A little difference - now understood
> Interesting to observe how different people approach the same problem using differing solution methods.
I used to use transformations to study bearing trees, but have found that the least squares approach is a bit more powerful, particularly in cases where either the bearings or the distances are significantly better than the other, and where the certainty of the positions of the bearing tree evidence varies from still standing to spike at center of stump hole.
It allows the directions of the bearings to be based upon the "North" direction that itself can be solved from the adjustment by expressing them as directions from the corner sought that also include a direction from that corner to some other corner connected by the survey.
Somewhere I have an example of the solution of a corner that was originally established in the 1850's, a problem that involved the records of two different 19th-century surveys with ties to sets of bearing trees that weren't identical and both surveys with different "North" directions.
What was the question and what a pot of answers? There's Steve D's SWAG and "Miller time," '66's proof in the pudding, KrisM's swinging of arcs. From there, discussion strays to obliterated and lost corners, etc. As far as answering the question, it appears only ML took a stab at it with Norman Ok suggesting a similar solution. I can pretty much follow ML. Kent's calculations seem to leave out some details. Be nice to know some more about how 234 became a "random point" and then changed to "stake and mound" coordinates?
I don't think dogs could sniff out the corner but, if conditions would allow, it would satisfy some curiousity to be able to take an infrared scope to look at the ground to see if any patterns might show up. Probably, there might be better infrared contrast sometime after sunset and when it has been dark for a while.
Kent, what are "FeetUS"? Haven't ever seen that designation.
> I can pretty much follow ML. Kent's calculations seem to leave out some details. Be nice to know some more about how 234 became a "random point" and then changed to "stake and mound" coordinates?
I suppose that I should have assigned a different Pt. i.d. to the final corner coordinates. Pt. No. 234 the "trial point" was just a preliminary idea of where the corner was before really getting into the problem. Subsequent Pt. No. 234 was the final solution.
The calculation really was as simple as I described, just a least squares solution using the compass bearings reported by the 1949 surveyor (after correcting N33W to N27W) as a set of directions with standard errors of 10' and the distances as reported with standard errors of 1.0 ft. Rounding to 30' has a roundoff error of about 15' and 0.68 x 15' = 10' as an adequate approximation. The residuals from that adjustment looked so realistic, that I didn't bother to rerun it with standard errors of 0.5 ft. on the distances.
> I don't think dogs could sniff out the corner but, if conditions would allow, it would satisfy some curiousity to be able to take an infrared scope to look at the ground to see if any patterns might show up.
I tend to doubt that anything would show up. The soil is very shallow in that location (about 6 inches on average, probably) and in the location of Pt. No. 234 all that remains is a scatter of rocks that are probably what is left of the rock mound formerly in place. Basically, the original stake and mound was just built on a limestone outcrop with a thin skim of soil. I made a fairly careful examination to see if the base course of the mound or any stub of the stake remained and found nothing conclusive. Most likely, it was all removed by later fence builders.
> Kent, what are "FeetUS"? Haven't ever seen that designation.
That is Star*Net's shorthand for US Survey Feet as distinct from FeetInt.
What do you think scatters the stones? Most original GLO corners I find with witness mounds are not scattered.
> What do you think scatters the stones? Most original GLO corners I find with witness mounds are not scattered.
I'd say almost certainly some fence builders scattered that rock mound after 1949. Unless the fence builders are careful to set the fence off the mound, when wire fabric is being used, the mound will most likely not survive intact.
