How to figure out property line over hills/woods

[Josephm]

Hello all,
I was wondering if someone might be able to help me with a problem I have. I need to build quite a bit of fence on a new property and only the corners are marked with survey rods.

I contacted the surveyor and, for him to come out and stake it every 100 yards or so, will be costly.

I think I can get the straight, flat parts marked out myself. I am just trying to figure out how to get it placed correctly over a wooded hill.

I have thought about putting flares out at night at the bottoms of the hill and use a 1/2" degree accuracy sighting compass and rifle scope. That way, I can go to the crest of the hill and align myself with the compass until I am dead center. Once I am dead center, the compass should read the correct bearing that is listed on the survey, when the light is in the crosshairs of the scope. This is all assuming there wont be too much brush in the way etc. to see the flares.

Does anybody know of any tricks for this? I am not sure if my idea will work or not. I really don't care if I am off a couple of feet in either direction, but would like to get it somewhat accurate.

Thanks,
Joseph

 

[2manyrocks]

What's your cost if you build the fence in the wrong place?

Are there any points of reference in your neighbor's deed to go by that would fill in the points besides the two rods at your corners?

 

[brin]

I have always made absolutely sure to build the fence on my property by at least 8 inches or so...to be sure that if my neighbor ever sold or their was a dispute he could not just arbitrarily tear down the fence or otherwise change or damage it. You might want to take this into consideration on the importance of being sure it is on your property . Call several surveyors and get the last survey that was done and tell them you just want a few markers. In the long run you will sleep better.

 

[ToadHill]

The easiest way is to contact your neighbor and the two of you can work out the line.

The neighbor and I used the tax map, agreed on the corner and used a compass to plot the line. One of us stood at the corner and the other walked as far as we could see with a stick. The person at the corner shot an asmith with the compass and had the walker move until the stick was in the right point.

The shooter then walked to the stick and set out markers along the way. Then we switched jobs and repeated the process until we reached the next corner.

We went through aver 2800 feet of woods and missed the second point we had agreed on earlier by less than 8 inches. We both agreed that was close enough.

 

[Jstpssng]

Hello all,
I was wondering if someone might be able to help me with a problem I have. I need to build quite a bit of fence on a new property and only the corners are marked with survey rods.

I contacted the surveyor and, for him to come out and stake it every 100 yards or so, will be costly.

I think I can get the straight, flat parts marked out myself. I am just trying to figure out how to get it placed correctly over a wooded hill.

I have thought about putting flares out at night at the bottoms of the hill and use a 1/2" degree accuracy sighting compass and rifle scope. That way, I can go to the crest of the hill and align myself with the compass until I am dead center. Once I am dead center, the compass should read the correct bearing that is listed on the survey, when the light is in the crosshairs of the scope. This is all assuming there wont be too much brush in the way etc. to see the flares.

Does anybody know of any tricks for this? I am not sure if my idea will work or not. I really don't care if I am off a couple of feet in either direction, but would like to get it somewhat accurate.

Thanks,
Joseph

how good are you with your compass? If it's good to within 1/2 degree, it must be a pretty good unit.
Your survey should give the bearings between the corners. Get a roll of florescent flagging tape and hang a strip directly over the first corner. Walk away on the bearing until you are almost out of sight of your flagging, then sight back to the corner, moving until you are exactly on line.Hang another piece from a tree there as close to where the line should be as possible, then go out and do this again. Repeat this process until you get to the next corner. Sometimes, especially if you're going uphill you can see the some of trhe flags farther back and adjust accordingly.
Hopefully you will be right on target. If you are within a few feet, you can then work your way backwards using the same process until the 2 lines come together.

Because you're actually sighting on something,backsighting is much more accurate than sighting forward and trying to hang the ribbon right on line.

Because of local attraction, minute errors in compassing, etc; the oldtimer that taught me how to ribbon a line did it this way. He used to say "I keeep telling you, a compass line wavers through the woods."

good luck

 

[dodge man]

I happen to be a surveyor and to be honest, none of the methods that are being described are that accurate.

First thing is how are the bearings on the survey done? Sometimes these will be based on what you would get with a compass and sometimes not. A good way would be to try the bearing on the survey, walk towards the corner and see how close you get. The rule with the compass is "always ahead, never back". You work on your forward bearing and never look back. The way I do it is to look ahead as far as you can see and pick out an object, such as a tree. Then walk to it without taking your eyes off it. Then keep doing this until you see how much you miss the corner by. Then adjust your bearing and try again until you get a bearing that is close to hitiing the corner. This may take several trys.

I think you will find that this method may take alot of time and may not be that accurate. You will also need a good surveyors compass that has a good sight on it, you are probably talking a $60 compass. If I ran the line for you with a compass, and I'm good at it, I wouldn't tell you I was any closer than 10' and any given point if the line is a half mile or longer. The truth is I would probably be better than 10', but there is no way to no for sure. If you aren't good at it, you could be off more than 10' really easy.

There is a reason that is expensive for a suveyor to do it, it takes alot of expensive equipment and calculations.

BTW if someone tells you to use a handheld GPS, IT WILL NOT BE ACCURATE ENOUGH. It will not be any better than a compass and most likely worse.

 

[/pine]

this may not be conventional...just an off the wall idea...
You did not say how high the hills is but something you might try is (considering you are not opposed to working at night) is to employ some lasers...
If you have a laser (exactly) at both corners and point them at each other it should give you a line (if not obstructed)

using a third laser leveled (so the beam is vertically plumb) anywhere under the beam will locate points anywhere on the property line

BTW...most tool rental outlets rent laser levels etc...

 

[dave1949]

I would also recommend using a builders level. Set the tripod up so the corner stake is under the plumb bob. If you have a survey with degree markings on it, you might be able to make use of those.

At least you can sight a good distance in a straight line. If you have a helper, they can put ribbons on the line. You may still have to do a couple iterations to get it right, but it will be more accurate than a compass.

There are good deals to be had on the older non-laser surveryor's transits which are pretty good tools. Some have digital degree readouts even for the rotation.

Dave.

 

[Josephm]

All, thanks for the replies. I was planning on getting about an 80 dollar sighting compass (spec'd accuracy is 1/2 a degree with 1 degree scale on the dial).

I have sort of a challenging situation. The run that I am going to have trouble with starts on flat land. Then it goes gradually about 30 ft down into a gulley and 40 feet back up. Then, it is flat for about 10ft and there is a 100' drop off into a river bank on the other side. The overall length of the run is probably less than 1000'. If I would just have one stake at that 10' flat area, I think it would be much easier.

I have also thought about putting a target down at the stake at the river. Then putting another target at the other side (the stake on the other side of the gully) and try to shoot 2 parallel lasers both directions until I can hit both.

However, there are alot of woods, but they are not that thick. I would have to do some minor clearing before attempting anything with a light or laser.

If I could somehow get 2 lasers and mount them so that they are exactly parallel with each other, I was thinking I could mount them on a plate that could swivel either 45 degrees so I can shoot downward toward each target.

Does anyone have any idea on how successful that attempt might be? Again, I am not looking for exact placement, I could tolerate a several feet deviation - I am not that concerned about the neighbor on the other side protesting anything since they are not splitting the cost of the fence with me - that is a whole other subject ).

 

[Josephm]

Another thing I thought of is just walking it with the good compass. Then doing it multiple times. At some point any inaccuracy would average itself out, I would think, unless it is some sort of fixed inaccuracy like a broken or miscalibrated dial on the compass.

I have another 2000' stretch that is flat and the stakes are in plain sight. I was thinking about testing the compass on that, and adjusting any "fixed" error out....

 

[Josephm]

Dave1949, I like your idea. I could setup a laser level on one of the stakes and adjust the shot with the compass. Then, set a marker as far as I could get, then setup there and move on until I get to the other stake. Then, maybe do that a couple of times, like you said, and average out any errors.

 

[Josephm]

OK, I think I have come up with an optimal plan sitting here thinking after reading all these posts.

Since the 10' flat part between the river bank and the gully is the highest point, I need to target getting a reference stake there.

Here is my idea:

1.) Setup a laser level at the 1st stake on the flat land on the other side of the gully. Shoot the survey bearing with the good compass up to the 10' area and mark it with a stake.
2.) Go down to the stake at the river and shoot the bearing backwards up to that 10' area and mark it with another stake.
3.) Split the distance between the 2 stakes and reshoot from both locations and see if I can hit the new "middle/averaged" stake from both the flat area and from the river bank.
4.) Maybe have to do several iterations to get it dead-on?

Seems like this should get me pretty close.

Any inputs on this idea would be greatly appreciated.

Joseph

 

[dave1949]

That sounds like a plan. If you have a builder's transit that rotates and the degrees are marked, and that property line is straight. You might be able to get in position on that 10' wide bench and sight in both directions by turning the transit exactly 180 deg.
I know the surveyors around here do a lot of bush whacking and approximate ribbon ties before they are sure they have the actual line. We have up and down heavily wooded terrain here too.
Dave.

 

[Egon]

What declination will you set your compass to?

 

[Jstpssng]

I happen to be a surveyor and to be honest, none of the methods that are being described are that accurate.

First thing is how are the bearings on the survey done? Sometimes these will be based on what you would get with a compass and sometimes not. A good way would be to try the bearing on the survey, walk towards the corner and see how close you get. The rule with the compass is "always ahead, never back". You work on your forward bearing and never look back. The way I do it is to look ahead as far as you can see and pick out an object, such as a tree. Then walk to it without taking your eyes off it. Then keep doing this until you see how much you miss the corner by. Then adjust your bearing and try again until you get a bearing that is close to hitiing the corner. This may take several trys.

I think you will find that this method may take alot of time and may not be that accurate. You will also need a good surveyors compass that has a good sight on it, you are probably talking a $60 compass. If I ran the line for you with a compass, and I'm good at it, I wouldn't tell you I was any closer than 10' and any given point if the line is a half mile or longer. The truth is I would probably be better than 10', but there is no way to no for sure. If you aren't good at it, you could be off more than 10' really easy.

There is a reason that is expensive for a suveyor to do it, it takes alot of expensive equipment and calculations.

BTW if someone tells you to use a handheld GPS, IT WILL NOT BE ACCURATE ENOUGH. It will not be any better than a compass and most likely worse.

You must have had a different survey instructor. We actually were taught to use front AND backsights, then average.
However, the old timer I used to work with taught me differently. Because I sight on a known point on the line, and each ribbon is tied as close to the line as possible I can get good accuracy.
If you are sighting forward you aren't dead on line; the tree or landmark may or may not be dead on; so you are adding 2 potential errors for each sighting.
No, it's not total station quality; I can only get as good as the tool; but for timberland applications I'm pretty close.

 

[dodge man]

Joesphm, your last plan sounds the best. If you were using a surveyors total station, its called "wiggling in". You basically set the instrument up, sight one corner, then turn 180 degress and see how much you miss the other corner. Then you move the gun and do it again until you hit it right on the money. You don't have that long of a line so you may have pretty good luck with the compass and practice with it some.

I'd probably tell you to stay away from using lasers, the problem being how do you get two lasers to line up and shoot a straght line. Maybe some of the ones used for home building have that ability but then how do you aim it up and down and hold a line. The range may be limited also, but if they had the range it might be a good check.

The way a surveyor would do it is set up a total station at a random point somewhere in the middle, shoot both corners and them calculate points on the line. We have a hand held computer called a data collector that allows for these calculations without alot of thought on the operators part. The random point can be anywhere, it doesn't have to be on the line. If it takes more then one random point, its called a traverse and I have done surveys that have several traverse points to complete a survey.

To give you an idea of cost, we charge about $120 an hour for me and a helper and I am a licensed land surveyor. The job you describe would maybe take as little as an hour once you got to the job site and set up. We charge for travel time and you might have to hike into the job site. If it was close to the surveyors office it might be as cheap as $200-$300. If there was some travel time, it could easiely get into $600-800. This is all assuming that I was the one that did the original survey. If I did the work all the points I set would be within 1 inch of the line.

The answer I should tell you is to hire a proffesional to do the work, but I have seen alot of people try much harder surveying tasks than you are talking about.

Fence builders probably have some good ideas on how to handle the problem also. I know they use string lines where possible.

Good luck and I hope this info helps.

 

[Jstpssng]

What declination will you set your compass to?

If he's buying a "Suunto" it won't be adjustable.He can go to Noaa and find out the difference between now and the date of the survey, though.

 

[dodge man]

I'll say it again, the plat may or may not say what the basis of bearings are. DO NOT count on a compass giving you the same bearing as the plat.

 

[caver]

If you are surveying at night and using a headlamp,,,it can throw your compass off. When I cave survey, I use something like a Suunto KB14. I always remove my helmet and lamp and hold it about 12" away as it will cause error in the compass.

 

[Josephm]

All thanks for the replies. I really appreciate the help!

Dodge man - I will take note about the bearings on the survey possibly not matching the compass bearings. One thing I do have going for me is that 2000' stretch (open, flat pasture) that (according to the survey) lies in the exact bearing with the other stretch I need to figure out. So, I think if I practice on that 2000' section that is out in the open, I can figure out any descrepancies with between the compass bearing and the survey. Then, I can account for that on the compass setting.

As for declination, the compass I am planning to buy is supposedly declination adjustable, so I think I should be good.

Thanks again for all the help!

Joseph