How accurate is a property line survey?

[Paddy]

Mike,

Surveys can be accurate but descriptions can be way wrong. Or better yet, over lap with adjoining lands. I have a friend that had an issue. There was a 30' overlap forming a triangle. My friend's land was previously owned by the county surveyor! No mater how far back they dug, they could never find the source.

The classic point of contension is on old property. Ol' grandad had 40 ac and kept giving 5ac to each of his grand kids. By the end all the pc don't "add up" to the 40. Last grand kid has some over lap with the neibor.

I had my land surveyed a few months back after owning it for 25 years to sell. I gained 15' by 660' !! Nearly 1/4 of an ac. I was selling the land for $7500 an ac so it paid for the survey.

Patrick T

 

[Tig]

Our county has a "fence arbitrator" he can be called in to decide what kind of fence is erected, where it goes and who pays for what. You may want to check your bylaws to see if anysuch thing exists.
Also the advice of checking bylaws to see what the rules are for stone fences is very good. There may be a setback that does not allow a stone wall within 3" of the property line.
This isn't survey advice but it is stuff that can be done for free. I hope it helps.

 

[swines]

Survey GPS is very very accurate because surveyors use Differential GPS (two GPS units. One on a known point which measures the error on the known point and applies that error to the point being measured.)
Zeuspaul.

Surveying with GPS may be accurate to plus or minus two centimeters. However, like any piece of equipment, it is subject to operator error or operator precision.

Differential GPS relies on a base station setup on a fixed (surveyed) point. It compares the known point programmed into it, to the location it is calculating from satellite information. It sends a correction factor to the mobile field survey unit so that the positional error is nulled out in the recorded GPS data.

Location errors come from the number of satellites available and atmospheric conditions that cause propagation delays in the satellite signals. The maximum number of satellites available (if you could see from horizon to horizon) is 11. But, in many cases, for periods of up to 10 minutes, there may be only 4 available. You need a minumum of 3 to establish location, and 4 will give you an indication of altitude. But, until you get to about 6 satellites you cannot consider the data to be accurate.

Many times the survey crew will not look at the satellite calendar to see how many satellites are available when surveying. They just take the antenna, place it over the point to be surveyed and (hopefully) hold it plumb (more about that later). Low satellite count can affect accuracy.

Precision also depends upon the accuracy of the base station location survey point; and then there are some factors that come into play that seem innocuous, but can greatly affect the accuracy. For example, the real location point for the base station (or field survey unit) is the antenna.

For the base station, let's assume that the surveyor took the time to drop a plumb bob from the bottom of the antenna tripod to the center of an accurately surveyed monument. Sounds about as accurate as could be expected.

However, let's also assume he did not take the time to level the antenna (or hold the field antenna plumb). There will be an error in the location as the actual antenna location, when a point is projected through the center of the antenna to the ground, will show the antenna to be displaced by the height of the antenna from the ground and angular tilt. This can easily give a positional error of 2-3 inches - or more if the both the base station antenna and field unit antenna are tilted when locations are being read.

There are other considerations like how many places can be programmed into the base station (degrees, minutes, seconds, etc. or decimal degrees - and to what place) that will affect accuracy. You cannot interpolate more accurate data than what is being generated by the base station, it's location, and how it has been programmed.

Lastly, if the surveyor is using a differential service (delivered via phone, satellite, etc.) instead of his own base station, there are a number of other potential sources of data errors if those sources are not take into account.

While GPS sounds like it's totally foolproof, it is no more accurate than the person operating it.

 

[AMR]

wow, this take me back, I am a civil engineer and took surveying in college, I work a lot with survey firms doing developments, buildings, etc., I am no expert but:

Generally, here in CT the A-2 survey is the standard survey for property lines, its level of accuracy is 1 in 5,000, or 1' in 5,000', in actual practice a typical traverse will close at 1 in 35,000 and frequently 1 in 75,000

When I was building on 9 acres here in CT the neighbor called up the town to say that I over excavated on his land, the town never even called me, they just went out and surveyed themselves and solved the issue with the neighbor

 

[zeuspaul]

For the base station, let's assume that the surveyor took the time to drop a plumb bob from the bottom of the antenna tripod to the center of an accurately surveyed monument. Sounds about as accurate as could be expected.

For a property survey let's hope he did a lot better than that!

Optical plummets are now generally used by surveyors. They are more accurate than plumb bobs. Hopefully two base stations are used on two known points and hopefully the rovers are also set on tripods and plumbed the same way.

We would also hope the data is returned to the office for post processing with closures less than a centimeter.

Zeuspaul

 

[WTA]

Sometime soon, I will be in a fight with a neighbor and it's going to be ugly.
The land in question was homesteaded over a hundred years ago by my family and is now going to me in the near future. I've caught one neighbor fencing off and using about 20 or 30 acres of it before and told him to get out. Even took his fence out and moved it once. He's a moron. That old place has been nothing but problems with neighbors in the past from them vandalizing and burning things to using our land. The worst problem is since it's not in my name yet and my mother won't listen to me about the neighbor then it will probably end up in court with him claiming he's been using it for years so it must be his by the time I am able to take action.

Here, our property line had pecan trees planted just inches inside it about 25 years ago. Now they are a few inches over the line and I need to put up a boundary fence there. I have a good relationship with this neighbor I guess and his land is in CRP so I was thinking about offering to buy a couple feet of that side of his property from him. Maybe 2 feet wide by 1000 feet long. That should cover us in case something happens to him and a developer gets it in the future. I just hope he will sell it to us. Those pecan trees are part of my income every year. I'd hate to have to cut them all down and replant.

I thought about putting T posts and high tension wire there, like I did all the pastures, then just wrapping the wires around his side of the trees but that sure will look funny. It will keep the neighboring livestock out though. One thing that really sucks about having the nicest pastures in the area is that everyone elses cows and horses are constantly breaking out of their properties to come over here and eat. I caught a sick horse in with mine a couple days ago from a guy about a mile up the road. I had to call the sheriff to get it. The owner better hope mine don't get sick now.

Oh, speaking of surveys being wrong. Have any of you ever seen one with antiquated old measurements? Cubits and such. Also things saying stuff like go dead North from the forked oak tree with a bullet hole in the left fork to the large moon shaped stone placed 12 inches NE of the burned our cedar tree. That's what we have to deal with on the old farm. There are steel post markers there now also but the deed was still worded just like original last time I saw it.
We had a 400 acre place in Pa that was the same way but had a very irregular property line so it was several pages of things I didn't understand.

I'm glad our place here is a simple square mostly and is marked clearly.

 

[swines]

For a property survey let's hope he did a lot better than that!

Optical plummets are now generally used by surveyors. They are more accurate than plumb bobs. Hopefully two base stations are used on two known points and hopefully the rovers are also set on tripods and plumbed the same way.

We would also hope the data is returned to the office for post processing with closures less than a centimeter.

Zeuspaul

I understand all of that - I was using a worst case scenario to illustrate what could happen; and how GPS surveying is not just setting up the equipment and taking readings. (It's not automatically accurate just because it uses GPS.)

I had a Trimble base station and kinematic receiver on a prototype land mine detection vehicle, and had to do all of the GPS work for that system - we used a 3-axis, inertial guidance system built from three fiber optic ring gyros to null out tilt and azimuth movement induced position errors as it was being driven.

And yes, I had an optical plummet to setup my base station....

 

[CurlyDave]

I've caught one neighbor fencing off and using about 20 or 30 acres of it before and told him to get out.

I hope you told him in writing. Unless you have a copy of a letter you sent, he will claim he was never told anything. If you persistently keep telling him, in writing, to not use your land and maybe get a lawyer to write a letter or two for you, your defense against an adverse possession claim will be much stronger.

 

[RobJ]

The big problem I see that Tractor888 has is that if he is sued, a common outcome of this type of suit is that the parties are ordered to share the cost of a fence on some court-determined property line.

I can't believe this. Even in a residential subdivision fences are optional and are put up for privacy only. some of our neighbors have no fence and don't have to go in halves. I'm not a rancher but I believe in Texas if I want to keep YOUR cows out of MY property...I have to put up a fence. Cows have rights you know!! I remember this because it's arse backwards.

Only case I've seen otherwise is the bordering fences to a street or the neighborhood boundary. Then in most cases the civic assoc or the neighborhood as a whole bears the cost. This of course would be in the deed restrictions.

 

[chadincolo]

I can't believe this. Even in a residential subdivision fences are optional and are put up for privacy only. some of our neighbors have no fence and don't have to go in halves. I'm not a rancher but I believe in Texas if I want to keep YOUR cows out of MY property...I have to put up a fence. Cows have rights you know!! I remember this because it's arse backwards.

Only case I've seen otherwise is the bordering fences to a street or the neighborhood boundary. Then in most cases the civic assoc or the neighborhood as a whole bears the cost. This of course would be in the deed restrictions.

Yep, most western states are free range states. It's your duty as a landowner to keep animals off your property if you don't want them. If you are driving down the road here in Colorado and hit a cow, you owe the owner the cost of the cow and you are responsible for your damages...no arguement, no question of why the cow was there. The State puts in and maintains (officially, courtesy is that if you have cows along the highway, you take care of the fence along the highway) all fences along all state and interstate highways to keep cows off the highways.

Fencing and property lines are VERY MUCH dependant on where you live. Here, it's common curteousy to maintain the fence on your right as you leave your property, but not a requirement. You would never think of putting a fence just inside your property line. The fences are the property line.

There are no "bylaws" or fencing boards or township governments for the area as some said there is in their area. A township here is 36 square miles that has one section that was orginally deeded to the local school, nothing more, no board or governing body, and may only have 2-3 landowners in that area...much different rules and common sense apply than areas where a square mile may have 30-50 landowners...