As time marches on, things change.
I once pulled a 66' link chain, at a surveying convention. I only pulled it maybe 300', in wet grass. Do you know that the pull handle is a necessary accessory? Those things are HARD to pull, and they leave a rut.
I pulled tape, to make a living, until 1986, when we went EDM. This was K&E Autoranger, on a TM 20c theodolite.
Then, later total Station, which we still have. Topcon GTS 3-C
Then of course, L1 GPS (LOCUS).
Then, RTK, GPS
What I am saying, is that when retracing, it is good to know what kind of tools the person you are retracing, was using.
I have triangulated across valleys, and rivers.
By this means, I know the right place often to throw the errors, when I discover them.
I think I am an old fart now.
Some of the younger generation, has little use with a transit, and tape.
Since the actual survey CHAIN is in disuse at this point... when did the tape sort of take it's place?
Wow. It's been a ride.
N
Q: How do you measure distance?
A: ...repeatedly 😉
Nate, I'm glad you've got insight on the difficulties we, as surveyors, have had over the years when recording distances.
It seems lately like a number of us put too much emphasis on distances. I recently retraced a 1968 survey that had something like 660' from the 1/4 corner to the POB. The 1/4 corner was in place at the bottom of a deep hole in the asphalt. 660' or so up the road was another hole in the asphalt with a nice old piece of rebar at the bottom...it was three tenths short of record.
Knowing what chaining was like back in 1968 I could surely understand the two or three tenths. But someone had put a shiny new mag-nail at the "exact" record distance...just on the edge of the hole in the asphalt.
While I was happy to have found the corners set in 1968; someone else was apparently disgusted with the 45 year old survey's precision. And, of course, they set their new shiny mag-nail and washer just to let us all know how well they could measure. :pinch: ...
Keep up the good work and hug them kids.
> Knowing what chaining was like back in 1968 I could surely understand the two or three tenths.
Not disagreeing with the validity of the monument, but 3 tenths in 660 feet is pretty sloppy chaining, even in hilly ground. It may have been the way those particular guys *did* measure, but it sure isn't the way they *should have* measured.
In my opinion, every student or every license applicant should have to do a few labs on a transit and chain or tape. When we have used these tools, and realize that these were used to lay out the United States of America, you should have some degree of respect for these tools and our elders that used them.
You would have an inkling that those numbers on the 1960 plat are NOT perfect, and could not be perfect, and were not intended to be perfect, so why would we use GPS to make perfect measurements and set multiple monuments?
I have slides that show 3 pins, one set with transit, one with TS 0.4 feet away, and one with GPS 0.1' away from the TS. All starting from the same point, using the same basis of bearings, and reading the same numbers on the 1965 plat. (In one case, there are 13 of these on the same survey). This only confuses, frustrates, and gives legal headaches to the public.
ww CO PLS
:excruciating: - Have a nice day! Or, may your monument prevail over some guy's touchscreen.
> In my opinion, every student or every license applicant should have to do a few labs on a transit and chain or tape. When we have used these tools, and realize that these were used to lay out the United States of America, you should have some degree of respect for these tools and our elders that used them.
>
I was thinking something similar when I posted a reply to a thread above about a chain for sale. I cant justify it, but while reading that thread, I was thinking that practical chain survey surveying should be required in every survey course. I think I picked up few tricks by doing chain and offsett surveys in out in the grass and bush while at college. And it was fun playing with the old time gear; chain, pins, range poles.
> Not disagreeing with the validity of the monument, but 3 tenths in 660 feet is pretty sloppy chaining, even in hilly ground. It may have been the way those particular guys *did* measure, but it sure isn't the way they *should have* measured.
Not sure. I agree that you "could" get more accurate, but I don't think that they were interested in accurate level-chaining, or precise offsets, or many of the things that would make a 1-hour measurement take 6 hours to show some farmer where to put his fence.
One Grader Pass Could Be 0.3'
And it may not be a measuring error, simply rounding the actual measurement.
Most chain measurements I see are reported to the nearest link, 0.3' is within tolerance.
When chaining in a road one cannot really push the pins into the ground.
One never knows, a mag and shiner on the edge of a hole could easily fall in while one is searching for the original evidence.
Paul in PA
> > Knowing what chaining was like back in 1968 I could surely understand the two or three tenths.
>
> Not disagreeing with the validity of the monument, but 3 tenths in 660 feet is pretty sloppy chaining, even in hilly ground. It may have been the way those particular guys *did* measure, but it sure isn't the way they *should have* measured.
I started working in surveying about 1970. Many texts of the era sighted 1:1000 as sufficient for farm surveys. An example is Davis Foote and Kelly, Fifth Edition ©1966 "The usual practice in rough chaining through broken country is to take measurements with the tape horizontal, plumbing from the downhill end, breaking tape where necessary, applying tension by estimation, and no corrections for sag, temperature, or tension." After further discussion the text continues "The corresponding limits of precision are roughly 1/2,300 to 1/1,000." The 0.3 in 660 would be 1/2200 compare that to the following, a table from the same chapter.
I know of older surveyors that used stadia for survey ties under about 800 feet. Rodman used a pocket target in front of the rod to align with three cross hairs. Reported rod reading to instrument man to record. Field check was computation of half and full intervals (total of 1/2 intervals must equal full interval +/- 0.01 on the rod) and vertical angle was recorded. Slope stadia was reduced to horizontal in the office. Remember if the reported distance was sufficient to find the monument called for that was considered sufficient.
California is a different world compared to what you find eastwardly! I've pretty well ran the gamut on retracements in many different states. Stadia, chaining along the ground, calibrated llama foots (long story) etc. All I know is a while back I corrected my edm measurements for downhill because the speed of light travels faster down a mountain.;-)
Pablo B-)
A co-worker told me of overhearing a couple of field crew members arguing as they came into the office, one maintaining that you subtracted the slope correction when chaining uphill and added it when chaining downhill, the other claiming that you added it when chaining uphill and subtracted it when chaining downhill.
My time with a tape for anything beyond a couple hundred feet was limited to the first few years of my career. However, while we only estimated the temperature correction and pull weight, we always used a hand level and always marked the chaining points with nails (dirt) or a red pencil mark (pavement). Line was maintained with a gun (3-man crew) or by eyeballing to a range pole (2-man crew). If it was longer than the tape we chained it out and back, though I think the longest line I ever taped was about 1320'.
I wouldn't expect more than 0.05' in a 660' line, but then I never had an opportunity to go back over one of those distances with an EDM.
I have had many opportunities to check old surveys with edm, and gps.
It is fascinating, but nearly always we come out within 0.20' in 1/4 mile.
0.12 is common.
We worked hard back in the day...
Another surveyor told me, (While working with an RTK unit) "If the satellites fall from the sky, I will hang up my career, as a surveyor".
This same guy once told me that he would "NEVER have picked surveying as a career, if he it was not for EDM's". This was before RTK.
N
How?? I push that damn button just like everybody else here. get over the old days, they Ain't coming back. and you can keep your plumb bob too.
Same way that I always have (since 1968)...
From one point on the surface of the Earth, to another point on the surface of the Earth (usually slope distance these days).
Corrections to the distances are a LOT easier to do than they used to be...
😉
Loyal
