We've got a bunch of woodland that's partly on our property and partly on a neighboring (vacant) plot. Runs for about 300' or so, and there's a boundary marker either side of the woods.
I'd quite like to add a few more markers within the trees, just so we know where the boundary is (and maybe fence at a later date) - question is, how to mark it out? The woodland's too dense to see through to the other side, even at night with a flashlight on one of the markers, so I can't just walk and "home in" on it.
I'm not sure that GPS is accurate enough to do it that way - any other clever tricks?
Did wonder about running two lines, meeting at one of the markers. All I need to do is get them straight through the trees (which might be a challenge in itself) - then I can presumably measure distance from each to the other marker at the far end, translate that to a scrap of paper, and calculate where the "true line" is between the two markers for any given distance along one of my guide lines. Does that make sense? Maybe there's a simpler way, though...
Ideas on a postcard, or on usenet, whichever is easier.
You did not say why. If you are just looking for a general idea of how big the lot is, then running down the trees is okay. If you want to actually do something like build a fence, etc., then you probably should get it surveyed.
Ahh, there's a possibility that the vacant lot is going to be sold, so I figured I should maybe mark the line a bit better than just the two boundary poles. The lot's shaped such that any buyer would be unlikely to pull trees down to put a building in (it's about 4 acres I think and the extra effort of taking down an acre of trees doesn't seem sensible) - but some folk can be strange :-)
We might just buy it ourselves eventually, but have too many financial commitments for the next 3 months to think about that (OTOH once the snow hits I bet it won't get much interest until next Spring)
Yes, calling in a professional is one option, although I'm curious how they do it when they don't have line-of-sight either. I doubt 6" either way is any big deal (it's just not the sort of place where people get pissed about that kind of thing!) but I'm not sure if GPS is quite that accurate (at least not the civilian stuff)
Run a line parallel to the existing markers but outside the wooded area. Then from any point you like on the reference line, measure perpendicular into the woods the same length as the offset of the outside line from the end markers.
But all they would do would be to confirm the location of the existing boundary corners--no need to survey where the straight line between two marks actually runs for the legal description so they won't do so.
As for finding the line itself lacking line-of-sight, manually it's painstakingly working one's way thru from one sighting to another.
I don't know what the inexpensive handheld GPS gizmos can do; I've never had one or looked to see as never really cared that much. BUT, US WAAS static accuracy is +/- (roughly) 30". This is what's freely available but not guaranteed availability.
Additional corrections can be made to a single signal but afaik these are all subscription services and whether the cheapie devices include that cost in the upfront purchase cost I don't have a clue.
We use John Deere AutoTrac(tm) with their proprietary SF2 subscription service on the tractors/spray rigs/etc. which has an absolute static accuracy of +/- ~10" but repeatability of tracking of better than half that (the latter is the more critical for our purposes of controlling row spacings and spray coverage as opposed to your desire to know where a point is physically located).
So, all in all, I don't know what you could get inexpensively but I'd expect more like the 30" rather than the 10" numbers.
FSA (USDA Farm Service Agency) uses GPS to do monitoring/compliance on acreages but they, of course, have access to whatever level of technology the DOA(griculture) has access to. They routinely print out computer-generated maps down to the 0.0001 mile (1/2") but I seriously doubt the data are that accurate only that that's what their silly compter output formats are. I'd guess they're roughly at the 10" value overall although I don't think any of the technicians nor even our office director have that level of knowledge of the technical details--only how to use the supplied equipment and software systems.
I routinely measure fields by the rolling wheel technique for waypoints in the total field for operations such as haying or similar and ignore anything less than roughly 1/10A (which is a strip roughly 1/2-ft wide over a half-mile row) and have never been called to task. That close is reasonably easy to get as each revolution on a rod wheel is 1/4 of
16.5-ft or 4+ ft so 1-ft is a quarter revolution. 1-rod by 1/2-mile is
1A and most of our land is farmed in quarters which are 160A or 1/2-mi square so that's far more convenient measure rather than feet-inches by hand. The JD AutoTrac readouts can be switched to whatever units one wants since it's all computer-based, of course.
But, all that to say the higher accuracy GPS numbers above don't come cheaply (at least w/ green paint (or red, either, for that matter).
Aha - yes, that's a good plan. There are really too many buildings on our side of the line to do that, but I can do it from the vacant plot (the folk who own it currently are good enough that I know they won't mind)
I did a fairly good job finding my lines using an "engineers compass" and a plot plan. The "engineers compass" is like a tiny cheap hand held version of a transit, but worse, it came from WalMart. Very very basic. Wait for all the leaves to fall. I went to the one and only corner marker I could find and using the compass turned the plat map so North is North. Aimed the compass site using the compass markings and lining it up with the line on my map. Sighted through a tiny lens and a single cross hair as far as the next tree it hit. Walked to that tree and did it again. Kept doing that until I found the other corner markers, and in 600 or so feet I was off by 6 feet. Sure that's a lot for some things but I just wanted an idea of were the corner of my property was, and there it was, well marked.
Turns out the other land owner had some pro's come through a couple months later. He showed me one place I had marked, about half way between corners, I was off by only 6 inches there and he acted like that was a lot. Only reason I ended up 6 feet off in the end was due to the terrain. A lot of it was literally stretching and climbing up the mountain a couple feet at a time and getting myself on the uphill side of the next tree to rest against. I accidentally rode down the mountain on my ass with a shit load of leaves under me and in front of my feet. It was kind of fun.
As far as markers, they use an ax and take off the topmost part of the bark, it didn't get down to fresh wood. Then those spots were painted blue. Some with 4 blue lines like a square, some just 1 or 2 marks. I'm guessing the marks meant something that had to do with were the exact property line was... in front or in back of the tree.
There was one spot where I am close to the property line and they marked it with the 4 blue marks and a small yellow no trespassing sign in the middle. It seemed to stick out like a sore thumb and from the driveway it drew your attention. So I mixed up some mud, real mud, dirt and water, and plastered over the blue marks. And I got a few large leaves to stick on the nail holding the little sign. Now I don't see it, but it's still easy to find if you are close and looking for it.
The only thing comes to mind to me. Use a high power laser, and burn through the trees and leaves. There should be enough visible burn damage to follow with the string.
No, I don't have a high power laser listed on Ebay for such a purpose.
I doubt this is workable, but it's fun to imagine.
Clear a path using a machete to remove brush and small limbs even small trees. Hopefully you will be able to see through. If not offsetting a small amount to the side will sometimes allow you to see. Put something on the far end that is large and highly visible.
Your county tax assessor has a high def overhead (satellite) photograph of your property, with the survey points marked. As government property it is available to the public. If the photo was taken when the ground was visible beneath the trees you may be able pick out enough points along the property line to get a rather precise set of ground points.
It's possible that you can locate the corners yourself by zooming in on Google maps -- I just checked it out and can on my house -- even though there are a lot of trees blocking the view I can still pick out enough landmarks to be able to draw a property line.
Since the lot next door isn't wooded, that's your solution.
I once worked for a survey company for a few days (a long time ago) and my job was to cut "sight lines" through a wooded lot that was going to be surveyed. It was no fun -- mostly just hacking away brush and small trees to be able to see from one end of the lot to the other. It involved multiple sight lines because the survey had to also show the elevation of the land on the interior section. I guess there were no other magic tricks the surveyor could do so he had to pay us to chop sight lines all day long for a few days. We were doing it in the middle of a hot summer.
If you do end up having to chop any sight lines, it will be a lot easier if you can wait until winter after all of the leaves have fallen off the trees.
I seriously doubt the OP was talking about the very expensive and accurate type of GPS used for surveying. I'm not sure one would work for his particular application anyway, as those units need open sky above to achieve that accuracy. This is a thick grove of trees...
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