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GLO Double Monuments
Posted by allen-wrench on June 15, 2021 at 1:18 pmI’m retracing a 1920’s GLO dependent resurvey. At a particular section corner, they found a 2″ galvanized iron pipe (the original from the 1870’s would have been a wood post) and set one of their standard iron post monuments “north and alongside of iron pipe”. The proceeded to tie out original bearing trees and set new ones.
My question is, which monument is the section corner now? Are their BT’s to the found iron pipe or to their set pipe? Which one do you set your GPS on and compute from? Yes, I know the difference is small, but I need to set new BT’s and I want to spend my effort on the “correct” pipe.
aliquot replied 2 years, 9 months ago 10 Members · 29 Replies- 29 Replies
The notes appear to answer the question. Many GLO crews had the habit of leaving the accepted monument in place and adding the post and cap to uniquely identify the corner. The accessories would be measured from the actual corner. If they are in place you may be able to validate the assumption the original pipe is the corner.
Be wary of advice starting with, ‘The GLO always…’, ‘That surveyor always’ or other such language. Statements using the word ‘always’ are always false.????
I’ve run into this before. A difference of 0.70′ on a number of corners in the township.
Step back a few feet and think. (I had this whole problem in practice).
1st, look at how well/poorly the retracement survey closes. Typicly around here, if it’s within 3′, it’s gorgeous. Often, putting the courses into a computer, around a section, results in a 5′ closure error. I’ve found them up as much as 15′ or 20′ before.
So, you are retracing someone who finds these values “immaterial”. Often, a 1/4 cor set at mid point, is “off the mid point by 3′” this was “pretty good”. The set monument at the 1/4 cor mid, that “wrong by 3 feet” is “good”.
Now, go back, and compare all 8 courses, record vs what your fancy schmancy GPS turned in.
Now, go back and look at your question. The blm found a pipe. Accepted it. Then set another 1/2 foot away. The one they “accepted” is the one they found. The one they set, is just a, accessory to what they found.
Hold what they held. Yield to what they yielded to. Call their set Mon what it is. An accessory.
Yup. That’s my opinion. Others may differ. But, they are disagreeing with the FINDING of the surveyor you are retracing.
And, now you know my opinion.
Nate
The monument is the pipe. They weren’t thinking that there was a difference back then. I would imagine that they would get a chuckle out of us today.
This was often what they did with dependent or independent resurveys, their monument becomes a memorial so there really isn’t two monuments.
Nate,
Correct for convergence and the use of true mean bearings and the closures may improve…
Thanks for all the great responses. Typically in this area, the GLO would remove the found, locally accepted pipe and replace it with their monument, leaving only one monument. I agree the difference in measurements is trivial – especially in their time – but I was just curious what you all thought.
@thebionicman Usually for this surveyor, the notes would say something to the effect of “the local monument is accepted as best evidence of the original, etc. etc.”, but this time they didn’t say anything like that. But for their time, I’m sure they considered side by side monuments to be like what we consider adding a dimple on an aluminum cap.
I love this site!!!!!!
If I found (today) that the blm Mon was solid, but the pipe was pulled out and loose…..
I might hold the blm Mon. With this explanation. That I believed that the pipe was accepted, pulled, and the blm Mon put into its place.
The idea is to leave tracks based on reason and logic.
Thank you,
Nate
Unfortunately there are people in our profession that would yank everything out and set their own ??monument?. Makes re-tracing more fun. (especially if you find the original corner 10?? away from their ??replaced original corner?) ????
That 1/2 foot, or 0.70′, from 1922, is like our 0.04′ of today.
I’d guess they’d say “it’s all the section corner”.
N
Food for thought…
The trivial of today may be the loss of a buildable lot tomorrow.
As I’ve ranted on numerous occasions, correct is an identity, not a distance. There is one correct location for the corner. It is our duty to recover and memorialize it. Anything less is the unauthorized transfer of real property from one owner to another.
Place the corner where the facts would place it in similar situations. Anything less makes our work inconsistent (and probably impossible to defend).
Usually the GLO surveyor would run a number of crews. And they would not lay out the township as described in the notes. They also would cross township lines dropping off monuments and stubbing out 1/4’s as they went. What sometimes happened is that the crews crossed each other, resulting in double original monuments. I have an interesting 1924 investigation that the GLO did for an 1881 original survey and they discovered double original stones along a west Range line. They were 600 feet or so apart east-west. We also found another set of presumably original monuments 900 or so feet apart along a different Range line, these were in a north-south direction so it does happen.
- Posted by: @mightymoe
Usually the GLO surveyor would run a number of crews. And they would not lay out the township as described in the notes. They also would cross township lines dropping off monuments and stubbing out 1/4’s as they went. What sometimes happened is that the crews crossed each other, resulting in double original monuments. I have an interesting 1924 investigation that the GLO did for an 1881 original survey and they discovered double original stones along a west Range line. They were 600 feet or so apart east-west. We also found another set of presumably original monuments 900 or so feet apart along a different Range line, these were in a north-south direction so it does happen.
Stubbing out certainly happened, but I think “usually” is too strong a word. I have experience resurveying GLO/BLM surveys in 7 states and have only seen this a couple of times (less than completely fraudulent surveys). Maybe they usually did that in your area?
@allen-wrench What did the notes say?
Perhaps that is what you should do, and record it. (Leave one single monument, whatever you decide…it increases the likelihood the next person will choose the same as you.)
-All thoughts my own, except my typos and when I am wrong.@aliquot Basically, it said they found a pipe, and set a GLO monument alongside. I guess it’s implied that they accepted the pipe as the section corner.
my usually refers to more than one crew. I believe crossing township/range lines is more unusual.
And yes, stubbing out 1/4’s would be a normal practice here, survey with caution always.
It always depended on the name in the field notes, pick up a set, look at the surveyor and grin or groan.
I haven’t resurveyed GLO in 7 states only 6 for me.
@nate-the-surveyor “Putting the courses into the computer” will only work if your program is set up to handle geodetic bearings and you are using that feature. Otherwise you will have to make corrections.
I did not know this for years. However, after knowing, and learning, we learned to apply it manually. In this area, theta is close to 55″ per mile. (EW) This can be approximated in, and it’s better than not doing it.
Nate
@nate-the-surveyor in the northern latitudes convergence is a thing to contend with. This is especially true when retracing 3 or 4 sections.
I actually quit using projected coordinates to compute GLO sesrch points. Use the plat distances to proportion lats and longs from knowns and things really tighten up.
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