This may or may not be interesting.
I ran 3850' of compass line through moderate to steep terrain in the 3rd, 4th or 5th growth redwood forest in Mendocino County. Lots of huckleberry. No poison oak.
This is using a 4" K+E staff compass graduated to the nearest degree with the current declination set in it (see my avatar).
Our procedure was, clear the line, rodman holds a pink lath up, I put it on line and he drops it down vertically. I used a Leica Disto to get a rough distance lath to lath (eyeball hold over the lath and shoot his back). The first 1600' has a couple of ravines but not too bad. The last bit drops steeply down to a road. The line follows the road for 300' then dives off into the steeper part to the finish. It runs from a concrete monument to another set in the early 1960s. The bearing of approximately S 79-50 E used is from a solar observation done in the early 1960s.
My falling to the monument on the east end was 1' south to the monument which is better than I expected.
This week I traversed the line and tied my laths set with compass. The results are I drifted to about 3' north of line by about 500' then paralled the line for the next 1000' then started drifting back towards the line towards the end.
We are mostly on a north aspect so there may be a bias in our lath setting left (running east) which may account for drifting off line like that. The last 500 or 600' was through an almost clearcut harvest and better visibility probably allowed me to get better line.
Did you carry a firearm the first 500'. Local attraction in the first 500'?
B-)
Pablo
> This week I traversed the line and tied my laths set with compass. The results are I drifted to about 3' north of line by about 500' then paralled the line for the next 1000' then started drifting back towards the line towards the end.
Would any of that be explained by the sight vanes being out of plumb when the compass level vial indicates level? I'd think the easy test is just to set the compass up and orient the compass so it is pointing at a plumb line at about the same level as the instrument, then check to see whether 30deg up and 30deg down from level are also pointing at the same line.
That is a good point.
A little more explanation if you would please, Dave.
Why did you run the compass line?
Why did you re-run it later with, presumably, better precision?
Which of your wonderful stash of whiskies are you drinking as we speak:-)
Don
I drank some Bulleit Rye last night. I opened a bottle of port tonight.
I ran the line for the purpose of marking it approximately and to do initial recon. Usually there is a surprising amount of old flagging on the lines but in this case there was none on-line. I ran through three recent harvest areas but we should be running along the edge. The line got severely mis-marked (not by a surveyor). One stump was a 13' diameter redwood maybe 100' from the monument on the east end. I was directed to map the stumps which requires traverse control and it is an opportunity to check the accuracy of my compass line. Almost all of the stumps are more than a few feet from line.
We see occasional stumps 1 or 2 feet from line which is understandable and meets the functional precision of timberlands with 3 to 4 foot trees but 40 and 50 feet is a little ridiculous. Also when we see old rotted stumps we can't really tell who did it and it has been too many years to pursue it anyway.
Henry Sipe .....
would have been proud of you!
There is still room for a good compass in every survey vehicle. Henry would have said a good compass & procedures were all you needed. Not me, but it is a great tool for recon.
For those that haven't read it, you ought to get hold of his book called "Compass Land Surveying". You'll learn from it!
Henry Sipe .....
:good: :good: :good:
If the original line was run with a compass and (maybe) you have truly followed in the footsteps; the nasty question that you have now uncovered is: Do the monuments at each end hold and you run a straight line? Or should the line be the meander line subject to magnetic field issues you can and have reproduce? The value of timber near the line might justify the cost of the fight.
Henry Sipe .....
There was a Sipe-Sumner compass on ebay a few weeks ago. It went for just over $500.
It is still possible to get a brand new one from Warren Knight-$2300.
Henry Sipe .....
> There was a Sipe-Sumner compass on ebay a few weeks ago. It went for just over $500.
>
> It is still possible to get a brand new one from Warren Knight-$2300.
A Sipe-Sumner compass in working condition for about $500 sounds like a real deal to me. For $2300, I think I'd probably rather have a Wild/Leica T-0 with a Disto mounted on it. Granted, a staff compass is much faster to set up, but the T-0 is pretty cool.
