few found monuments. Look for agreement. Then rotate whatever your magic box is thinkin' to what the ass-umed bearings tell you and roll on. Everyone understands the snootiness factor (as discussed elsewhere) that creates the insistence that the other guy's basis of bearings is always wrong. Calling the north section line to be north 90 east is just as good as calling it north 89 east or south 89 east or anywhere in between or whatever you choose that is somewhat representative of east as opposed to kinda sorta southeast.
Now, attempting to follow the ancient mariners (early surveyors) who had only the Sun and stars to follow in darkest Africa is a completely different story.
Holy Cow, post: 439296, member: 50 wrote: Because I ass-umed it. That's why. That's all you need to know to discover the differential bearings between lines. That's what really matters in the first place. All this fuss over basis of bearings is just that............fussin' over nothin'. Pick a few found monuments. Look for agreement. Then rotate whatever your magic box is thinkin' to what the ass-umed bearings tell you and roll on. Everyone understands the snootiness factor (as discussed elsewhere) that creates the insistence that the other guy's basis of bearings is always wrong. Calling the north section line to be north 90 east is just as good as calling it north 89 east or south 89 east or anywhere in between or whatever you choose that is somewhat representative of east as opposed to kinda sorta southeast.
Now, attempting to follow the ancient mariners (early surveyors) who had only the Sun and stars to follow in darkest Africa is a completely different story.
Most (or probably all) the time the surveyor is establishing a bearing
I highly doubt you just "assumed" it. See....you are calling the North section line to be N90E or N89E....you aren't assuming it to be S24E. No surveyor just walks up to a point with no orientation and just says "Hey, for the sake of discussion, let's assume this here line to be N18?§12'56.4"W. They got that bearing somehow, and the basis of bearings statement is designed to help someone get on the same bearing base (even if the points on the ground no longer exist)
for the majority of the surveys I do, bearing base has no effect on the final results, as the end points of the lines are controlled locally rather than a projected record bearing. If this note presents a problem for you, Kent, you can thank the great Texas tradition of re-writing legals with every new survey. Simultaneously screwing up ground position and title all in one fell swoop.
Holy Cow, post: 439296, member: 50 wrote: Because I ass-umed it. That's why. That's all you need to know to discover the differential bearings between lines. That's what really matters in the first place. All this fuss over basis of bearings is just that............fussin' over nothin'. Pick a few found monuments. Look for agreement. Then rotate whatever your magic box is thinkin' to what the ass-umed bearings tell you and roll on. Everyone understands the snootiness factor (as discussed elsewhere) that creates the insistence that the other guy's basis of bearings is always wrong. Calling the north section line to be north 90 east is just as good as calling it north 89 east or south 89 east or anywhere in between or whatever you choose that is somewhat representative of east as opposed to kinda sorta southeast.
Now, attempting to follow the ancient mariners (early surveyors) who had only the Sun and stars to follow in darkest Africa is a completely different story.
That would be a violation of standards here. And the standards are fairly loose to begin with as far as basis of bearings are concerned.
Reminds me of a Dennis Mouland seminar years ago when he talked about a surveyor who considered his work correct and unapproachable.
It wasn't snootiness just ignorance and the stubborn conviction that where he placed monuments regardless of inaccuracy was the last word.
Isn't the entire state of Texas on a square grid; no East/West curved lines?
roger_LS, post: 439317, member: 11550 wrote: for the majority of the surveys I do, bearing base has no effect on the final results, as the end points of the lines are controlled locally rather than a projected record bearing. If this note presents a problem for you, Kent, you can thank the great Texas tradition of re-writing legals with every new survey. Simultaneously screwing up ground position and title all in one fell swoop.
BOOM!
