Shop Products
Houzz Logo Print
sparksals

How accurate are Plat lines on GIS maps?

sparksals
15 years ago

I just looked at the plats online for our house. We will be putting up a fence soon and will have to get a survey. When I saw the plat, I found something that I never noticed before. The line btwn our house and the neighbour's is further over on the plat. It indicates that their fence, garage pad and a portion of their 2nd built garage are on our property. Essentially, the line btwn the houses ends on their driveway.

How accurate are these lines on these plat maps on the County GIS systems?

We were talking to the neighbour a couple weeks ago as he asked about the trees btwn his driveway and ours. He asked if we could have a collaborative effort to have them trimmed. We agreed and said we'd get together on a weekend in sept to do this.

He then mentioned that the previous owner came out screaming at him because he was trimming what she considered to be her trees. When he told us this, we thought that was silly because if they fall on his side of the property, then he can trim them however he wants, thinking that the dividing line was around the line of where his fence is. This fence was installed by the owners prior to them.

Now, I'm wondering if the previous owner knew about the property lines and that's why she freaked out on him. But then, why wouldn't they have done anything about the lines or notified us about it? Is this a disclosable issue?

See photo below. Our neighbour's house is the one with the red car on the left side of their driveway (when facing the house). Ours is to the left of them, again when facing the house.

Also, looking at our neighbour with the pool, it looks like their back line is further inside their yard, so I'm wondering if these lines are an estimate. However, when looking at all the other houses on our street, the lines look pretty accurate.

This misunderstanding of the line may be why we weren't able to find the pins using a metal detector to get an idea prior to having a survey done.

Finally, after we have a survey and it is discovered that the lines are correct and it is our property, how on earth do we approach the neighbour without causing a huge rift? They could be completely in the dark and have no idea. We certainly wouldn't ask them to move anything, but we would like to be compensated to have that part of the property transfered to them. Is that how it is typically handled? Otherwise, they would have to tear down their garage etc. We wouldnt' ask them to do that.

We're not talking inches here. We're talking about 5 or 6+ feet in width and the entire length of our property.

Comments (40)

  • cearbhaill (zone 6b Eastern Kentucky)
    15 years ago
    last modified: 9 years ago

    I wouldn't rely on that source at all- several of the properties look very much compromised.
    Get a good, certified surveyor and he can answer all your questions- he's seen it all before.

  • sparksals
    Original Author
    15 years ago
    last modified: 9 years ago

    Out of curiosity, how do they look compromised?

  • cordovamom
    15 years ago
    last modified: 9 years ago

    I have seen several homes where the lines were skewed for whole sub divisions, I don't think they're meant to be totally accurate. Rely on your survey for total accuracy and don't rely on the GIS plat lines.

  • lyfia
    15 years ago
    last modified: 9 years ago

    Did you not have a survey when you bought the property?

    I don't think the lines are accuarate on there at all. I see several lines that seems skewed for example some have less along the street than others. Some seem to own parts of the side walk on the other side (which I doubt). I would have expected the circle around the cul-de-sac to be even on both sides and not take hardly any front yard on one side and a lot on the other side.

    All the lines seem shifted towards the bottom and left of the picture.

  • sparksals
    Original Author
    15 years ago
    last modified: 9 years ago

    Lyfia,

    We do have a survey, but one wasn't conducted when we bought the house because it was the middle of winter with a million feet of snow. Honestly, I don't know how to read them anyway and from previous experience, we assumed the lines were close to the fences. There was also no easement/encroachment paperwork in the escrow docs and no disclosure of skewed lines.

    The first home I bought had an encroachment agreement. A part of the back fence encroached on the neighbour's property as a result of people building fences on what they *thought* were the property lines. We signed the agreement when we bought and disclosed it when we sold.

    The lines around the front of the houses are easements from the city. When I went to the city to get a copy of the survey I asked if we owned the property and they said we do, but that they are free to work on that portion for utilities etc.

    I can see what you mean by the skewed lines being different for some houses.

    We think that the previous owners of that house built the extra garage and perhaps there was a city code that required a certain amount of space btwn that and the property line. I don't know if the fence was built before or after the 2nd garage.

    I will certainly be contacting some surveyors and have someone come out as soon as possible.

    Another question - how does title insurance figure into this? My understanding of it is that it warrants against a situation like this, that we have a warrantee deed against such encroachment etc. If it's discovered that the property lines are similar to the plat, and the neighbour's become nasty, is this when title insurance takes effect?

  • sparksals
    Original Author
    15 years ago
    last modified: 9 years ago

    cordovamom - how do we read the survey? It's just a bunch of lines, measurements and I think lat/longtitude numbers.

  • etznab
    15 years ago
    last modified: 9 years ago

    The accuracy of the plat lines on a county GIS system vary from county to county. But they generally are not accurate for survey purposes.

    Not sure in other areas, but in NC title insurance will not cover boundary problems if you did not have a survey done prior to closure. And they will also not cover "shortage" problems without a survey such as you thought you bought 0.5 acre but actually only have 0.4 acre.

    Did the property owner actually tell you where the property boundary was ... or did you assume it was the fence line? If it was your assumption, it's probably not a disclosure issue.

  • cordovamom
    15 years ago
    last modified: 9 years ago

    Any survey I've seen has the footprint of the house and all it's measurements recorded, all the hardscapes such as patio, walkways and driveways measured and recorded, distances from survey markers to the road measured, and from side to side measurements of the property from marker to marker.

  • annie1956
    15 years ago
    last modified: 9 years ago

    Surveys are taken off of "markers" -if you find the starting marker on the survey. It will be at the beginning arrow of the square of your property line or whatever shape your property is. It should be noted where that marker is located - in subdivisions people buy permanent markers for their corners, if there are none the surveyor have to go back to a "known" marker. They they measure in feet to your corner. The degrees reading is off north. If you know your starting corner you can follow the arrown/feet down one line to the next marker. (Walk it out to judge it first to get the hang of it) Again - it will say what the marker will be for each corner. (If it was a fresh survey - around here they flag it). You may have a steel pipe in the ground for instance. It might take a little while - the two of you standing on each corner. Unless you have acres of land or a really convoluted shaped piece of property It's pretty easy to figure out.
    Good luck - and have fun.

  • theroselvr
    15 years ago
    last modified: 9 years ago

    Surveys are taken off of "markers" -if you find the starting marker on the survey. It will be at the beginning arrow of the square of your property line or whatever shape your property is. It should be noted where that marker is located - in subdivisions people buy permanent markers for their corners, if there are none the surveyor have to go back to a "known" marker.

    This is pretty much how it was done where we used to live. The land surveyors used to come out, pretty sure they started at a corner house, from there, they went to the last corner house, then measured in both ways. Our last house had a piece of wood IIRC as the marker but only on one side, the left side if you were looking at the house. There was nothing on the right. At the house I lived in before the other, it was a monument type, made of concrete.

    Finally, after we have a survey and it is discovered that the lines are correct and it is our property, how on earth do we approach the neighbour without causing a huge rift? They could be completely in the dark and have no idea. We certainly wouldn't ask them to move anything, but we would like to be compensated to have that part of the property transfered to them. Is that how it is typically handled? Otherwise, they would have to tear down their garage etc. We wouldnt' ask them to do that.

    We're not talking inches here. We're talking about 5 or 6+ feet in width and the entire length of our property.

    Is it possible to contact the old owner to see what paperwork they have?

    Chances are, his garage, etc are on his property. I'd assume they'd have to be very sure before they put up a structure like that. Typically you hear of sheds, fences or plants.

    I don't think there's an easy way to do it. Next time you see them, let them know that since you weren't able to get a survey when you bought due to the weather, that you're going to get one done. Possible that if they don't have one, they'd like to get one at the same time as well. Maybe they'd give a cheaper price as a two at once? Never hurts to ask.

    Once you get yours, then you can share the findings, if any.

  • jy_md
    15 years ago
    last modified: 9 years ago

    Lines on a map are usually just representational, that is, they are not the legal definition of property. Most places use "metes and bounds" to provide the legal description of a property.

    Looking at the picture, it seems like all the lines shifted and are distorted which is expected and unsurprising when you think about how a map is generated using GIS. Each feature (photos, boundary lines, sewer lines, etc.) is depicted on a separate layer. While they can be matched using landmarks and markers, aerial photos rarely (if ever) match drawn layers.

  • sparksals
    Original Author
    15 years ago
    last modified: 9 years ago

    Lyfia - I will dig out the survey and scan it. Now that I think of it, the survey I got from the city (we also have one with our escrow docs, but we're renovating right now, so things are a bit out of place) shows where the pins are. For the area in question, the pin is between the two properties around where the trees are. We couldn't find it with a metal detector because there's a fire hydrant and a metal lid close to it.

    etznab - It may be different in MN since it was impossible to do a survey with all the snow. It was the worst winter in decades and the snow was literally piled at least ten feet around the driveway from shoveling.

    So, what is the exact purpose of title insurance and a Warranty deed?

    This is where I learned a valuable lesson. When I saw the house, I did assume the fences were on the property lines as that is how it's been everywhere I have lived. When we buy our next home, that will be on my list of questions for the owner.

    Turns out the people beside us with the pool put their fence inside their line, the guy beside and behind says it's on the line and the people behind us have it inside the line as he comes around to mow the strip on our side when he mowes the lawn. It seems the previous owners didn't participate in any of the fences surrounding the property.

    Annie - thanks for that explanation. Our property is a tad convoluted. We have 5 or 6 markers on the property according to the survey. We think we found one pin marking the two properties behind us, but it was so deep down and we weren't sure what it looked like. We couldn't find any other pins with the metal detector because of chain link fences and our sprinkler system.

    Rose - When I returned the metal detector, they asked me if I found what I was looking for and I said no. Another customer said that sometimes people remove the markers when they install fences, sprinkler systems not realizing their importance.

    We don't have any visible markers at all. It could be the neighbour's fence post is over it, as it beeped, but that fence is chain link with the posts set in concrete. We were hoping to get an idea of the markers for building the fence, but then when I saw the lines on the GIS plat, I freaked out.

    They know we're building a fence as I asked if we could butt up to theirs and they said yes. I asked if their fence was on the property line and he said he didn't know as he's not the original owner and the fence was there when they moved in.

    I told him we were getting a survey and he said he'd be interested to find out the results. DH and I discussed if the fence is on our property, we will talk to them and suggest they get their own survey and then we can go from there. We wouldn't make them move their fence, but neighbour said he will have to replace it in a year or two. We would ask to put something in writing that the line be fixed when he replaces the fence.

    We're OK adverse possession wise because the time limit is 15 years in MN and our house was built in 1995. We will consult with a lawyer to be sure and to write something up so that both parties are protected.

    We also have the issue of the fence behind us. They did it inside their property line and this is the guy who mowes the strip on our side. He's clearly taking care of it even though we mow it too. We have no interest in taking his property, but when we build our fence, his access will be blocked. We will have to approach them to put something in writing so it is documented we know that the inches along the fence on our side belongs to them.

    I don't think they will make us build the fence straight across because then they won't be able to get in to mow it. We were hoping that we could go along our line and then do a slight turn to butt onto their fence.

    Our neighbours with the pool built their own fence along the back of their property even though the guy has a chain link. They can't get back there to mow and it's filled with weeds. I don't want that along the back of our property, but either way, once we put up our fence, their access will be blocked no matter how we do it. I have to think that since they put it inside their property line, that they should have anticipated a fence going up that would eventually block their access to those inches of property.

  • sparksals
    Original Author
    15 years ago
    last modified: 9 years ago

    jy md - I tinkered with the layers on the plat map and I did get the measurements from pin to pin. I think dh and I could measure from their fence to where we found what we think is a pin dividing the two properties behind us. That will give us an idea of if their fence is where it's supposed to be.

  • cearbhaill (zone 6b Eastern Kentucky)
    15 years ago
    last modified: 9 years ago

    "we assumed the lines were close to the fences."

    So did we, and we were wrong.

    After we moved in a neighbor came to ask us if he could trim some of "our" shrubs- 20 feet past the fence into his yard!
    Long story short we had a proper survey done, had the fence relocated and now enjoy another 20 feet of yard. We have five feet on the other side as well, but as having the fence moved is expensive we are putting it off.
    Many fences have no relation at all to the true property lines.

    When our surveyor came to drop off the final drawings he walked our entire property line with us and showed us each of his markers. We spray painted each one of them, plus various trees, rocks, and other landmarks (it's a large lot) and took many, many photos of each marker and line.
    It was well worth the money.

  • sparksals
    Original Author
    15 years ago
    last modified: 9 years ago

    Why on earth would people put a fence 20 feet INSIDE their property line? That's just opening themselves up for an Adverse Possession case.

    Thanks for the tips. We will do something to permanently mark them. Taking photos is a great idea!

    Glad the fence line work in your favour!

  • etznab
    15 years ago
    last modified: 9 years ago

    Sparksals - regarding your additional question on the purpose of title insurance, it's to protect against "defects in the title."

    When you buy a property, you assume that you are the only owner and no one else has a claim against the property. Title insurance protects you in case that assumption proves to be faulty. For example, let's say you bought a property from a "single" individual who lied about his martial status. If a spouse later appears, that spouse has a claim against the property. But title insurance would protect you. Or let's say 10 years ago, the original owner dies and willed the property in equal parts to "all my children" and today a previously unknown child appears who has an interest in the property.

    The title search that happens before closing is supposed to find "defects" in the title, which are quite common. But title insurance is your protection in case they don't find everything. And not everything can be found in spite of the most diligent search. In the examples I gave above, a title search should of discovered that the seller was married. However, there would of been no way to know about the additional child.

    Good luck. I'm having a dispute with my neighbor right now about property lines. No fence is involved but I tore out some rose bushes that apparently his daughter planted as a child. And it led to some very bad feelings. I did have a survey done prior to purchase so I know exactly where my property line is and there is no doubt that those flowers are on my property. But the property line is a funky shape and we actually own several feet of what looks to be part of their front yard. And even though there is no fence, most people,(including myself before the survey) would of assumed the property line would have been the driveway between the two houses; but it's not.

  • sparksals
    Original Author
    15 years ago
    last modified: 9 years ago

    Thanks for the explanation on title insurance. I figured it could somehow fit in to boundary disputes because the seller did not give clear title to the property if they knew that neighbours had a fence or something else on their property.

    Sorry for your situation. We are trying to avoid any hard feelings. From the pins denoted on the survey, it looks like the patch between the two driveways is split in the middle and the GIS is inaccurate.

    I did hear from one survey company already and he quoted $750 - $1000 max. I figure this is pretty reasonable for peace of mind. I'm waiting to hear from the other company I contacted.

    Here is what they said in the email they do:

    Our standard residential property survey includes the following:
    1) Survey the boundaries of the property and set property corner stakes at all corners (most corners we find are in the wrong position as they have been disturbed or moved by neighbors so we set new ones as necessary).
    2) Locate your house in relationship to the property lines.
    3) Locate the houses adjacent to yours on the cul-de-sac.
    4) Locate any encroachments onto or from your property.
    5) Provide a Certificate of Survey showing boundary corners, property dimensions, locations of houses and any encroachments, signed by a Minnesota Licensed Land Surveyor.

    Does this sound complete?

  • George Dorer
    15 years ago
    last modified: 9 years ago

    Consider asking the surveyor to set "permanent markers" or "monuments" - or if that is expensive - create your own using iron pipes - locating them where the stake was set.

    Place a large can around each pipe 2-3" below ground and fill it with concrete. This will make it easy to find in the future.

  • sparksals
    Original Author
    15 years ago
    last modified: 9 years ago

    Thanks for the tip, princeton. I'll ask the surveyors if they have a more permanent method of marking. We have nasty winters here and it would be very easy for the stakes to be removed or knocked over with the weight of the snow.

  • heimert
    15 years ago
    last modified: 9 years ago

    For inaccuracy, look at the house facing Danville Ave. (where hte street name is). Lines clearly are off by some distance where fences are. Perhaps their survey was wrong, but I would guess that the photo overlay and the property line overlay simply aren't perfectly lined up.

    As for stakes, any surveyor should put a metal stake/rod into the ground in addition to the wood stakes with flags that you can use for quick visual reference while building.

  • brickeyee
    15 years ago
    last modified: 9 years ago

    "I'll ask the surveyors if they have a more permanent method of marking."

    They are called 'monuments', and cost extra to have installed.

    Pieces of lead pipe are popular, though steel pipe is also used.
    They are often at least 2 feet long, or even more.
    They are driven to barely flush with the soil, and can be found by inspection (even easier if you measure first) or with a metal detector.

  • frog_hopper
    15 years ago
    last modified: 9 years ago

    Look at December Trail. In almost all cases, a road will go right down the middle of its right of way. Now look at the GIS boundaries on either side of the road. They aren't even close to being equidistant to the road's center line. That inidcates the GIS boundary representations are not very accruate.

  • etznab
    15 years ago
    last modified: 9 years ago

    The list from the survey company sounds very complete. Good points that other have made about getting more permanent markers. The only other thing I would suggest is on (#5) the certificate of survey, see if you can get more than one "original copy".

    Not sure in other areas, but in NC if you are ever in a legal proceeding that involves the survey work, you need the original signed and sealed paperwork; a copy will not suffice. Most (but not all) surveyors in my area will automatically give buyers two originals.

  • justnotmartha
    15 years ago
    last modified: 9 years ago

    One of the standard title insurance exceptions (where I like to play in it) is:
    Discrepancies, conflicts in boundary lines, shortage in area, encroachments, or any other fact which a survey would disclose.
    As we are not a survey state, this pretty much rules out property line issues.

    Title insurance is on a legal description. So, if they are insuring lot 1 of Fred's Subdivision, they are insuring you get lot 1 as platted. If the fence isn't where it should be . . . it's a tough luck kinda deal.

    A survey is completely worth it, if you ask me.

  • qdognj
    15 years ago
    last modified: 9 years ago

    Having done thousands of property surveys, i can tell you the plot lines you see from GIS system are not acurate..I am certain technology has gotten better since i "retired" in 2000, but the standard error is/was 9 ft+-, and that was field measurements,not office overlay..

    I would NOT pay for "monuments" as the cost is insane,go for iron pipes as permanent markers..And please DON"T do set your own corners with pipe after the surveyor placed stakes...You could really screw up future surveyors who find these pipes and think they are set by a surveyor,even being off 1" can really wreak havoc, as errors compound..

    If i can be of any further assistance,just let me know

  • sparksals
    Original Author
    15 years ago
    last modified: 9 years ago

    Heimert - The surveyor responded "As for the property corner stakes, we set 1/2 inch steel stakes 16" long in the ground and they will have my Surveyors License number in a cap in the top of the pipe as required by law. You won't have any problems finding them for many years to come unless someone actually goes to the trouble of digging them up.

    Sounds pretty complete and they will be easy to find. I will take a photo and mark with spray paint or something else until we can get the fence up.

    They could have come tomorrow, but I won't be home, so it's set for Monday when I will be here.

    etznab - thanks for that tip about the number of originals to receive.

    JNMartha - Ok, that makes more sense. You are protected that you get the lot as platted and documented, but dealing with fences on your property or boundary issues is separate.

    qdognj - thanks for that info! I was worried they would just put flags or something to denote the lines. Our neighbour behind is not happy we're building a fence b/c her kids cut through our yard to get to our neighbours with the pool. She had the audacity to suggest we put an invisible fence up instead. Ummmm no, I'm not going to electrocute my dog!

    Turns out, our yard is the pass through for many neighbourhood kids. None asked. I don't mind the kids behind and beside to preserve neighbourly relations, but we had to stop three different kids riding their bikes on our lawn!

    We were going to put up chainlink for budgetary reasons, then we heard that the kids would climb it anyway, so now we're going to the expense of a privacy fence.

    All the strange kids who cut through that we catch are told to stop cutting through. But, it's on a side of our property that we can't see unless we are outside, so I'm sure many still go through un-noticed.

    I will be VERY happy when this fence goes up.

  • qdognj
    15 years ago
    last modified: 9 years ago

    solution to kids that cut thru your property..Purchase a water sprinkler motion detector..I used one for just this purpose after all pleas for not cutting thru my property went ignored...They now have ones that hold a gallon of water and is solar, so no need for a hose to be connected...also good for shrubs that are being eaten by deer/rodents/rabbits et al

  • sparksals
    Original Author
    15 years ago
    last modified: 9 years ago

    Wow gdognj... that's a great idea!

  • sparksals
    Original Author
    15 years ago
    last modified: 9 years ago

    Just providing an update. We had the survey done by a very reputable company that's been a family business since the 20's. They bought the company when the original owner retired way back when and they have surveys dating back to the 1800's in their archives. It cost $1000.

    The results were very surprising. Our neighbours on the other side with the pool, their fence is encroaching on our property slightly in an area. It looks like the people who built their fence didnt' do a good job of following the line because most of it is inside their line, but about 6 ft' where it borders on the people with the chain link encroaches on us. We told them about it and said we're not worried about it, but if either of us go to sell, it has to be disclosed. We also asked that when they go to replace the fence that it be fixed to the proper lines.

    We're not worried about these people. We have a good relationship with them and we sent a copy of the survey to them certified mail to stop any possible adverse possession. They're just not the type, so we're not worried about that.

    The original area about which I was concerned with respect to the plat lines was interesting. Turns out, the pin on the back corner was in the wrong spot and the previous owner used that the build their sprinkler system. Turns out, a portion of the sprinkler is on THEIR property because the pin had been moved. The surveyors put it where it belongs.

    We haven't seen them to tell them about it, but we have every intention of doing so. If they want us to move the sprinklers in the spring, we will comply, but I don't think they will.

    So, interesting results. The area I was worried about WE are encroaching with the sprinkler and an area I had no concern about whatsoever, they are encroaching on us. The other two fences (the chain link and the back fence) are inside their lines.

    The surveyors left the hole open with the pins and then put in long stakes just in front so we can find them in the spring which should survive the winter. I'm going in for surgery and we won't get the fence done in time, so we'll have to wait for the thaw.

  • mfbenson
    15 years ago
    last modified: 9 years ago

    According to the GIS map in my county I "own" about half of a public street that runs across the front of my property. It is my impression that the map isn't even meant to be accurate and is just a representation.

    The actual plat of my property does seem to be accurate though.

  • qdognj
    15 years ago
    last modified: 9 years ago

    mfbenson, it is not unusual for a property's metes and bounds to originate from the centerline of a road..Particularly if you have an older home(greater then 40 years)..Very few newer homes do such...If the plat of your property is accurate,then i'll bet showing the road thru your property is also accurate..Unlikley, you own the road..

  • brickeyee
    15 years ago
    last modified: 9 years ago

    "We told them about it and said we're not worried about it, but if either of us go to sell, it has to be disclosed. We also asked that when they go to replace the fence that it be fixed to the proper lines.

    We're not worried about these people. We have a good relationship with them and we sent a copy of the survey to them certified mail to stop any possible adverse possession. They're just not the type, so we're not worried about that."

    Have an agreement drawn up that defines the intrusion and send it to them, certified mail, return receipt.
    This defeats the requirements for adverse possession since it removes the 'hostile' provision.

    You have indicated you are aware and grant limited permission for the incursion.

    Any decent RE attorney can formulate the letter to meet local requirements.

  • sparksals
    Original Author
    15 years ago
    last modified: 9 years ago

    Thanks brickeye... we will do that.

  • mfbenson
    15 years ago
    last modified: 9 years ago

    "it is not unusual for a property's metes and bounds to originate from the centerline of a road..Particularly if you have an older home(greater then 40 years)..Very few newer homes do such...If the plat of your property is accurate,then i'll bet showing the road thru your property is also accurate..Unlikley, you own the road.."

    The house is 30 years old - I don't know if that means anything. I don't get how the plat and the GIS map can both be accurate when they are different from each other? The plat does not show me owning the street, the GIS map does. Do metes and bounds carry different legal weight than actual surveyed property lines?

  • qdognj
    15 years ago
    last modified: 9 years ago

    I can assure you, you don't own the street,lol...And the fact your home is 30 years old also adds to that certainty...Sometimes when a deed starts its metes and bounds from the centerline of the street, that portion of property in the road is later deeded out, and conveyed to the town or county...A GIS map is never intended for exact property demarkation..

  • mfbenson
    15 years ago
    last modified: 9 years ago

    "I can assure you, you don't own the street,lol..."

    That much, I had figured out...

    "A GIS map is never intended for exact property demarkation.."

    Okay. I think we are all in agreement then. :)

  • SRSURVEY911_aol_com
    12 years ago
    last modified: 9 years ago

    the GIS is not to be used as property line deleneation these are visual aids!!!!!!!!
    you want to know where the property line is on the earth hire the professional that does that

  • sparksals
    Original Author
    12 years ago
    last modified: 9 years ago

    This thread is from 3 years ago and you will see I did hire a professional surveyor and the issue is long resolved.

  • mtvhike
    9 years ago
    last modified: 9 years ago

    If anyone is still interested in this issue from an old thread, I recently purchased some property and had to parse the survey description and I thought it was interesting. Here is the first sentance (specific references deleted for privacy):
    "Beginning at a found 3/4" iron rod in concrete 0.1' below grade located at the northwest corner of the herein described parcel and the southwest corner of (name of neighbors) as described in deed book xxx page yy, said iron rod being located on the easterly assumed road bounds of (multiple names of the road), said iron rod being also located S 20°-59'-01"W as referenced to New York State Grid North by 1983 Datum by GPS Observations a distance of 250.34 feet along said road bounds from a found capped iron rod located at the northwest corner of (name of neighbors again) and the southwest corner of (other neighbors names) as described in deed book zzz at page xx and shown on (name of county map) and running;"
    Then appears the distance and direction to the next survey point. Then there a sequence of similar descriptions , ending with "... to the point of beginning."
    Very legalese description, but you see that it depends on finding a specific iron rod, the location of which is referred to another iron rod.
    It also assumes that the referred deed books still exist (some court records have been lost in fires).
    When I noticed that the Zillow app on my iPhone shows what I guess are plat lines, I tried to locate some of the corners using that data. I could not find all of them, and some I found were off by up to 50 feet. I know that consumer-grade GPS coordinates could be off by that amount, but maybe the plat maps are also off.