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.
Kent,
I don't know or care why you have such a problem with the PLSS, but bringing it into every conversation in a derogatory light is extremely immature and unprofessional. I appreciate most of the issues you bring forth, but when you bash the PLSS for no apparent reason its usually my last visit to the post. As some say, get over it. No response necessary - I won't be back...
Kent McMillan, post: 439350, member: 3 wrote: That system began in 1837 with the opening of the Texas GLO
Bunch of johnny-come-lately's...in these parts we had almost two centuries of retracement surveying under our belts by them 😉
Jim in AZ, post: 439465, member: 249 wrote: Kent,
I don't know or care why you have such a problem with the PLSS, but bringing it into every conversation in a derogatory light is extremely immature and unprofessional. I appreciate most of the issues you bring forth, but when you bash the PLSS for no apparent reason its usually my last visit to the post. As some say, get over it. No response necessary - I won't be back...
Kent did not start his thread with bashing the easy peasy simple PLSS all you have to do is read the book and follow the step by step instructions on how to solve any survey problem you have, it even breaks it down oh how to do it, by the corners PLSS Surveyors find. He made a statement about a Survey he is retracting and a comment it had on the basis of bearings.
He didnt not say anything about the PLSS until Surveyors in the PLSS system made a statement about Texas.
You guys in the PLSS just need to get over the fact that Surveying in the PLSS is child's play compared to metes and bounds.
Kent McMillan, post: 439295, member: 3 wrote: 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.
Kent, just for your information, I don't recall seeing many old or even new government plats without the mag declination shown. The new plats will have an average statement. The older plats will often show each line with a mag declination. It's not something I pay attention too beyond noting that it's there, there are probably many GLO/BLM plats without it, I only notice it on the newer ones just cause it's so odd to see it there, and on the old ones it's usually on the plat so many times you can't help but see it.
MightyMoe, post: 439481, member: 700 wrote: Kent, just for your information, I don't recall seeing many old or even new government plats without the mag declination shown.
Yes, but isn't the idea that the variation shown on the GLO plats was what was measured via the solar attachment when the line was run and should have been the nominally correct value to run true bearing? Where things get complicated is when lines were run throughout a district by compasses adjusted for the same value of variation without regard to what the actual variation was.
This was done in Texas, for example, as a way of facilitating retracement of earlier surveys made during Mexican period, i.e. a compass adjusted to nominally agreement with the "North" direction to which the earlier surveys referred could follow the lines by running the same bearings as earlier reported, regardless of their exact true directions. In Central Texas, where the actual variation remained nearly constant from the 1830s through about 1870 that was a workable system. Later, though, as the old variation was found to no longer retrace old lines, a number of other values of variation were successively adopted with the object of trying to fit the map "North" in general use throughout the county or district. That is when things get more complex.
It's interesting to look at the old vs. new plats. The variation on the old plat might be about 17-30 and the new one will be say 10 3/4. Which is to be expect of course. Yes most everything is retraced to "true" north. Mag Declination is more an academic exercise.
An example of PLSS "field notes" from 1872, concerning "variation" and local attraction.
Kent McMillan, post: 439494, member: 3 wrote: Yes, but isn't the idea that the variation shown on the GLO plats was what was measured via the solar attachment when the line was run and should have been the nominally correct value to run true bearing? Where things get complicated is when lines were run throughout a district by compasses adjusted for the same value of variation without regard to what the actual variation was.....That is when things get more complex.
If I'm reading correctly, that is exactly what was done during the construction of a township. The north-south lines were ran with an estimated compass adjustment to keep them parallel with the meridian, being the east line of the township.
Loyal, post: 439502, member: 228 wrote: An example of PLSS "field notes" from 1872, concerning "variation" and local attraction.
Scribblings of a barely literate peasant. 😉
An example of Texas field notes from the same era 
Loyal, post: 439502, member: 228 wrote: An example of PLSS "field notes" from 1872, concerning "variation" and local attraction.
Loyal, post: 439502, member: 228 wrote: An example of PLSS "field notes" from 1872, concerning "variation" and local attraction.
And they are likely valid.
Loyal, post: 439393, member: 228 wrote: Well SOP back in the day (except in Texas apparently), was to use astronomical observations (Sun or Polaris).
Loyal
And then there is the solar compass.
Scott Ellis, post: 439472, member: 7154 wrote: Kent did not start his thread with bashing the easy peasy simple PLSS all you have to do is read the book and follow the step by step instructions on how to solve any survey problem you have, it even breaks it down oh how to do it, by the corners PLSS Surveyors find. He made a statement about a Survey he is retracting and a comment it had on the basis of bearings.
He didnt not say anything about the PLSS until Surveyors in the PLSS system made a statement about Texas.
You guys in the PLSS just need to get over the fact that Surveying in the PLSS is child's play compared to metes and bounds.
Oh, good.....I'm glad that the poor, abused Kent has a champion who can come to his defense. I was worried that Kent couldn't defend himself.
Using a solar compass bearings are true.
But how true?
What sort of accuracy would've been typical?
Solar compass readings were typically recorded to 5 minute resolution in the GLO notes. My impression is that is about what is achievable for accuracy with careful work. I hope someone with direct knowledge chimes in.
Operating a solar compass required precalculating settings that needed to be made on a regular basis thruout the day at the same rate that the sun was moving thru the sky.
At each setup had to check the time of day and make the corresponding setting on the solar compass.
I believe that the accuracy of the solar compass was as good or better than any transit at shooting the sun.
Have followed original survey notes from the mid 1800s that the call for North and East was within a minute of sun shots with SMI in 1990 and checked agin with GPS a few years ago.
Tom Adams, post: 439791, member: 7285 wrote: Oh, good.....I'm glad that the poor, abused Kent has a champion who can come to his defense. I was worried that Kent couldn't defend himself.
Actually, Kent has been working on a problem that dates from 1839 that has required reassembling the patchwork quilt of metes and bounds land grants that followed between then and 1939 and it looks as if he was correct in thinking that something major has been overlooked in how the pattern of land grants developed that the official County Map does not disclose.
In Texas, the State owns all of those unsurveyed omitted pieces for the benefit of the Permanent School Fund. So, to find a strip containing about 62 acres in an area of valuable suburbia is just about as severe a title problem as one can have considering how much time, effort, and money is required to actually purchase such a vacancy from the State.
Fortunately, that's not my clients' problem. but it is part of what makes surveying in Texas so interesting, i.e. knowing that the correct answer really matters.
Kent McMillan, post: 439869, member: 3 wrote: Actually, Kent has been working on a problem that dates from 1839 that has required reassembling the patchwork quilt of metes and bounds land grants that followed between then and 1939 and it looks as if he was correct in thinking that something major has been overlooked in how the pattern of land grants developed that the official County Map does not disclose.
In Texas, the State owns all of those unsurveyed omitted pieces for the benefit of the Permanent School Fund. So, to find a strip containing about 62 acres in an area of valuable suburbia is just about as severe a title problem as one can have considering how much time, effort, and money is required to actually purchase such a vacancy from the State.
Fortunately, that's not my clients' problem. but it is part of what makes surveying in Texas so interesting, i.e. knowing that the correct answer really matters.
"... i.e. knowing that the correct answer really matters."
Is this not true everywhere?
Jim in AZ, post: 439895, member: 249 wrote: "... i.e. knowing that the correct answer really matters."
Is this not true everywhere?
Not if all you're dealing with are private lands in a silly putty cadastre that oozes and flows over time under various theories of establishment or implied agreement as senior grants bend and deform to fit the limits of junior grants. In that case the "correct" answer means something more like "whatever".
Kent McMillan, post: 439869, member: 3 wrote: Actually, Kent has been working on a problem that dates from 1839 that has required reassembling the patchwork quilt of metes and bounds land grants that followed between then and 1939 and it looks as if he was correct in thinking that something major has been overlooked in how the pattern of land grants developed that the official County Map does not disclose.
In Texas, the State owns all of those unsurveyed omitted pieces for the benefit of the Permanent School Fund. So, to find a strip containing about 62 acres in an area of valuable suburbia is just about as severe a title problem as one can have considering how much time, effort, and money is required to actually purchase such a vacancy from the State.
Fortunately, that's not my clients' problem. but it is part of what makes surveying in Texas so interesting, i.e. knowing that the correct answer really matters.
