Based on what TomT226 told me re:92246.22 I found a friend of a friend who has a metal detector. I was going to rent one but glad I didn’t waste the time or effort. It seems there’s a little more talent-experience involved than what I envisioned.
So we roam the property at all the known points and came up with zilch. Nothing conclusive was found other than my concrete marker that I already knew of and the neighbors underground phone service. The phone service was obvious due to the surface mounted plastic cover that says -phone- but what I got a chance to learn was what a magnet sounds like using the detector. As far as detecting any rebar or any other iron objects nothing set off the alarm. He did show me what they sound like. I should also mention that we scanned an area of at least 50-75′ surrounding the known property points. He tried numerous different sensitivity settings too and still couldn’t confirm anything. After this little escapade I’m glad I let someone with experience do it.
He then suggests using GPS. He knows of some guys in the biz that use GPS and that they can walk into an empty lot dial in a few coordinates and start driving stakes at exact points. OK so I call a local surveyor and inquire about having a survey done by GPS. She says she subs GPS work out, but the accuracy wasn’t very good. She said the correct way is to enter the property info into a program to calculate distances and points and then shoot them off that.
Huh??? I thought GPS was as good as it gets when it comes to dead nuts accuracy? Is she feeding me a line so that she can do the survey in house or is the GPS accuracy really questionable? which I find hard to believe!
Thanks
Replies
civilian gps is within twenty feet
20'???So how does geocactching work then? I thought you needed exact numbers to find the stash
i don't know about gps,but the metal detectors are worthless. i don't think mine good find a army tank in the middle of the desert.
i swear everytime i use it i'm going to trash it,but for what i paid for it i hang it back on the wall,till next time. larry
hand me the chainsaw, i need to trim the casing just a hair.
"but the metal detectors are worthless"So I see. I was going to rent one but glad I didn't. The unit this guy had was supposed to be a quality model? He uses it for a side biz seraching for property line pins
i don't know about gps,but the metal detectors are worthless. i don't think mine good find a army tank in the middle of the desert.
They're great for finding the thousands of spent shells on any piece of property.
Joe H
I guess it depends upon what your definition of "accuracy" is. From a Federal Highway Administration bulletin from 2003:"GPS can provide a very accurate digital map of the
highway infrastructure. The technology operates on the
principle of triangulation—if the difference from an
observer to three known points can be measured, the
position of the observer can be calculated. The system
includes at least 24 satellites in orbit 19,320 kilometers
(12,000 miles) above the earth and inclined at 55°.
These satellites continuously broadcast their position, a
timing signal, and other information. By combining the
measurements from four different satellites, users with
receivers can determine their 3-dimensional position,
currently within 4–20 meters (13–66 feet)."http://www.fhwa.dot.gov/resourcecenter/teams/construction/cpm_5gps.pdf
Yep, it depends on what you define as accurate. When it comes to my property line, within 20-66' ain't accurate.George Patterson
All our new survey plans are created using gps. the surveyor does have to input the coordinates for any existing plans that you are overlapping. if you have an existing survey plan, its not to big a deal to input the coordinates, but the advatage to gps is a 1 man survey crew, and the ability to relocate points without a marker left behind (or a marker being removed)
Note - I'm not a land surveyor, but i do hire them quite often.
I have an A2 survey but I'm not sure if the needed coordinates are listed. For example it states: N 87* 44' 05" E; 513.19'Would that be what is needed for GPS or would the local townhall maps have that info?
I'm not sure if the needed coordinates are listed. For example it states: N 87* 44' 05" E; 513.19'
Would that be what is needed for GPS or would the local townhall maps have that info?
Probably some clarity in terminology is needed here.
Now, just about every municipality with more than two employees in its Planning & Development Department is busy entering plat date into a GIS system. For some muni, the emergency services may be required (or require themselves) a GIS-based dispaching system.
Note that is GIS, a Geographical Information System, not GPS, a Global Positioning System--although one can be used to collect data for or from the other, jsut to keep it good an confusing.
Now, a GIS is a way of recording all sorts of spatial information as a numeric database. And, that's all it is, ordered tables of numbers and text strings, with middling consistent Key tags to simplify data searches. Now, with the investment in some not-at-all-cheap software, you can key in boudaries that are defined in the variously accepted ways, which "converts" graphical data into numeric data. These systems also allow conversion of numeric data into certain kinds of graphical data.
Now, we've been also busy gridding out satellite imagery, too. A person can, numerically, get the satellite grids to mostly align with numeric plat grids, but, generally you have to tolerate a pretty good amount of "fuzz" in how that happens. Sat map to muni GIS generally close to around a meter plus or minus. That's plus or minus 3'-3+"; or a maximum of about six an a half feet, worst case.
Now, surveying is generally accepted to be to much higher tolerances than that. Usually measurements are to second-of-arc and 1/100 of a foot. A hundreth of a foot is close to an 1/8th inch to put that in perspective.
Let's look at your quoted value. N 87º44'05" E 513.19' Means, from some defined point, swing an arc 87.737222º east from True North, for a distance of 513'-1.44" exactly. Now, if we know how to describe the first point, we can pretty precisely set the second. Even better, as we traverse the points of a polygon, it the last sight "closes" on the first point, then we have very accurately defined a set of boundary points by observation.
Now, the Lowrance GPS unit I may or may not have laying about will spit out, by comparing the signals of about a dozen satellites, a coordinate in three dimensions that is accurate to one meter, about 18"± round numbers. With some math upgrades, and by monitoring satelites over a known time frame, this drops to the decimeter range. My handheld Magellan 315 tracks 10 to 12 satelites, and uses time comparision, and a math upgrade, to "beat" the "3 meter" "non military" signal off of the satelites (3 meters is about 20'). My handheld unit is good to about 1.5m, or about the width of my ride--which is good enough for eye-open land nav.
Ok, so wrap al lthis triva up, windbag. The one-man survey units use a laser and a gps-reading RF sending unit so that the laser theodilite can track the reflector-carrying person. Since the instrument "knows" about where the dude toting the target is to a yard, yard and a half, it need not make any wide "scan" swings to search for the reflector. Smaller movements mean less motion on top of th tripod, which mean better accuracy. But, the accuracy is coming from the strength of the laser signal the insturment is tracking, not the precision of the "here I am" GPS information--which will display to some scary precise decimal places.
So, we'd (somebody'd) need the complete description of metes and bounds for your property. Property surveys always start from a known point of beginning. That point can be set to some precision of lattitude and longitude. A bit of ciphering could then be used to make each of the bearing-distance pairs into waypoints which could be set into a handheld unit as a defined route. Why would you do that? Well, If we are going from the 6th to the 7th point on the boundary, and there's a great huge thicket in the way, you can go around the thicket, and the GPS will give you the direction and distance back where you are suposed to be, without having to hack a line of sight and a man-path through the thicket.Occupational hazard of my occupation not being around (sorry Bubba)
shazzam!! Had to read it a few times to let it sink in but I think I follow you. I even searched some of what you said just to understand it better. "But, the accuracy is coming from the strength of the laser signal the insturment is tracking"If the strength of the laser is what allows for minute accuracy is it possible to amplify the signal? >>just thinking out loudThanks for the truly informative answer. Looks like I need to bite the bullet and pay the freight for a survey. I tried to short cut the expense by searching for the iron pipes, but it was a wasted effort. It isn't quite as simple as it appears.
If the strength of the laser is what allows for minute accuracy is it possible to amplify the signal?
Well, HP and similar laser theodolite makers spend dollars galore coming up with proprietary methods to answer that question "better" than the next instrument maker does (or, at least so advertise).
My last understanding was that a prism is used to scan a wedge for any retuen from the reflector. That gets doppler-tested until the strongest signal is recieved. (Said task running in millisecond time-span.) Once the signal is locked in, then the precison "shot" is dialed in (which can be set, if memory serves to what you want the measurement recorded to (like 0.001± feet or 0.1± seconds of arc or what have you).
Thanks for the truly informative answer. Looks like I need to bite the bullet and pay the freight for a survey. I tried to short cut the expense by searching for the iron pipes, but it was a wasted effort. It isn't quite as simple as it appears.
Well, you do generally have to be "close," and the real world is resolute in not resembling "close" even at fourth & fifth glances. The "trick" of it might be in getting a hundred foot tape out (and a helper), and see if you can make the dimesnions "jibe" from paper to 'reality' as a starting point. So, if there's a note for 40' drive, you could measure out to there, than take a stab at finding the next nearest corner you can. You'll want a cheap calculator, a $10-15 hiking compass, and a google for what your local magnetic declinations might be (so that you're not 12-15º off kilter to start).Occupational hazard of my occupation not being around (sorry Bubba)
we tried the "trick" measuring from the concrete marker and nothing was found. This was an clear straight and easy site line and should have at least been simple to locate. Yeah right nothing is simple I quickly learned when it involves surveying. This corner isn't really questionable or a problem and who knows maybe this iron pipe got tossed when the finish grade and driveway were done.Maybe I'll get lucky and she'll need to locate this corner to find the 2 I need without any additional costs to me.
So, piece of property I used to own had a Cadastral Survey marker at one corner.
How accurate is that marker?View Imagerker? The date on it was 1990.
Joe H
Thats a BLM survey point or "corner" in layman's terms. It's cross referenced by the numbers on the cap, which will give the lat & long, and the coordinates, and possibly th elevation.
Many states have been requiring surveyors to place caps with references on the caps for easy information retrival.
Thanks tom and piffen. I've got to leave for work right now but I'll post back later whatever I find from the townhall
thanks for the picture
It's good to know what a pin looks like
Dang I like working where all legal survey plans are registered at provincal land titles, are available for on line download, and refer back to the section township range surveys created in the 1800"s. A lot of the pins that were placed back then are still in place, or can be replaced by legal surveyors because of the original survey work.
Not all pins look like that, just the modern ones
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That monument represents the section corner. Town and Range are stamped at the top. (T36S, R13W). The corner would be the SE corner of Section 29 and the NE of Section 32. They way S28 is stamped shows that this corner is a closing corner of some sorts that you'd have to read the Manual of Instructions that was in place when your state was originally surveyed to fully understand. That monument may or may not have GPS coordinates assigned to it. In Michigan there is a remonumentation program that uses GPS to assign coordinates to all section corners and 1/4 corners. Those records are filed in the county courthouse.
How accurate is that marker?
Short answer: Very
Surveyor's answer: Depends. But they get paid to read tables of info on known or potential movement, thermal expansion changes, what have you, for such things. In days of old, you put a strain gauge on your plow steel tape, and measured the pull to the 1/10 or 1/100 of a pound (or the dude with the field book recorded a measurement). This, and the temperature, to get the differential between the "gauged" temperature--all to cipher up that very important last 0.001 or 0.0001 feet that gets multiplied in every stretch of the chain (which is actually steel tape).Occupational hazard of my occupation not being around (sorry Bubba)
"Ok, so wrap al lthis triva up, windbag. The one-man survey units use a laser and a gps-reading RF sending unit so that the laser theodilite can track the reflector-carrying person. Since the instrument "knows" about where the dude toting the target is to a yard, yard and a half, it need not make any wide "scan" swings to search for the reflector. Smaller movements mean less motion on top of th tripod, which mean better accuracy. But, the accuracy is coming from the strength of the laser signal the insturment is tracking, not the precision of the "here I am" GPS information--which will display to some scary precise decimal places. "
Did you make that up? Cuz that's not how it works. Not even close really....
Capn
I know everything is bigger in Texas, but in Illinois 3 meters is closer to 10 feet than 20.
Bill
but in Illinois 3 meters is closer to 10 feet than 20
Strooth, even late at night <g>
However, the precision of 3m, is plus or minus 3m, or 6m total, which will be a bit more than 18" more than 6 yards, and we could round 19'-6+" up to 20' with a certain amount of accuracy.Occupational hazard of my occupation not being around (sorry Bubba)
i'm surprised to hear that gps is being used for surveying.
at least beyond using it for general use of finding reference points.
i think a good analogy would be taking a 4' level and resting it on top of a straight 20' 2x4 as a straightedge. you can move that 2x4 a lot more than you think without the bubble leaving the area between the lines that one would call "level".
my gps is pretty accurate, but i would say it takes me moving about 5'-6' before the coordinates shift.
would you pay a surveyor to get it within 5'-6' ?
just talking out of my butt here. i expect surveying accuracy to the fraction of an inch.
carpenter in transition
"i think a good analogy would be taking a 4' level......"
Now that analogy is within my level of thinking and I can relate. Gives a better perspective looking at it that way. thanks"would you pay a surveyor to get it within 5'-6' ?"fat chance
I can do that myself for free lol
bad enough I need to plant 3' off the line for future growth of the trees I want to plant.
Another of the great myths bites the dust, Misfit.
GPS works by triangulating your location with satellites in geosynchronous(sp?) orbits. The more satellites you can "see", the better (more accurately) it can give you your location. The downside is that it takes much longer to triangulate with five satellites than it does with three.
Although a lot of people are all hot and sweaty about GPS, few realize that it's accuracy is - at best - + a few feet. That's plenty accurate if you're looking for an address, but not nearly good enough for survey work.
Even the military systems have inherent inaccuracies, but who really cares if you drop a nuke a few inches off of the bullseye. - lol
"Another of the great myths bites the dust"after reading what capn posted you got that right.
guess this gal wasn't feeding me BS after allthanks
Misfit, can you give some more details about the survey you are using. I am not familiar with what you call an A2, but I think some of us can give you some better ideas if you give us some more background.
For example, is the property part of a formal plat? If so, there are ways to measure from the monuments in the street to approximate the location of the property corners. Once you have a good location, you can then use the metal detector to locate the corners more effectively.
Are there any new developments nearby? Of have you seen and survey markings? If so, go check out these points and look for the rebar and caps. Write down the name of the surveyor and give him a call if all else fails. Since he has local control, meaning local points that he used to survey another property, it shouldn't be as expensive for him to locate you property corners.
Hope that helps
Edited 8/9/2007 2:59 am by Engineerguy
The 'A2 survey' is the title on top of the paper I received when I bought the place. Maybe a local term? Subdivided about 20 years ago from an old farm. Other than the dimensions like the example I gave and the name of the surveyor who's no longer in biz, that's all I can tell you right now. I'll pay a visit to my townhall today and see if they can give me anything more specific including a map.No markings were found anywhere other than the concrete marker at the street. This is listed on my survey as the beginning-ending point of the property. We took a measurement from this marker and used the metal detector to hunt for the iron pipe that is supposed to be there but nothing was found. Another reference point elsewhere was a wooden stake with a ribbon attached. Key word being -was- I know exactly where that used to be since that is what I used as a guide when I mowed. But it's been gone for a few years and I wouldn't be surprised if the neighbor tossed it. No iron pipe there either. Now as far as the expense for this survey the surveyor I called is local and is familiar with the property and the original surveyor. She said she charges by the hour and typically it would cost about $1000. I only need to know 2 points about 500' apart so I can plant some trees to define that property line. But she made it sound like it was a complex task and IMO I got the impression that she was sticking it to me. I don't have much choice I guess. The important thing is I need to be sure where I plant the trees so I can avoid any legal problems with a neighbor. I'm fairly certain he will say something when these trees are planted next month. But just like he had the right to remove the fence that marked this 500' line -it was on his property- I have the right to plant the 170 trees on mine. Something tells me he isn't going to be happy about it and will try and dispute the boundary line. Thanks
thats about all I can tell you based on what I know at least for the time being. Maybe I'll get more from the townhall today.
> ... I got the impression that she was sticking it to me. Sounds like it. Here, that sort of survey would be around $300, with an extra $60 or so if you wanted new markers put down. At least, that was the situation when I refinanced my house three years ago.George Patterson
Care to send your surveyor my way? ;)What kind of distant was covered and what was the acreage?I spoke with mine again today and she said the $1000 was a max number. Most likely less. It really depends on the hours they spend doing it. Hopefully she won't send the milkman lolI didn't bother to shop around pricing. The one I contacted is local and is familiar with my area. She's even looked at the maps at the townhall already and I haven't even contracted the job to her yet. I wasn't prepared to have to drop another grand on this project but considering what I'm doing and the money involved it's money well spent at this point.
I did get a copy of the map from townhall and the coordinates match exactly what I have in text. It also shows the perc test locations as well as elevation changes, wetlands and some other incidental info. Other than that it didn't help ME determine anything. Best thing at this point to let a pro handle it. She'll probably do it next week sometime and I'll be curious to see where the corners really are. I might even ask if I can dig before they set the pins to see if the iron pipes are there. Then again if time is money to these folks I don't want to slow them down by being a PITA. Probably should just let it go. Speaking of pins I should have asked her if pins were going to be set or would they just drive in a pipe or ?
Thanks for the additional info Misfit. There are some tricks to locating corners, and I haven't surveyed in nearly twenty years, but you don't forget the good ones.
If your neighbor is a cretin, I would recommend that you go down to a junkyard and get yourself an axle to use as a corner pin. It will take some work to get it set, but your neighbor will never be able to pull it out. And it would definitely show up with a metal detector. Trust me on this one. We used them to set high tide property lines along the beaches.
You should also have her shoot in a mid point boundary points. That way you neighbor can't misconstrue the property line. Unless of course he wants to bring in his own and pay for it.
"If guns kill people, a spoon made Rosie O'Donnel fat!"
a couple axles and midway boundary marker
got it and thanks for the tip
You get out there and help'em and show some interest, and I guarantee you the price will come down.
After she sets the points that you require, have her set some "ties," or reference points so in case the points are lost, they can be re-set by "two taping." This is nothing more than two or more points, like nails in trees, or "X's" cut on concrete walls, or nails in asphalt driveways, that have distances from the corner recorded. To replace a corner, just pull over the distances and strike arcs and put the pin at the intersection. Have her include these on the sketch she provides. Corners near the ROW and PUE's are the ones most often lost.
If you want a more permanent point you can pour a concrete monument flush with the ground with a galvanized bolt in it. The neighbor would have a hard time destroying that one....
You get out there and help'em and show some interest, and I guarantee you the price will come down.
Now that's funny, right there.
"Labor Rate $30 an hour.
If you watch $50.
If you help $70
If you already tried to do the job yourself $100 per hour."
Seriously - we try to discourage the owner from "helping" unless we KNOW they have prior survey experience. I have a few clients that have been great help, and they get a discount. Most just want to chatter and get in your way. We make it a policy to schedule a "walkaround" with everyone AFTER the job is done, to show them what we did and usually how it was done.
But please don't try to help - it probably won't save you any money.
Different strokes.
What I ment by "help" is if the client had located corners or had relevant documents that would save time in research or field activity. I didn't mean cutting line, setting points, or getting underfoot.
We usually left that to the kids and dogs....and the occasional PO'd bull....
My last survey, guy told me my help saved his crew better than a full day. No surprise on this mountain where one corner is a 54" d. tulip poplar.
Major savings to me, as expected.PAHS Designer/Builder- Bury it!
nah yours is even funnier especially the DIY part
rotflmboI'll just let them know that I'm available if needed. no problem here with being the grunt if they need one
"You get out there and help'em and show some interest, and I guarantee you the price will come down."heck I'll wine & dine them too for that matter lolseriously I'd be more than willing to do that just for the learning experience. I was more concerned about being a PITA and planned to just keep my distance out of the way and be available if they needed anything
"have her set some "ties"I did that with my septic tank cleanout and now I can find it easily.
Are you saying I should ask her to set these points or should I do it afterwards?
Ties for corners or monuments really need to be more accurate than for a clean-out. Usually lay-people don't know how to use a chain or tape graduated in .01 of a foot. If the surveyor does it, the ties can be included in the official sketch and field notes, and would then be recorded as a public record along with the rest.
We would ususlly occupy the point and turn angles and observe distances to at least two ties. This way if the line was obscured or points were lost, we would have a backsight and/or starting point to look for other corners. Just explain your situation that you are afraid that the points may be disputed and removed by the adjoiner.
If you want to do it yourself, let me know and I'll give you a few tips.
I'll run it by her and see what she says.
thanks for the offer. I'll be sure to contact you if I need those tips.
I don't think the sticking it to me is acurate.Here, a surveyor will not do one line only. They have to esatablish al the meets and bounds to be accurate because of the way deeds and descriptions are written.
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"Here, a surveyor will not do one line only"same here. but she said she's probably going to skip 2 of the points because of heavy overgrowth. irregular property lines here as well
Mac may have already covered it better than I can, but here is my two cents worth...
I took a class to introduce myself to GPS 5-6 years ago. Some things may have changed since then and there are differences in different parts of the country because accuracy depends on how many satellites your unit can see at any one time. There are more visible closer to the equator and in flat country than there are up north in mountainous country.
Military precision was not available when I took the class. i don't know if it is now or not.
but I had survey done on my place last year and they employed some GPS along with traditional means.
one of the principles is that the longer a GPS unit remains in the same location, the more readings and calculations it can make, so the more accurate it becomes.
My surveyor has a permanent large GPS unit mounted someplace near the county seat at a well established set of co-ordinates. It always stays right there. Then the portable units reference back to it for their accuracy. Then all that had to be connected to what is actually found on the ground re old corner markings, and everything reconciled with the deed description.
Precedence does have some value in these matters so having your survey done and recorded before the neighbors do can have some value in the future.
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Taunton University of Knowledge FHB Campus at Breaktime.
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"Precedence does have some value in these matters so having your survey done and recorded before the neighbors do can have some value in the future."why is that? I'm sure the neighbor has a survey just like mine only with different statsOne thing I was sure to ask the surveyor was is the final result guaranteed? The reason being somewhere maybe here? I read that it's possible for 2 different surveys to result in different corner points. She told me that typically only occurs when you have 2 adjoining parcels out in the middle of nowhere. In my case since the survey is fairly recent -20 years is recent??- and the 3 parcels involved were all done at the same time there is no reason for any discrepancy. In addition all 3 have their own permanent concrete markers as the starting point. I've seen all 3 so I know where they are.
In your case, there is probably far less room for error, but something like mine is out in the boonies, almost nine acres with irregular boundaries and one marker from a hundred years ago long lost when a road was widened. my northern boundary was defined by a line from point A to point B with no angle recorded and point B doesn't exist any longer so....I am meeting next week with my neighbor to the north to negotiate resolution...
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> My surveyor has a permanent large GPS unit mounted someplace near
> the county seat at a well established set of co-ordinates. It always
> stays right there. Then the portable units reference back to it for
> their accuracy.That's called "differential GPS". The permanent unit "knows" where it is. It can then subtract that location from the one provided by the satellites, producing a "difference". Transmit that difference to the portable units. The portable units then subtract the difference from the position the satellites are giving them, which produces very accurate location info.George Patterson
Schondstadt makes two models of field metal detectors, with adjustable sensitivity. There may be a good chance that a few of your corners were destroyed by phone line or other easment work, but usually not all of them. They exist, but it takes a little practice to be able to deferentiate between signal types.
GPS is only good for gross topographic surveys. Control points ususally have a reciever placed over them for a 24 hour pass period to get milimeter accuracy.
More passes=more accuracy.
"but it takes a little practice to be able to deferentiate between signal types."That is an understatement if one ever exists! LOL I actually expected to just walk up to the area turn on the unit and have at it. Boy was I was mistaken. Definitely takes a trained ear for this type of work.I wouldn't be surprised if what you say is true. If you eyeball the site line for the neighbors underground phone service it appears the trench from the box at the street could be right on the property line or darn close to it for sure. We searched for 3 other listed iron pipes and couldn't pick up anything there either. There was one possibility based on the sound but the location was a good 50' off from where it should have been. I was going to dig there and look but decided not to since it was clearly on the neighbors property. The only 2 certainties we found were the magnets on the phone service and the rebar in the concrete markers.
Wow, you've been fed a lot of, shall we say, off-base information. Not all of it is wrong, but I'm confused, and my company does survey work. So...since my partner, who is the licensed surveyor, doesn't read BT, let's see if I can either help or muddy the waters a bit more.
First. The survey-grade metal detectors are very good at finding ferrous metal. That is to say, iron and steel. Copper, brass and aluminum cannot be detected. Most survey pins are either a pipe, a pin or rebar, a concrete or stone marker (some concrete ones have embedded reinforcement) and sometimes we find some really odd ones such as old axles and gun barrels (really!). If you were using a "hobbyist" metal detector, the ones with the big disc on the business end, you might be out of luck. Then again - there might be nothing there, as is the case with many of the jobs we do.
Second. GPS is not all it's cracked up to be. We use GPS frequently in our work and it is most often used on large surveys where we might have a hard time running a conventional survey traverse to a point way out in the woods and need to tie in to a fence line, stone wall corner or monument of some kind. It is rarely, if ever, used to do 100% of the survey field work unless ALL of the expected monuments are present and we are reasonably certain that they are the CORRECT monuments. SO, your surveyor that you spoke to about running that line, is not feeding you any BS. It can't be done with GPS if there's nothing to base it on. We also cannot set survey monuments with our GPS units - there are some survey-grade GPS equipment out there that costs tens of thousands of dollars with which it's possible to do so.
As for accuracy. We have run many checks of our equipment, comparing a properly-calibrated $25,000 Topcon robotic electronic total station (conventional survey instrument) to our cheap-but-accurate Thales/Ashtech GPS. They check, without fail, to within 0.02' every time. Usually dead nuts. So the GPS is highly accurate. In running post-processing of our GPS data, we get error readings of less than 0.01', or a couple of millimeters. Even so, GPS is only PART of a complete survey solution. Anyone who tells you otherwise either has no idea, or has invested tens of thousands of $$$ in state-of-the-art equipment and can, indeed, do it all with GPS.
But in spite of it all, you still need a starting point, deed research and a licensed surveyor to set your corners. That's where the expense comes in. Our policy for off-the-cuff estimates of boundary work is to start at $1 per foot of the perimeter and work up or down from there depending on how much information and field evidence is present. So for a square acre, roughly 208 x 208 feet - we would estimate your survey costs at about $840. The bigger the parcel, the more "pre-research" we will do before giving a cost estimate.
FYI. Hope this helps a bit.
Edited 8/9/2007 9:48 am ET by JonE
You should teach. Very clear and concise explaination. Surveyed for 30 years and I learned something.
I'm amazed at the accuracy of the RTK/RTSS units out there now that will "talk" to the TS, and the prices are resonable. About 25K. Beats the old crap we had.
I'm impressed with the units on the maintainers that automatically raise and lower the blade, to brush the tops of the bluetops...
and the prices are reasonable
And, in some ways, cheaper than a good rod or instrument man--and a lot less work than training up a greener-than-grass newbie (who will not have to have 'bad' habits unlearnt from him).
One of our locals runs a two-hand shop; the office person who answers the phone and handles the billing, and the LS. He was an 'early adopter' back when the "buy back" was about 2.5-3 years of a "good" hand or 3-4 new-hires. He's busy until the entropy of the Sun, too.Occupational hazard of my occupation not being around (sorry Bubba)
training up a greener-than-grass newbie
Had a power line survey done last summer.
The old guy had a newbie grunt, climber of cliffs with him.
He had just started and was thinking this sucks.
He was telling me working in a mall selling phones or something was sounding better & possibility of meeting women too.
I told him he was better off learning something useful & what kind of girl hanging around the mall did he want to support for the rest of his life?
It was hotter than hell & he had some good slope to cover, but still, working in a mall?
Joe H
It is amazing to me just how accurate most of the old time surveys were. I worked briefly on a survey crew in 1960. The standard crew was a "chief surveyor" who ran the transit and bossed the other guys around, the chainman (the guy who stretched out and held the steel tape) and the rodman, who held up the measuring stick. As mentioned before, you stretched out a tape measure (or "chain" as they are called - I guess in the really old days they really did use a chain) and held it to a specific tension at a height on the rod that would keep the tape level. You then marked the spot with a plumb bob and then everything would move with the transit plumb bob being moved over that previous spot. On steep ground, the setups could be a very short intervals and would sometimes have to be moved over to get around obstacles. As mentioned before, the length of the chain (tape) had to be corrected for ambient temperature. I think the accuracy of these surveys was surprisingly good given the way they had to be obtained. Running up and down the hills was a pretty good workout. I later went to work running a hundred pound jackhammer doing high scaling and found that it was actually less work, although it paid more.
Hey, I started surveying in '67. No damn electronics then. Just a K & E transit, 100' chain, plumb bobs, hand level, 12 lb sledge, machete, and a mean-azz Party Chief.
He wore startched khakis, small brim Stetson, polished Wellingtons, and I never saw him break a sweat even in the hottest weather. Only saw him roll up his sleeves a couple of times. Had a pair of startched gloves too...
LOL, when my surveyor's helper came out on a saturday to set the final pins for me, while the boss was sick with the flu, the helper's girlfriend came along with hie for an outing in the woods and to help him carry stakes, flags, pins and hammer!She was a keeper, I'd say!
edit - yeah, it was about 5°F that day
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Edited 8/9/2007 8:26 pm ET by Piffin
I've done numerous boundary surveys by my lonesome. Three tripods, two prisms, a good TS, and one machete. Set up the base line, FS & BS, double angles, feet & meters, turn to the pins, same drill as in setting the prisms on tripods over the points, and punching it into the DR, and recording it into the FB.
I still think the mininum for an effecient field party is three, especially if you're setting points. You can do lot surveys with just a tape and no gun if the points are there.
Standards have slipped considerably, as you can't even "bump" a point over to agree with a previous survey...
Standards have slipped considerably, as you can't even "bump" a point over to agree with a previous survey
Yeah, well, we could waste a near-inifinite number of electrons and photons sorting thtough all the various ways standards have slipped <sigh>.
My personal new fave is where they get all enamored of the numerical model they've built up even before leaving the office. Sure, "pre setting' the points goes a little faster out in the field--but, if you transpose just the one, it's GIGO.
I had the partially-dubious pleasure of being taught by the legendary Dr Turpin, who, after five decades licensed, had finally allowed as how those theodiolites might actually be a useful part of the business. He was very good at his trade--almost too good to teach it in some ways. But, he had a belt-and-suspenders approach about coping with the three classic errors. Which is something I know I carry around with me, too--always watching for those "blunders."
Oh well, that's life. We did finally convince our engineers in Edniburg that no mater what the numerical model their survey crew came up with, the existing road really was 3.1 to 3.7' lower than their model, and no, TAS won't let you just "sorta make a ramp of it, maybe?" not at all.Occupational hazard of my occupation not being around (sorry Bubba)
"Blunders, systematic errors, and mistakes." All commonly known as FU's.
Prism error is a hard one to spot unless you check everything at least once a week.
Used to do that with a chain before the EDM's and TS's. Had a "good" chain, and a "work" chain. The "good" chain was right on the temp conversion scale. The "work" chain could be off .02 in really hot or really cold weather. Same K&E chain, just different densities of metal...
Same K&E chain, just different densities of metal
Yeah, well, just one more way to keep the surveyors poor, having to have good-better-best chains and the like <g>.
Dr Turpin spent an entire week on the metalurgy of chains, and why everything was required to be suspect until proven otherwise. Just life, only measured to tiny increments <g>.Occupational hazard of my occupation not being around (sorry Bubba)
Just to help clear up some GPS fog. I sell and service highly accurate(RTK) gps sytems. They are used for agriculture, so I don't know all the specifics of surveying.The Capn and others are correct about cheap recievers and their accuracy. There are several other levels of accuracy available for a price.The coast gaurd has an a.m. radio network setup along all navigable waterways, that provides 1 meter accuracy for free, as long as you are within range. We easily receive those signals where I am from Paducah, KY Louisville KY, and from St Louis.There are several companies that offer a satellite based correction varying from 10 cm accuracy back up to 1 meter. These are fine for farming, but not even relavant for something like surveying.Highly accurate GPS is based on RTK, a system where one receiver sits still, and through the use of both civillian and mitlitary channels assumes a position that is highly accurate, and communicates to the mobile gps units through a radio modem. The RTK systems we use have an accuracy of -1", that is also relvant to elevation between the two units, but not necesarrily to sea level.The military is not actively scrambling the civilian channel any more. They have their own channel which is encrypted, and unusable, except for the presence of it and a time stamp it provides which is unecrypted, that makes the RTK sytems functional. The reason for the inaccuracy of uncorrected gps is the shifting of the radio waves as they come through the ionosphere, that causes some communications to take longer than others which is why the local base, or some other base knowing the time and absolute location is necesary for good accuracy.I just had a survey done, and they wallered around with there gps and lasers all day , then finally went in the woods, and found the old hedge cornerposts and measured form there, saying that the field marks take precedence over anythng they could measure up anyway.A medium to large guy named Alan, not an ambiguous female....
NOT that there is anything wrong with that.
likewise for the RTK mention
found some good read for it as well
""work" chain could be off .02 in really hot or really cold weather"talk about splitting hairs! yet over a long distance I can imagine the error. like I already said once this is something I'm glad to be letting a pro do. in my mind it seems simple enough to just shoot some lines and intersections but without considering a number of variables you could be miles off--literally!
I remember a story about a county that had an old chain. It was worn and extra long.But it had been used for one section of land. Whenever there was a guestion about the surveys in that area they had to haul out the old chain..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
With a chain, experienced rodmen, flat terrain, and moderate air temperatures, you will never get closer to duplicating a distance more than 100' than .01.
With modern EDM's that are properly adjusted, you can stretch that to a quarter mile.
We have to work error theory and adjustments into virtually every boundary and control survey I ever did. They had the same math 300 years ago and used it, but you can't duplicate their observations.
That's why surveys have a "senior and junior" designation. The very first observations were always "right."
Maddening....
question for you:ever have any hostile landowners prevent you from crossing their property while surveying? while I don't anticipate any hassles from said neighbor I have no intention of notifying him of my plans. my surveyor told me that they have the legal right to enter any property for surveying after notifying the property owner. she once had to call the state police to babysit some zipperhead who was threatening to shoot trespassers. signed the contract for the survey with her yesterday and the trees are scheduled to be planted first week in Sep. it might get real interesting around here during the next few weeks. I did check with the townhall for any required permits for the tree plantings and nothing exists. I am free to do what I want where ever I want on my property. the only suggestion they did make is that I plant 3' off the property line.
Yes, myself and crew have had guns pulled on us, with a few instances of shots fired, dogs set on us resuling in two maulings, and a few dead dogs from machete cuts and line rod impalings. Don't care what the law is, the man with the gun is "right."
We always notified any and all landowners by registered mail, return reciept, that we MAY have to enter their property to complete a survey. This missive included date and contact information for our office personel. On the day proceeding the survey, adjoiners would recieve a phone call, and/or a door hanger notifying them that we would be there the next day.
In the State of Texas, you must recieve permission from the landowner to enter his property, or face trespass prosecution. Don't know about other states, as Texas is different in all of it's real property rules and regs. In Texas the landowner has precedcent, except in PUE's and construction easements.
With present day technology, you can stay in the bounds of the subject tract and not need to enter adjoiners except to excavate a corner.
jeezus! I guess it can get ugly. I asked because if she located and marked a corner but the neighbor comes out and says "wrong-that's not the property line it's over here so get off my property" can he force her off? she says no that in CT the surveyors have the legal right to enter an adjacent property while surveying if needed. I just don't know what to expect from this clown. I sure hope it stays civil but then again she didn't seem to concerned about it.
I'd have a cell phone and a camcorder and record each days progess by filming the points set at the end of the day.
Have the sherriffs number on speed dial, and maybe have a cruiser come by a few times.
good idea thanks. cell phone I have but no camcorder. I'll ask an inlaw I think he has one.
Edited 8/16/2007 7:21 am ET by misfit
You don't have that right here in New Jersey. In fact, if the land is posted with no trespassing signs, you can be charged and fined. Why would you want to be surveying someone's property when the owner didn't ask you to do it?Here, when the township re-appraises for taxes, they only check the embedded markers for the frontage, and they stay off your land while they're doing that. If my neighbor wants his land surveyed, there's no reason for the surveyor to get on my property to do it.George Patterson
see my post to tom. I wouldn't be paying to survey someone elses property just mine. sorry for the confusion.or another example would be when shooting the corners that are 500' apart and that 500' line seperates 2 properties wouldn't the tripod be sitting on both properties to sight the line?
I can do a complete survey by not occupying any points on a disputed line, other than to set a prism on it.
He is not surveying somebody elses property. He asked about surveyor going onto the neighbor's property is all. Sometimes that is necessary to locate markers, though like Tom said, modern equipment eliminates most of that. For a simple city lot, it should be un-necessary, but I can think of a couple example here, where the primary line of indicators are granite markers located on what is called in most surveys, the center line of the island. Taking measure from one of those monuments when lots are broken down smaller over the years from original homesteads and farms into more building lots, a surveyor may have to cross 3-4 lots to get back to original takeoff point. The more I think about this, the more sites I recall finding just that. As a builder, I am comfortable doing a layout when I am one a lot with the origianal marker to measure from, but once it gets a second lot removed from that, I have them hire a surveyor.The most common reason for surveying here with the coast is to establish flood zone elevations and a 75' setback from NGVD, an objective reference for average high tide level. Everyone wants to place their house as close as possible to the water for views etc. which means proving where the setback line is - not easy on a rocky coast.
So getting from that reference marker to the lot in question means playing leapfrog.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
As Piffin said things aren't always that simple and neat.I have two irregularly shapped lots. One corner, that is common to them has a driven pipe that is "commonly assumed" to be accurate.When the house across the street and 3 doors down was surveyed they used that pipe as one of the starting points. Don't know what else was used.When I built in 79 I had it surveyed. My survey only shows the corners and inflection points. On one outside corner a mark was chisled on a retaining wall. That has since weathered away. On that same side one was chisled in stone that was a corner in a raised planter bed. That is long gone.On the otherside a nail was placed in the middle of the neighbors driveway (house existing since the middle 30's). Since then the asphalt driveway was replaced with a concrete on. Thus the nail is long gone.About 3 ft off the boundry line to the road and aobut 7-13 foot from that corner there are several pipes that have no purpose other than to be markers, but they are two far off to make any sense.The other corner on that side, was the best that I can remember, was a nail placed near where a fence was later installed and might be gone.The internal points of inflection in the boundry line was only marked with stakes and they where long gone after grading.My survey only shows the points and does not reference anything else.When a new person bought the house that had the corner in the driveway they had it surveyed and I got a copy of it.That one shows the lots 3 and 4 lots away to find the points.One of the reference points that they used was a post to mark the access pathways for 2nd tier houses. I know of that is installed between the wrong lots. So I don't have any faith in location of those posts.Of 2 nonimally parallel lines the assume that one was accurate and used that as a reference. But they only have 2 points that are 50 ft apart. But on the parallel line they have 2 points that 125 ft apart.Also they claim that one side of one of the lots is 25 ft, but the plat and my survey shows it as 30 ft. But still way over in their driveway..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Surveys and land descriptions are usually based on a POB (point of beginning). Usually this point is a section corner or quarter section corner, or in the case of a subdivision it would be the subdivision corner. In order to complete the survey .. the surveyor will have to tie into the POB and another point on line (usually the next section/quarter corner or another subdivision corner). In most cases this would not be on the land of the person obtaining the survey. New Jersey does in fact have a right of entry law pertaining to licensed land surveyors as well (N.J.S.A. 45:8-44.1 and 45:8-44.2).
Maddening
Too true.
Minor rant: Can it be that there are no drafters that can be hired by a LS that are externally aware? I'm so tired of reversed bearings, it's beyond description. Maybe that's why I'm seeing so few drawings with a declared POB (good thing I know how to read text descriptions <irony>).
And, what's with transits not closing? I wrote a spiffy little Autolisp routine to draw lines from bearing & distance calls. The routine runs at ACAD's native 6-place accuracy (since I was too lazy to make it either lesser or greater). Yet, it's been months since I've seen a wet-stamped file that will close closer than 5-6 feet. Ok, some of that is cleaning up reversed bearings, but still . . .
Ok, and I'm neck-deep in a horrible survey for a bank out the other side of Midland, too (their own drawing does not match the metes & bounds)--so, I'm cranky from having to do their work, too <sigh>.
Oops, guess that was a major rant, wasn't it?Occupational hazard of my occupation not being around (sorry Bubba)
My ACAD 2000 does it fine if you set up your drawing parameters first. Maybe the RPLS isin't doing his balancing and calculations correctly before he gives it to you?
We always had to close at least 1/10,000 before we turned a traverse in, after we got EDM's. With chain it was 1/5000. I always looked at angles first. Have'em double the angles, record both, and enter the mean, and read feet AND meters. Constructed points, corners etc., should always be occupied and the angles turned and distances recorded in the same method.
Our methodology was to construct a traverse including as many of the found points as possible, balance that traverse and calculate the cutoff's and/or missing corners to be set, set those, then run another traverse to include those, or just a portion it it was a missing pin, or a construction or other easement. Have copies of the FB when you are plotting.
The field-book is your friend, even if it is yellow....
My ACAD 2000 does it fine if you set up your drawing parameters first. Maybe the RPLS isin't doing his balancing and calculations correctly before he gives it to you?
Yeah, if you don't lie to the s/w it won't lie to others <G>.
Scary that the last drawn correctly (that was WYSIWYG, too) was the survey for my house (1999) which was DXF-ed out of the numeric model and into R12 (yes, 12) format.
I have one on my desk right now where the 'final' drawing is four XREFed files, two of which are contradicting XREFs of their own (can y' feel the love here?).
No, the bank is disaster, lines drawn, but dimensioned as arcs (and incorrectly, R1645.0' is not R1600'), bearings reversed, no POB--oh, but, they did model the topo contours, in Z*3 so they'd stand aout, then drew intersecting lines willy-nilly between all the resulting elevations <sigh> Even better, I'm pretty sure one whol batch of the contours are wrong (positive Z values labeled as negative).
Yeah, I know, I just need to fork over for Super-Z and Flatten-It, just stubborn and poor, and cranky <g>.Occupational hazard of my occupation not being around (sorry Bubba)
The earliest ACAD that I used was R-13. R-13 and and R-12 will not interface with later versions of AutoCad.
I never use arcs to construct traverses, only chords, with bearings (or angles) and distances. I'll use the arc only for sq. footage and/or to indicate grade areas.
I don't know how to adddress your vertical problems, as I let the RPLS work with that unrewarding shid. Countours can get messy if you don't integrate the points.
Educate me about Super-Z and Flatten-it as I am sadly ignernt....
Educate me about Super-Z and Flatten-it as I am sadly ignernt....
Ah, the increasing use of Civil Desktop & Land Desktop (which both generate nifty ACAD Objects only usable with the exact same DT version&release) has spawned a coresponding need, the need for 2d representations of what the objects construct in 3D.
Flatten-It (allegedly) has a tiny peice of the OEM Desktop, so it can take a 3d shape and "remap" it as a 2d polyline. Doing so using a single Elevation/Thickness, too--so the 20' "throat" depth in plan does not dimension the 1023' between the 0 elevation of the new drive line, and the contour mapped at -995' "below"...
Super-Z is a tool to take objects at different Z elevations, and drag all of their endpoints back to one Z plane.
Just few things in life as fun as "objects selected do not intersect" (especially when it's true, as the other line is in a different Z plane and UCS orientation--no matter how it looks in plan view).
Side Note: I've seen the worst possible brand name for tortilla products--Milagro. Maybe it's me, but "if you get a good [tortilla product] it's a Milagro" seems to tempt fate a tad too much <G>. (Milagro is spanish for 'miracle')Occupational hazard of my occupation not being around (sorry Bubba)
I hear you. Propriatry software improvements in ACAD are linked, and may not operate in all versions.
Can't remember the terrain modeling software we used back in '98, but it may have been a Topcon product. Worked well with Windows 3.1. and coupled well with out Topcon DR's.
The closure problems you're having is bugging me too. Sounds like a "standards and practices" issue. Don't know if your organization is running the crews, or if you are using local independents.
IMHO, anytime a traverse is brought in from the field, it must close within accepted accuracies. The PC should do this before leaving the site so errors and blunders may be located and corrected. I don't think these new PC's are being taught how important "strength of figure' is, and how to balance shots. It's hard to get a good closure if you don't follow the methodology.
I can give you a rundown if need be, but otherwise, I would demand that any traverse close before accepting the data to plot.
The closure problems you're having is bugging me too. Sounds like a "standards and practices" issue. Don't know if your organization is running the crews, or if you are using local independents.
I'm getting the info from the offices of RPLS & CE firms (about half of which seem to harbor satellite RPLS operations). Somewhere between the field work and the drawing production, a great huge gap of rectitude seems to be occuring.
So, that ROW road radius gets "eyeballed" even though it defines a property line. My principals here assume the drawing is accurate, and proceed with site work, only to find I can't make graphics and data match <sigh> (rounding 1645' to 1600' is so not good). My other fave is non-tangental end points, which, to my understanding, ought not be possible at all . . . Occupational hazard of my occupation not being around (sorry Bubba)
Geez Cap'n, you sure hard on the boys. ;-)
You never laid out a traffic island with 200' of garden hose when the curve data didn't fit?
See, that's a field problem. You go in and find the PC & PT, check the 1/2 Delta, shoot the chord and it's fine...until you check tangency on both ends....and it doesn't work. Time to research, or set on traverse through the PC & PT and develop new curve data to match the points on the ground. 'Course that may cause problems it it's supposed to be concentric with the center line and the opposite ROW.
In curves, the chord is usually the defining portion of the figure. You may always change the Delta if need be, and the tangents and calc a new radius.
Your "principles" obviously have more engineering experience than surveying know-how. I don't know how many times I've had to tell engineers that this or that won't work as the data doesn't fit. That's where any organization needs a RPLS to run interference between the crews and the engineering staff.
"Make it fit" doesn't work when you're talking about $20,000.00 a sq ft....
You never laid out a traffic island with 200' of garden hose when the curve data didn't fit?
Shoot, I've laid out B-splined (idiot archy's) curb radii with nothing more than a nylon 100' tape and a cheapo phillips screwdriver with the paving excavators waiting on me <g>
(Why is it that you never have your "beater" shoes on when it's windy and you have to spray a case of paint for a parking lot layout . . . ?<sigh>).Occupational hazard of my occupation not being around (sorry Bubba)
Ahhh, marking paint. One of those "modern" inventions that is as abused as alcohol.
Still can't beat the "whiskers" on blue tops for laying out parking lot islands in much processed rock hard second course base....
on blue tops for laying out parking lot islands in much processed rock hard second course base
And, those few times you really do have enough sledge, that's when the lime wants to puff up and settle into a person's sweat and then engage happily in reactions that it has steadfastly refused to test "to" in the nearby base & subgrade . . . Occupational hazard of my occupation not being around (sorry Bubba)
oh-boy here we go! I think things are going to get real interesting around here. maybe even outright ugly. the neighbor hasn't been around for a few days and I don't know if he knows anything about the survey. the surveyor started today and set about 6 or 7 pins. I wish I was around but I wasn't. each pin has a cap with ID marks and a ribbon tied to it. there's also a 2' stake with ribbon next to each pin. here's the deal- one of the new pins is located about 10' from where I was told the corner was when I purchased. it's in my favor so not a big deal other than that newly located pin is now only 2" from his blacktop drive. it makes me wonder if I should be concerned about setback requirements? this is a rural area and I don't know the specifics. additionally the new location also means that 500' line where I need the corners located will also move in my favor. the 10' error also means I've gained quite a bit of property and I'll bet that loss to my neighbor will make him ecstatic-not. I can just visualize what his reaction will be when he sees the new stakes and it's not good. I hate to even think what'll happen when that 500' line is set.the contract with my surveyor states that she'll be finished by next friday and at that time she'll walk the boundaries with me. I might as well just sit back and wait instead of asking her about it now.the one thing I'm still hung up on is how her survey can be considered gospel. no disrespect meant to her or any other lic surveyor but how is that 20 years ago a survey was done and my neighbors driveway is set X'? from the property line. now years later another survey shows the boundary line is 2" from this asphalt. comments suggestions advice? this survey stuff is all new to me and I don't want to ignore something I may regret someday. for the most part I don't care that his drive is 2" away from the line and I don't really see a need to make him move it. but should I be more concerned?
Nothing says her work is gospel. It can become gospel if she records a "Record of Survey" showing the results of her boundary work and, over the years, other surveyors demonstrate acceptance of her work by referring to it on the surveys that they record. OR If her work is challenged in court and she prevails - then it's gospel.
That is one of the reasons you need to go with the most competent surveyor you can find - there's no cost savings if her work is cheap but legally indefensible. Boundary surveys (that's any survey that defines one or more boundary lines - like a building staking that is hoping to be just inside the minimum setback) must be legally defensible - if your neighbor doesn't like it he/she may sue!
A little background & some responses to other comments made above follow:
A boundary survey is comprised of - title research (get the documents that conveyed the land - often back to when the land was first transferred from the U.S.A. to a private entity *and adjoiners* - recovery of evidence: search for corners, and in some cases lines of occupation, and measure their location *this is where you use GPS/Theodolites/total stations/chains/whatever*, - evaluation of evidence (of the corners that were found - what's original, are the measure positions in harmony with conveyance documents, etc.),application of boundary law (what is called for in the deed, what evidence controls, etc.), - if corners are missing, you must now determine the location of the missing corner based on the evidence and... if you have sufficient evidence to support your finding, you can set the corner
Some terminology:Subdivide: to divide into two or more parcelsParent Parcel: the parcel being subdivided
Some basic rules:1) You can't subdivide land that doesn't belong to you. This means that if a prior survey didn't properly establish the parent parcel - corners/pins may not properly represent the boundary.
2) The ORIGINAL corners set by the subdivider (their surveyor) are the best evidence of the subdividers intent - THEY CONTROL. But remember the subdivider can't subdivide or sell land that doesn't belong to him. So corners on the exterior boundary of a subdivision (that would be the parent parcel boundary) might - or might not - control.
3) There are thousands of possible evidence scenarios - deeds, monuments, and occupation are not always in harmony. When they're not, you've got to determine what controls. This can be very complex. This means you can't determine how to survey a parcel of land on an internet bulletin board and you can't determine a legitimate cost based just on the perimeter of the boundary.
4) You can't survey one boundary without surveying the adjoining boundary AND there are many situations where you can't determine one or two boundaries without surveying the entire parcel. However I'll repeat: you can't determine how to survey a parcel of land on an internet bulletin board - You've got to evaluate the parcel at hand.
Yes! Differential GPS can reliably measure to sub-centimeter accuracy (that's slightly less than 1/2"). But that's just measuring - one small part of a boundary survey.
How much should you pay for this? Who knows!
Good Luck - John
John
thanks for a little more insight on the matter. if I understand what your saying then am I safe to assume that if the recorded survey from the subdivide agrees with what my surveyor finds and the control points on the main road are the same ones used both times the end results are one step closer to being gospel?I'm not sure where your coming from in regards to how to survey on an internet board and I do know anyone can say anything. but that is not my intention with this thread and I hope I didn't imply otherwise. granted I'm lacking when it comes to understanding alot of the terminology but I've already learned plenty from TomT capnmac and JonE to name a few. and after a bit of research what they've said has been true and helped me. at first I tried to save a buck and use a metal detector-yes we used a professional grade unit-to find the iron pipes. no such luck so I hired what I believe is a competent surveyor. my local town hall has also used her services so I hope-for me-that shows her credibility is up to par. based on what has been said and done so far the cost of the survey is no longer of concern to me. I'm am thankful I listened to a few of you guys and hired a surveyor instead of winging it.thanks for speaking up I appreciate it. I see this is your first post even though you've been around for awhile. so let me be the first to say WELCOME
Re what Tom said about working with the neighbor: If, as an example, the survey were to show that the corner of their garage were on your property, and it was like this when you bought the place, it would be wise to "preemptively" offer (if they don't contest the survey) to provide them with some sort of legal document either giving them the property involved, or giving them a 100 year lease for $1, or some such.This right away demonstrates that you're trying to be reasonable, and also gives them some motivation to be reasonable in return.Re the driveway, in most areas a drive isn't subject to setback requirements.You do need to look into your states adverse possession laws (the surveyor would probably know them fairly well). If the lines have been assumed to be a certain way for some number of years (eg, 10) and the non-owning party has built on the property, fenced it in, or maintained it in some way, they may, in effect, "own" it. (Though often asserting that ownership requires a lawsuit.)
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
other than the driveway it doesn't appear that any buildings or structures will be involved. however she isn't done with the survey yet so I'll have to wait until then. but I like the $1 lease part and will keep that in mind.I did wonder about the adverse possession and if it would have any effect on this. I sure hope not. there are a couple places on my property that he's run his brushhog about 10-20' over the property line. I just ignored it and returned the favor by doing the same to him. so essentially these areas haven't been maintained solely by him for the 8 years I've been here. however the area where the new pin is inches from his drive has always been maintained by him.thank you Dan. you gave me the type of suggestions I was looking for. I will look into this adverse possession thing.
Note that for adverse possession, it's not just the time you've owned the place. You could have bought it yesterday and have the clock run out tomorrow.But generally just mowing isn't enough to establish this. If he'd planted flowers or some such that would be getting closer.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
"run out tomorrow" really? that sux if it's the casewait a minute I just realized something. if the new lines are in fact different than what was understood then his fence that he torn down would have been on my property. that would be a good thing-yes? or can he rebuild it and still claim the adverse possession if it comes to that. he tore the fence down months ago.
Those are your typical touchy issues. And why it's far better to arrive at an "understanding" (legally documented) than to fight it out.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
it figures. just when I though I had an upper hand. uh oh--I think the neighbor is home. DW said someone is out walking around looking at the new stakes. time to get dressed and be ready and alert. here we go-
<gulp> lol just kidding I hope?
well it was a false alarm yesterday as for the neighbor returning home. my DW got a little too excited when she saw someone looking at the stakes which caused me to jump as well. whoever it was was only there for about 5 minutes and then left. I've no idea who it was other than I know it wasn't the neighbor. I have to wonder why they were looking at the stakes unless the neighbor was contacted by my surveyor about the survey and then he sent someone to investigate.
I am under the impression that while the concept of adverse posesion is is simple, that the details are very exacting and very from state to state.So any discussion of them is really meaningless.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Yeah, the law varies state to state, and much is precedent vs written law. So it's rarely black and white (except when it's black and white). The type of thing that can cause expensive legal battles.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
I googled my state and found alot of information including a number of statutes. I can understand why you would say any discussion here would be meaningless. I did find mention that 15 years is the magic number for someone to make a claim using it.
Thanks for the welcome Misfit. I think you are headed down the right path. You've hired a surveyor that you believe is competent - she knows the area well enough that town hall hires her - that's a good sign. You have to trust your surveyor and rely on the results of their work. She should be able to explain to you in laymans terms how she determined the boundary. She should be willing to go over her results with your neighbor (provided he's not hostile/violent/unstable).
If your neighbor believes the boundary is in a different location, have them hire another surveyor to check your surveyor's work. There may be a difference - hopefully not. If there is a difference, then the two surveyors should review their evidence and discuss how they came up with the boundaries they did. If they can agree on a boundary, it's likely that it's in the right position.
DanH is giving you good advice when he says "in most areas a drive isn't subject to setback requirements" and "it's far better to arrive at an "understanding" (legally documented) than to fight it out" (ask your surveyor about how to do this in your state) and "the law varies state to state, and much is precedent vs written law. So it's rarely black and white (except when it's black and white). The type of thing that can cause expensive legal battles".
Bill H is right when he says "the concept of adverse posesion is is simple, that the details are very exacting and very from state to state. So any discussion of them is really meaningless ". Adverse posession is real but depending on the laws and courts in your state it can be expensive to prove. It is definitely - last resort.
Misfit, you noted that this was my first post. Over the years I've gotten so much good info from Breaktime, I was happy to see that there was a topic where I have some experience and could contribute. I'm a PLS with 30 years of experience, but I don't know it all (not even close) - every situation is unique. For the most part, the principals are the same state to state but the laws vary. The way that the courts interpret the laws vary. Going to court is rarely a slam dunk.
Surveyors have expertise in different types of work. If your surveyor does a lot of boundary work, she should be able to provide you with good advice and let you know if you need to contact an attorney (and if it comes to that - be sure it's an attorney with boundary experience). You might ask your surveyor about a "quiet title action" (your state may use a different term).
Best of Luck.
again I thank you for speaking up. everything and anything I can learn about this matter is to my advantage and it'll help me be better prepared in dealing with the end results. prior to starting this thread I had no idea how much was involved.in fact thanks again to everyone that has posted. I have much more confidence in my surveyor and my decision in hiring one as a result."If your neighbor believes the boundary is in a different location, have them hire another surveyor to check your surveyor's work."easier said than done. that would be at ->his<- expense correct?
Thanks for the info.
http://www.trimble.com/gps/index.shtml
interesting.....learn something new every day.
carpenter in transition
The "strength" of a survey is entirely dependent upon the points that are used as a basis.
There are "senior" and "junior" surveys, meaning GENERALLY that the older the points found, the more weight they are given in determining a point of beginning (POB).
The surveyor that you contracted with should have done enough research so that the end product is defensible in a court case. She should have, and I certainly would have, gone a good distance up and down the street to see if points in the area "agreed" with more senior surveys. I would also have gone across the street and checked these also.
This is quite a difference, and it may be that your adjoiners reluctance to have a survey ment that he knew your division lines were in error.
I would photograph all the points with the date mechanism engaged on the camera so when he destroys, or moves the points, you will have a record. The importance of ties will be illustrated when this occurs.
A little piece of advice. Try to work with your neighbor and not against them. Firm but reasonable works every time.
well looks like I have more homework to do. I need to find out where these control points on the main road are. I'm borrowing a camera from my brother so the photos of what she's done so far will be taken as well as the rest of the pins. are the concrete markers that are the POB for the other 2 adjoining properties also considered a control point for my defense? I know where they are and I don't see why they couldn't. I forgot to ask her about the 'ties' and I'm not sure if she'll do them so I may need the tips you offered on how to do it. I'll give you a shout if necessary."A little piece of advice. Try to work with your neighbor and not against them. Firm but reasonable works every time." believe me I have. this neighbor has been an arrogant 'something' in the past and I just ignore him. nothing is gained by getting into a tiff with him. I've learned from experience. in fact I'd be content with just leaving everything as is and whatever the survey reveals so be it. too bad he probably won't feel the same way but that's just speculation at this point. the truth will be know when he comes home. I will make every possible attempt to remain civil and hopefully he will to. thanks again Tom I greatly appreciate what you've told me so far. I can't thank you and the others enough! the last thing I wanted to do is open a can of worms by having the survey done but at the same token in actuality my neighbor is the guilty party. he dropped a fence that now causes harm to me and my property. I just want to protect what's mine.
When taking pictures, be sure to get stuff in the background in the shots, and try to line things up so the location of the pin can be easily determined from the photos.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
good point
I plan to do that
"Control points" in the roadway can be suspicious if the roadway has been refurbed in past years. We like to use roadways as they are clear of obstacles and allow long shots and the nails are easily recoverable. The right of way (ROW) of the road on both sides are usually a good basis as the subdivisions are usually based off of the center line, which can be easily translated into each side. We usually hold the curve data and ROW bearings as accurate and points therein as "monuments."
The drive still is bugging me. Ask your surveyor about any public utility easements (PUE's) or access easements prior to your metes and bounds for your purchase.
"The right of way (ROW) of the road on both sides are usually a good basis as the subdivisions are usually based off of the center line, which can be easily translated into each side. "USUALLY is the operative word.When I am ONE of the problems is that they laid out narrow roads and and did not provide any radius where the road segments join.My neibghor across the street corner point is in the middle of a bend in the road. Partially because the bend starts too soon because of the error in my corner and partially because of the radius of the bend..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
There's always a booger in everything. Don't know how old your subdividion may be, or what the basis for your ROW.
Curves in any ROW may or may not be concentric with the center line. I've worked many TxDOT jobs where none were concentric with the others.
However, for your road to be built and graded properly, there should be "curve data" for each ROW line, and the center line. I have seen right angle horse and buggy roads with a "curve" fudged in. These were usually "section" corners as they all had roads for field access around their boundrys.
Your county should have the information, or you can "match" subdividions on either side of the road to come up with "fittable" dimensions.
This was a lake developed in 1927 for summer fishing cabins. And it was "way out" in the country. Now is is being surrounded by subburbs.I got a copy of the plat map that was recorded with the county. However, it only shows the first and 2nd tier lots. but there are 3,4,5 tiers in places so there needs to be more maps, but that should not affect my immediate area.I also have a reproduction of an ar-tist drawing of what it is suppose to look like and on the back a reproduction of the plat map. It is marked with the surveryor's name and is basically the same as the filed map, but a little cleaner and a couple of extra dimentions. These where put out my the delvelopment company.But even at that the area is different from what was platted. I can quickly identify a couple of areas. One a different access road from that shown on the plat. 2nd tier and higher has acess to the lake by 6ft pathways between lots every so often. I know of at least one that that is not shown on the plat and another that is between the wrong 2 lots.The roads are all private***. The road and lake are owned by "The Developement Co" which is now what would be called a home owners association. But was not so structured in 1927.There is no ROW for the roads. The roads are bascially what is left over after the lots are plated. Most of the lots are irregular shapped and few common points so it would take lots of work to using the plat maps to work backwards and determine the actual point of the roads.Now the plat does show a nominal 25 ft for the roads. But that is even shown in areas where you can tell the gap between lots is changing.Where I am the 1 st and 2nd tier lots lines at the road are regular and parallel. But the one map does show a road changes direction there 60 degrees.*** The plat map says that the roads are not dedicated and they where never paved until about 20 years ago. They just had a buildup of oil and gravel over the years.That is, except for one short hill was paved with concrete. Back in the 30's and 40's Jackson County and Kansas city was run by Pendagrass political machine and he was in the ready mix business. Lots and Lots of his concrete when into public works.And he had connections to the lake and had the county pave that short section. But that was private proverty and there was a stink about it and so the roads where deeded to the county and a few years later the county said that they did not want to be responsable and dedicated them back..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
To all:
I find this thread to be very interesting. Had my own minor dispute concerning the property line and a neighbor using part of my property. The adverse possesion buisness is great for lawyers and not so great for homeowners. I finally ended up leasing him the land (really just a parking place) for a dollar a year. The lease did say specifically one of the goals of it was to preserve my property rights. Neighbor was a gentleman about the whole deal. By all means, stay level headed and try to keep all others level headed. Lawyers and cops and surveyers aren't cheap. A little comprimise (sp) by all can save lots of money.
To Bill:
But that was private proverty and there was a stink about it and so the roads where deeded to the county and a few years later the county said that they did not want to be responsable and dedicated them back.
I have never heard of any goverment enity giving back a road. Do you reckon this was some sort of backroom deal? What if the recipient(s) simply said, " No, we don't want it, you keep it".
It has been 25+ years since I looked at the deeds. Don't remember the time span, but IIRC is was a couple of years.But making them country roads ment that the county needed to do snow removal (however much that was done in those days) and grade and oil them.Since these where only interior roads and did not carry and through traffic there was no advantage to the county to have to maintain them.But yes it was all policitcal.One of the houses was called "The Sherief's house". I don't know if he owned it or it was a friend of his. But he brought out prisioners to work on the house.And several stories about which houses where envolved in suggling and bootlegging boze..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
That's a can-or-worms, which is the kind of problem I like to research.
First of all, your description is very clear and concise so the problems are straight forward.
A question: Who maintains the roads? Is it a Property Owners Association? Does the POA contract with your local county to have the work done, or is each owner responsible for the road out to the common center-line?
In cases like this, in Texas, if a county or municipality does not maintain the road, then it is "owned" to the center-line by adjoiners, and paid for by same. The problem with that is that some pay, and some don't. A lot of times when roads are in bad shape the county doesn't fess up to owning the ROW until the HO does research and finds out that they do.
You should have a clause or a "vacation" indicating that you are responsible for the maintainance, or a "vacation" of that piece of your tract that comprises 1/2 of the roadway.
Who patrols the roads? State troopers or local police? If the roads are a public menace and are not being maintained in a safe and responsible manner, you can petition your local government to require the roads be brought up to minimal safety standards with the proper signals and signage or you may hold the POA responsible for injuries and/or deaths that occur because of these conditions...including bridges. This is very important if school busses or emergency vehicles operate on these roads.
There are lawyers out there just looking for stuff like this. First, talk to your local county commissioner and get a good working relationship with him on this.
That's a can-or-worms, which is the kind of problem I like to research.
And never enough poles after the worm can expodes open afterward, either <g>
I'v got one of these right out my front door. When this subdicvision was platted out in 1950, it wasn't in the City Limits yet. The city had not established hard-an-fast subdivision rules yet in any event. However, certain State rules did exist, especially for emergency equipment access.
So, the developer 'fixed" that problem, by overlaying roads over some of the existing property lines. There was some time pressure as the City was in the process of annexation. The developer seemed to be unconcerned about fiddlilly bits like ROW (or disinclined to pay for the needed engineering work).
So, a paving company shows up with a paving box, and "private roads" connected the City's thoroughfares. Now, most of these were not much better than really long driveways--so, they've been a headache to the CIty ever since annexation made the roads City property of sorts.
One of the properties down the street from me is a more intersting case. Like virtually every other property here, it's two "lots." One of those lots, with a USPS address no less, is one of the intersecting roads. Always wondered if a public road confered adverse possesion, even if one was taxed as private property for it anyway.
For my shared bit of asphalt, I already know the answer. If I pay to have the curved segment marked out and recorded as a ROW, the city will be more than happy to execute an emminent domain process. Now, I'm going to have to strike it rich--I've four other parcels to record out, to make the property 'right.' But, that's life.Occupational hazard of my occupation not being around (sorry Bubba)
Now that's really weird. "Emminent domain" is usually an adversary process. It would seem to me, and have worked on similar parcels, that if you vacate the needed ROW extension, the city or county will take posession and dedicate it as ROW. Usually cities will "grandfather" subdivision specs for annexed areas, but new construction must meet the updated regs.
that if you vacate the needed ROW extension, the city or county will take posession and dedicate it as ROW. Usually cities will "grandfather" subdivision specs for annexed areas, but new construction must meet the updated regs.
Yeah, that was what I thought, too. But, when I went and talked to P&D about it, they said that they were taking a "let sleeping dogs lie" approach. The better to prevent "adversarial" relationships with extant homeowners. Like if half your property would vanish--but without recompense, as the City must needs tread with 6-league boots.
But, it one brought them a fait accompli, they'd bend over backwards to 'make it right' with any party improving their lot in life. (That, and apparently, em.dom. is their only modus operandi they can use, that does not involve annexation hearings and the like.)
It seems, like most things neighborly, politeness and manners first is the order of business.Occupational hazard of my occupation not being around (sorry Bubba)
No problem with the maintance. All this stuff with the county was in the 30's and 40's.The Developement Co (HOA) has been maintaining the roads as long as I have been here (1979).The development company has a staff, of I think 3 or 4 full time employees and several seasonal. Plus part time such as lake patrol.But unlike some HOA's the board does all of the management and control and jumps in for special hands on projects to. For example a couple of years ago the spillways where completely redesignd and replaced. That required lowering the water.Many of the board members helped with moving or safetying the docks.The only real problem with the Development company was that it was never structed with the ability to collect money other than a $25 anual fee and that was ever after they had sold a few lots. So some people pay $25 per lot, other per owner.So from time to time the board has to file a "friendly" lawsuite agains the homeowners to raise money. We recently had one to allow increasing the max yearly from $500 to $1000 per home. But there are also some other fees per dock, boat and motor.We are also a city and the city has a part time police with sheriff's backup.And the city is the one group that I am more concerned about. They have screwedup several things. I ahve not read the ordiancies, but will when I start a remodeling project, but from what I have read in the newletter they screwed up the building codes..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
it's bugging me even more. yesterday I spent some time assessing the situation and I now have some doubts as to the location of this questionable pin. is it possible for the surveyor to set a temporary pin until all points are located and then go back and make an adjustment? the reason I ask is if I sight a line from where I ~thought~ the corner should be it's not exactly a clear shot to another stake she set further down the line. now this is just from my untrained eye so keep that in mind. if it is possible then why would she need to move it so far? a couple feet over if even that would have given a clear sight line.I did notice a couple stakes with ribbons out on the road as well as a ribbon on the other neighbors concrete POB. so it does appear that she's using a several control points.the road was repaved about 5 years ago. all they did was grind the surface and repave. no major rework or widening was done.
Standard survey proceedure is to "traverse" around a tract "locating" pins and other needed topography such as fences, structures, etc. that may have a bearing on the validity of the survey. This traverse is taken back to the office for analisys and the needed calculations to verify the located points. She then may return and set the necessary pins from the traverse and verify distances and angles on the ground where observable. If these agree then she may write your new metes and bounds and provide a sketch to you.
When she does the walk-around with you, I'm sure she'll explain things for you. I forgot to mention that in the disputed area it would be a good idea for her to set some intermediate points if the entire line is obstructed from view. It'll help with your fence and tree planting. She could do this with a few simple calcs from any set-up in that area.
cool so it is possible.then I'll just sit tight for now and wait until the end of the week when she's done. or until the neighbor returns and ?????I did ask her to set a few intermediates so that the tree guys will have something to work off of when they run a string line.
Just out of curiosity, since it has been 40 years and several generations of technology since I worked on that survey crew, what equipment is normally used for standard surveying these days. What I worked on was layout of a medium sized earthfilled dam. I often see surveyors around town with only a single instrument on a tripod (I assume a laser transit) and a reflector set a couple of hundred yards away. No rods or chains. I assume that the instrument measures the distance and the rise or fall angle (don't remember any terminology...) and then calculates the distance or gives a readout from which the surveyor can calculate the distance. Anyway, I would appreciate a short treatise on modern surveying techniques with minimal personnel.Thanks
Good questions, and useful for all.
Modern equipment uses infared lasers to obtain distances. Where we used to use chains, plumb bobs, now, prisms (which reflect the infared laser) are placed over points to obtain angle, distance, and the correction to horizontal.
The guns are now called Total Stations (TS), and data from them is stored in Data Recorders, which are hooked up to the TS and recieve the data from angles, distances, and elevations observed by the unit.
This data may be down-loaded directly to a computer, and plotted as needed, after the information is manipulated as desired.
Points still need to be set, but that is accomplished by setting "chaining points" with the prism and then going the remaining distance to set the required point.
Usual proceedure is to set a prism on a tripod on each point, backsight and foresight, set the TS on the intermediate point, and turn angles and observe distances in feet and meters to minimize errors. These are not only recorded in the data collector, but also in a field book. The field book gives location, date, temperature, weather conditions, and personnell involved in the survey along with a sketch and angular and dimensional observations of the traverse or elevation set.
Then we drink beer....
"Very clear and concise explaination"I concur
No question about it
oh yeah it helped immensely! Your post along with a couple others helped clear up some of that muddly muck ;)I wouldn't be surprised if the hand held device that my guy has seen was one of those 'tens of thousand dollar' jobs. He seemed fairly knowledgeable about all the ins and outs of this type of work. "But in spite of it all, you still need a starting point, deed research and a licensed surveyor to set your corners. That's where the expense comes in. Our policy for off-the-cuff estimates of boundary work is to start at $1 per foot of the perimeter and work up or down from there depending on how much information and field evidence is present. So for a square acre, roughly 208 x 208 feet - we would estimate your survey costs at about $840. The bigger the parcel, the more "pre-research" we will do before giving a cost estimate."This last bit is even more helpful. You answered a specific question for me before I could ask it. I'll admit I felt I was getting hosed a little with the $1000 price based on only wanting the location of 2 points and having all the legal legit dimensions available. But having no idea what the going rate is doesn't justify it. The $1 per you mention is what removed the uncertainty. My parcel is just shy of 6 acres and the 500' line I need the corners set for is about 700' from the nearest concrete marker. Using simple math at least shows me her estimate isn't out of line. I'll sleep better now ;) Great post Jon
thank you
To work accurately enough for surveying, you need to have two GPS units communicating with each other. One is placed at a known reference point, and the other then figures it's "delta" from the first. With this scheme it's possible to be accurate within an inch or so, perhaps down to millimeter accuracy.
This isn't your basic Garmin unit.
To sum it up, most or all of the below has been mentioned before. GPS can be exact to the millimeter and there are three ways to do that.
1. Military equipment, the signals from the satellites are in part encrypted and with the right gear you get really good readings live.
2. Time, by following several satellites and their movement across the sky for a long time you can determin your position. ( 1 to 24h depending on your needs, placement and satellites crossing) This spot could then at some times be used as:
3. A known basepoint, this can be either a monument where you place a transmitter of your own or a fixed basepoint where a city, university, surveyor or others places a transmitter for regular use (I assume some of these has been turned off for security reasons the last years).
One of the above is not an option and the others will be expensive because of either paying for time or investment. I know a few surveyors who have had their base-transmittors stolen while doing work so if you see extra bolts by a monument they may have been put there to have something to chain the transmittor to.
Another possible problem, as mentioned, is going from GPS-coordinates to a local grid. This can be easy, but in some places it's a great enormous PITA.
Might have forgotten something but I'm sure I'll be corrected. ;-)
Good luck with finding the markers, around here it's illegal to move or hide them.
GPS is really questionable. The main problem is that the military (which maintains it) deliberately makes the signal inaccurate to prevent hostiles from using it. If you take a handheld GPS receiver and stay in one spot, you can watch your position slowly change. Interestingly enough, in times of war, when there are more hostiles than usual, the military turns this dithering off because they need an accurate signal. The dithering can also be defeated by means such as differential GPS, where a ground transmitter supplies corrections to the signal.
There are GPS receivers that are very accurate, but they aren't cheap or handheld. And no GPS receiver is extremely accurate when it comes to altitude.
reason your position appears to change is that the longer the reciever remains in one spot, the more accurate the reading gets as it takes down more info from satellites. A reading that is within thirty feet on a quick spot check can get to within a couple of feet if you leave it set for 24 hours
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
That's not been my experience with a handheld unit. They drift because the military deliberately messes up the signals.George Patterson
That was quite true, however the feature Selective Availability (SA) is now disabled. The following it quoted from http://en.wikipedia.org/wiki/Gps"In the 1990s, the FAA started pressuring the military to turn off SA permanently. This would save the FAA millions of dollars every year in maintenance of their own radio navigation systems. The military resisted for most of the 1990s, but SA was eventually "discontinued"; the amount of error added was "set to zero" at midnight on May 1, 2000 following an announcement by U.S. President Bill Clinton, allowing users access to the error-free L1 signal. Per the directive, the induced error of SA was changed to add no error to the public signals (C/A code). Selective Availability is still a system capability of GPS, and error could, in theory, be reintroduced at any time. In practice, in view of the hazards and costs this would induce for US and foreign shipping, it is unlikely to be reintroduced, and various government agencies, including the FAA, have stated that it is not intended to be reintroduced.The US military has developed the ability to locally deny GPS (and other navigation services) to hostile forces in a specific area of crisis without affecting the rest of the world or its own military systems."
That's why you use the fixed reference. If you have one GPS on a benchmark, others nearby will be dithered the same (and atmospheric distortions will be the same), so that relative measurements from the benchmark will be quite accurate.(And the reason that dithering has been turned off during the Gulf wars is to allow the military to use non-military GPS units that don't know how to undo the dithering.)
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
are they turned off now?
I dunno. I don't keep track of it that closely.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
military (which maintains it) deliberately makes the signal inaccurate
It's also germane to remember that military "accuracy" varies. For land navigation, you really only have to be accurate to about the width of a person, somewhere between 1m & 0.5m. For unguided projectiles, you really only need be accurate to 0.25 to 0.5 CEP--which varies by what is being used to lob the projectiles.
You start driving ships around, and you only really need the "triangle" of error to be within the ship's dimensions, even a bit more than that--anything closer than a shiplength is pretty high-tension for all parties.
And those spiffy dashboard units? They only need to be as accurate as half the ROW (and the graphics are 'cheated' to match in any event).
Occupational hazard of my occupation not being around (sorry Bubba)
Standard GPS averages 3-20 meters accuracy depending on the number of satellites in view and other factors. Most people assume GPS is more accurate than it really is and there are lots of misconceptions especially about military vs. civilian receivers. A regular GPS receiver would not be very useful for laying out lot lines.
Surveyors can use differential GPS (DGPS) where the signals of two receivers are compared to average out the uncertainties. With DGPS it's possible to have accuracies of 1-3 feet. Using multiple DGPS receivers with independent base stations can get the location accuracy down to inches, but those signals not available in most places.
I googled DGPS and found some interesting material here
thanks for mentioning it.
Did he take you to dinner first, with plenty of wine and soft music before he told you that?
"Dammit, grab that shore line and bring it to the sky hook." ;-)