Are the corners consistent between the GLO surveys? All originals? Not proportioned?
Are the corners you are using for your analysis solid remonumentations of original corners or are they proportioned?
Right now, the data is being constrained by natural calls within the 120 miles.
Every stream and waterway over 4 links width was denoted by the 1808 surveyors(government). I'm applying constraint with north-south streams that appear to be unaltered.
While this is not as "accurate", as using the presently located monuments . . . that is section and township corners, the locations are then compared to the accepted section/township corners.
In 120 miles . . . or for that matter, in 5 miles, the natural calls not only bring me to a specific point denoted in field notes, but are generally plenty accurate enough to get a feel for the idiosyncracies(sp), of the measurements.
While many of the accepted monuments(sections/townships), have been located, I have no interest in constraining the data further at this time . . . although, as I said, I do compare them and the comparison seems to fit rather nicely in most places.
My hope is to eventually attempt to recover a few of the original placed monuments.
After all is said and done, I'm hoping to understand the dynamics of measuring with a chain(or 1/2 chain) in the early years of Ohio.
I do not accept the premise that all the "highly qualified", "original", surveyors of the day, made no attempt to measure as accurately as possible and I'm even less inclined to wholeheartedly accept that they all added extra links to their chains for good measure.
It makes no sense to me for a surveyor who is reportedly of high esteem in his field, who takes an oath to do his best and especially for the later government surveyors who "re-surveyed", the line(with the purpose of reporting on the accuracy of the previous survey), would bastardize their reports with "extra" links in a government supplied chain that was manufactured to accurately(for the day), measure 100(or 50) links of length. Let's bring out the 13 inch rulers and the 17 oz pounds while we're at it.
This "add-a-chain", thing sounds to me like something a "private" running-sared surveyor(who could've been any Tom, Dick or Harriet with a compass and piece of rope(?)), would do later on, in order to distance himself/herself from ire and scorn for "shortening" a land-owner who feels cheated. I feel there must be a more innocent reason for the difference . . . I want to know what this was.
In any case, it will be what it will be, but I find it important to know one way or another, why a half-section, or quarter-section from one end of a section, doesn't agree with one from the other.
I need to know, cause I want to know if this is why multiple section and half-section corners exist.
How can we surveyors(in 2012), "follow in the footsteps", of the original surveyors if we don't even know the actual mechanics of how they actually measured and the most likely reason for these longer measures?
This almost constistant "lengthening" by a number of "original" highly qualified(credentialed), surveyors of high-esteem, in my mind needs to be understood if we expect to understand in 2012 how a line got somewhere . . . especially when it doesn't quite fit our 2012 total station measurements.
In this neck of the woods many topo calls are notoriously inaccurate ( obviously exceptions do exist, and they certainly should not be ignored). That being said I would not get too worked up about perceived differences in chaining until you start getting more reliable measurements of your own to some corners with solid pedigrees on the ground, then I would take a closer look at the data to see if your hypothesis is being supported. Good luck, this sounds like a fun project. Good corner hunting to ya!
I don't know if it would help but I do believe that Al White has some writings regarding chaining methods employed by the GLO, specifically the 33 and 66 foot chains. Perhaps these could give you some insight, sorry I don't have a specific reference, just working off memory here.
I'm kind of curious if anybody ever uses an index factor when restoring lost corners under these conditions. My country is rolling praire interupted by steep canyons so any kind of consistent index factor is out of the question. When retracing and reestablishing corners of an original survey, aren't we trying to follow their footsteps, in searching AND setting corners? Just wondering what the PROS think?! Have you ever? Would you ever?
