DIY surveyors transit

[RustyShackleford]

Anybody done much DIY surveying ?

My problem is pretty simple. By using hand-held GPS (which is nowhere near accurate enough, by itself, to locate survey irons), and curve fitting my GPS readings to the known bearings and distances of my lot lines, I have managed to predict the GPS coordinates of the ones I could not find, and thereby locate them (the hand-held GPS could get me within a 20ft circle or so).

So I now have found all my property irons (or "monuments"), and I now need to try to flag one of the lot lines. (This is to help the loggers who have the timber easement on the neighboring property to not trespass on my property again - but that's a whole 'nother story). The line is about 900ft long and heavily wooded, a lot of it pretty scrubby stuff that is nasty to clear through. So I can't just eyeball the line between the two irons and flag trees, because I can't come anywhere close to seeing one iron while standing at the other. So I need to transit the line (I guess that's the right verb). I tried it with a hand-held hikers' compass (with flip-up sighting mirror) and missed the other iron by about 20ft. That's about 1-degree accuracy, which I think is pretty good for hand-held, but the 20ft error at the other end is certainly not good enough for flagging the line. And it's not even good enough for clearing the line - I don't want to have to clear a 20ft-wide swath !

So I have built a home-made surveyors transit, roughly as described here:

http://chestofbooks.com/crafts/popu...s-to-Do/How-To-Make-A-Surveyor-s-Transit.html

I haven't tried it yet, so more later ...

 

[jimbom]

Rent a transit. But if it is heavily wooded, a transit may not help unless you cut a lot of brush. I think you will need a better instrument than the homemade for your offsets etc. Right now is the best time in my woods to clear the line. Soon things will leaf out and sight lines will be gone.

 

[WhitePine]

I had the same problem, but a better neighbor. He showed the loggers the corner monuments and told them not to cross the line. I guess the "crap" trees they pushed down hill onto my property didn't count as timber.

Without a real survey crew and pro equipment, I don't know how you are going to do it. I do know Jimbo is right. Now's the best time if you are going to attempt to flag it by yourself.

 

[Prosecond]

I used to buy timber and have located miles of boundary lines using a compass, property survey information, and evidence located on the ground. http://www.benmeadows.com/search/compass/31224855/

 

[RustyShackleford]

Deleted ...

 

[RustyShackleford]

Absolutely right that now is the time to do it. If not the leafing-out, then the ticks etc.

Prosecond, that compass claims to be accurate to 2-degrees. Mine is very similar and I think I can probably get 1-degree. But still, over a 900ft line, 1-degree translates to about 15 feet. That's not good enough for flagging a property line.

The neighboring property owner does not care. I called him and he was pretty unfriendly, pretty much claiming that it was the timber company's fault, not his; I think he's probably correct. The value of the timber is about $1000/acre I'm told, or about $600 for the 60ft x 900ft pie-slice of the trespass. Even with the usual treble-damages, that's about $2K, so no way it'd be feasible to litigate, with the surveying and legal fees. But it's irrelevant, because it's been about 8 years, well pass the statute of limitations on trespass, I'm told. So my approach is simply to mark my line very definitively - maybe even a crude fence.

I definitely am up for cutting a bunch of brush, and once that's done, maybe I can even get a clear shot; I can certainly cover the line with two shots. So I don't think I need a real transit. Plus I just like building things myself. I just want to minimize the width of brush I have to cut.

As best I can tell, the main source of imprecision in my home-made transit will simply be how closely I can get the compass to a given bearing. Not quite sure how to improve on that. Otherwise, the "scope" is just a piece of 2" PVC about 18" long, with a peephole at one end and crosshairs at the other. The whole thing is mounted in a wooden frame, with pivots for elevation. It has a bulls-eye bubble level on top, and I check the the elevation pivot is perfectly vertical using a 4ft carpenters level; I also make sure the compass mounting (onto the frame) is aligned with the PVC. I think the precision in these two things is well under 1-degree ... BUT, it seems tough to read a compass that is only about 2" in diameter to closer than 1-degree. Hopefully no compass deviation, as the whole thing is made of wood and plastic, and the few screws are brass, which apparently is non-ferrous (who knew ?, but I held one near the needle and it is), and mounted on a nice aluminum photographic tripod. Of course the compass has a magnetic declination adjustment, with the right setting from:

http://www.ngdc.noaa.gov/geomagmodels/struts/calcDeclination

I can also sorta calibrate the thing by shooting one of my shorter property lines (where I can see one corner from the other).

 

[jebatty]

Just do the best you can to mark the line, and leave a 50' buffer between the cut and property line you measure. If your line measurement is off 20', you still are on your own property. I own forest land, and I would be really *issed if a neighbor did a cut that trespassed into my land, unless we first agreed on the cut line. Almost the same, well not quite, as the neighbor jumping in bed with my wife and claiming he didn't know because it was dark.

I also have a hand-held sighting compass good to 1/2 degree, a GPS (Delorme) usually accurate to 8' +/-, and working the two together can get a line very close to actual. And based on surveys I've paid for in the past, my line has been better. I've had 3 surveys on one piece of property, and the surveys have disagreed by nearly 50' on the corners over a 900' line.

And in considering corners, they are only as good as the survey which placed them, which around here means they aren't worth much unless the adjoining property owner agrees on the corners. Historical surveys can be notoriously inaccurate, and the phrase "war of the surveyors" takes on added meaning when a person ends up in court.

 

[peakbagger]

I used to have incredible luck with a Suunto Sighting compass (KB14?) for clearing lines. The other bizzare solution that I encountered from a survey crew log from many years ago was "ballon" surveying. A major right of way I was reestablishing with a transit had originally been laid out by a crew which would attach a helium ballon to a known point in the woods on a calm day. Then the surveyor would sight the balloon frokm anotehr known point and drop the transit head. From there, he would clear a line until he could see the point. It was a pipeline right of way so there were long runs of several thousand feet whihc were ladi out with this method. I expect you could modify this somewhat by offsetting form the neighbors line a few feet at both ends and then clearing line on your property so he cant complain.

When they came up with laser surveying stations it made it a lot easier, just run a crooked line through the woods, plot it out on the computer and then come back and set points on the line from the intemediate traverse points. YOu may get lucky and be able to rent a surveying station but most ental places only rent to licensed land surveyors. If you are anywhere near Duplin County, Blanchard Surveying treated me right for a project down there a few years back.

This all works as long as the monumentation on the ground is accepted by both parties, if there is a dispute it can get expensive. One thing I always make sure to do is to drive two steel pins at each boundary point. One sticking out of the ground and one driven about 6" deep. That way if one goes "wandering", the deep one is still there and can be picked up with a metal detector and reestablished.

 

[kettensäge]

Isn't this the neighbors responsibility?

Thought I saw a cheap transit at harbor freight last time I was there.

 

[semipro]

If you can buy or borrow a GPS unit that is WAAS enabled then it will be much more accurate (+/- a meter) than a standard unit. If you can get sufficient signal despite the trees you might be able to track the line using GPS. I"m pretty sure there's some free software out there that would help.

 

[homebrewz]

You might check your local zoning laws. There might be a buffer area or boundary required for such activities when they get close to property lines.

I had a prof in college that used to survey caves with a Brunton compass, and would often be able to close the loop within about 6", so it can be done.
Perhaps flagging 10' or 20' above one of the monuments vertically would help it be more easily seen from the other end? Perhaps establishing a tie point would help. Now, I'm not great with geometry, but I seem to remember transit operators using tie points, or making a triangle, when we would have to move the transit to another location.

 

[djblech]

I have a PLS 90 laser for setting up foundations. It gives you 2 90* vertical planes and has a detector that beeps when you are in line. That way you could hold it up and get a beep to keep you going straight. Good luck, I don't know many loggers that get to concerned about property lines.
Doug

 

[jebatty]

Good luck, I don’t know many loggers that get to concerned about property lines.

That's usually because the logging contract makes the landowner responsible to hold the logger harmless due to a cut across the property line, and the landowner is responsible to set that line. Treble damages for timber trespass can get expensive.

 

[pyper]

For a single straight line have you considered hiring a surveyor? Maybe your neighbor would pay part?

I marked my property line using a laser, but it was only about 200 feet and fairly clear. I measured out three feet from the two pins, pointed the laser from one to the other, and then measured back and set fence posts. No particular reason to do it, I just wanted to know where it was. No fence, just some metal posts.

At our new house the lady next door says that some guys doing some tree work removed the pin from the one corner. WTF? She points to a brick and says "It was near there." Trying to decide if I want to get a surveyor to come out and put in a new pin or just measure from the others.

We were looking at one house and the owner says, "It's my understanding that the fence there is 2 feet on my side of the property line." Doh!

 

[firefighterjake]

For a single straight line have you considered hiring a surveyor? Maybe your neighbor would pay part?

I marked my property line using a laser, but it was only about 200 feet and fairly clear. I measured out three feet from the two pins, pointed the laser from one to the other, and then measured back and set fence posts. No particular reason to do it, I just wanted to know where it was. No fence, just some metal posts.

At our new house the lady next door says that some guys doing some tree work removed the pin from the one corner. WTF? She points to a brick and says "It was near there." Trying to decide if I want to get a surveyor to come out and put in a new pin or just measure from the others.

We were looking at one house and the owner says, "It's my understanding that the fence there is 2 feet on my side of the property line." Doh!

Had a similar experience . . . actually two similar experiences . . . neighbor kid pulled up one stake since he apparently didn't know what it was . . . and the other neighbor bulldozed another stake when they put in a new driveway. Fortunately, before the one neighbor moved he replaced the stake . . . and on the other side it's pretty easy to see where my line begins due to the stone wall.

 

[homebrewz]

If your neighbor still gives you a hard time just tell him you're surveying because of the gas lease you just signed.

 

[RustyShackleford]

My neighbor isn't giving me a hard time. I think I can do what I want, within reason. But I am SOL on any damages due to the time that has gone by. I was unable to locate the iron that definitively shows the trespass until quite recently. I also located another of the neighbor's irons, and measured the distance to this iron I recently found (the one along the line between our two properties), and it jibes with the line distance in HIS deed. So I'm quite comfortable that it's the correct iron. I am told that irons in the ground ("physical evidence") trump most anything, around here at least.

I don't feel like giving him ANY property back on the flagging and line-cutting, so I'm gonna dead-center that as best I can. Of course if I do something permanent like a fence I will probably back off a few feet, as folks advise.

The idea of helium balloon is very clever; I thought of that myself I think it'd need to be about 100ft high, and couldn't quite figure out how to get a balloon big enough for that (I guess it'd have to be able to lift 100ft of whatever line I use). I don't think a bundle of party balloons would do it, but maybe ...

Where would I rent a WAAS-enabled GPS ?

Thanks for all your thoughts, folks.

 

[pyper]

If you have a laptop, you can get this WAAS receiver with software for $59:

http://shop.delorme.com/OA_HTML/DELibeCCtdItemDetail.jsp?item=31205&section=10122

It supposedly increases your accuracy to 3m.

 

[midwestcoast]

If you really want to nail it with GPS you can do much better than the WAAS accuracy. Trimble has handhelds that will get you sub-foot, even down to a few inches in real-time. Pricey though, maybe $75 a day for the real high end units.
I've rented from these folks for work http://www.compasstoolsinc.com Give a call & see if they have something user-friendly that would work for you. Start your rental on a Friday, I think weekends are free so 1 day is all you'd pay.

 

[jebatty]

A wrinkle once you are able to obtain accurate info is that the probability is high it won't match what's on the ground as to historical boundary lines, or at least where people thought the boundary lines were. So you may be "right" and "wrong" at the same time. If there is a discrepancy, you still have to deal with neighbors if your newly found line trips into what they think is their property; and if the line falls inside what you thought was your property, then you might want to "shut-up" and leave well enough alone.

I located what I believed to be close to a boundary line, and found that the line started close to where I thought one corner was, but the other corner 1/2 mile away that I located was about 75' on the other side of a fence line that I thought might be the boundary, but never was very sure due to other evidence on the ground. I contacted the neighbor 2 years ago, showed what I found, and so far at least we seem to be in agreement that what I found probably is correct. I promptly marked and cleared the newly found line.

 

[Prosecond]

All landowners should mark their lines with either paint on the trees or metal t posts. Can prevent a lot of problems in the future.

 

[semipro]

If you really want to nail it with GPS you can do much better than the WAAS accuracy. Trimble has handhelds that will get you sub-foot, even down to a few inches in real-time. Pricey though, maybe $75 a day for the real high end units.
I've rented from these folks for work http://www.compasstoolsinc.com Give a call & see if they have something user-friendly that would work for you. Start your rental on a Friday, I think weekends are free so 1 day is all you'd pay.

Unless I'm mistaken getting that level of accuracy requires that you either set up a basestation transceiver or make use of a nearby one to get "differential" accuracy. I hope I"m wrong. WAAS receivers however are real-time and require none of this. They use a 2nd set of satellites for correction data.

Also, even when GPS is not "accurate" it is relatively "precise". In other words, whatever error its reading at one location is likely the same error nearby so use it for relative location WRT a known absolute location.

If you have as many trees as it sounds like I don't think GPS is going to work anyway, especially after the leaves come in.

 

[WhitePine]

If you have as many trees as it sounds like I don't think GPS is going to work anyway, especially after the leaves come in.

Some units with a very good receiver will work in the woods even after the trees leaf out. I bought a particular Garmin because they explicitly stated it would pick up signals under the canopy. It works fine.

 

[WhitePine]

I've been looking at various state forestry sites recently. I noticed that some states strongly recommend or even require that buffer zones of uncut trees be left along the boundary lines when a property is logged. If you haven't already done so, you might want to check into NC's rules and see if they require buffer zones.

 

[semipro]

If you have as many trees as it sounds like I don't think GPS is going to work anyway, especially after the leaves come in.

Some units with a very good receiver will work in the woods even after the trees leaf out. I bought a particular Garmin because they explicitly stated it would pick up signals under the canopy. It works fine.

I guess it depends on the definition of "works". Accuracy of GPS is dependent upon a number of things and one is how many satellites are "visible" to the receiver and being used for location calculations. While the unit may give a location with several satellites, the accuracy increases as more satellites are used. I typically look for 7.

If you happen to use yours in the woods, I'd like to hear back as to how many satellites your receiver sees. It may be time for me to look into getting a new unit if they've improved that much.

Thanks.