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Something older surveyors who have had a long career sometimes deal with…
Posted by i-ben-havin on July 13, 2018 at 4:34 pmAfter an interesting discussion with a county property appraiser today I would like to know others take on the following:
For sake of discussion lets assume around 1965, in the early career of a surveyor, his/her equipment consisted of a 100 foot steel tape, and a 1 minute transit. And, lets say at the beginning of the surveyor’s career he/she goes out and runs a traverse around an entire section (PLSS, 1 mile square +/-) from found monument to found monument, etc. The surveyor then computes and draws out the entire section, and over a period of time conducts surveys and prepares metes and bounds legal descriptions eventually covering the entire section. At that point, one (the county property appraiser for example) could take the legal descriptions, lay them all out, and like in a puzzle the pieces would fit perfect. There would be no gaps. No overlaps, etc.
However, around 2010, having upgraded his/her equipment to 1 second total station and dual frequency GNSS, the surveyor goes back out and re-runs the same section. The surveyor then computes and draws out the entire section. And, not surprisingly, all the dimensions changed. What to do?
Should the surveyor be expected to continue using all of his/her old (original) dimensions for the entirety of his/her career? Notwithstanding the fact that other surveyors would come in and understandably use their own dimensions, however, is there some expectation that a surveyor can not or should not change his/her own dimensions?
In addition to typically showing both the field (current measure) and deed (original) dimensions on the map what about further subdivisions of an “original” parcel. Should the surveyor be expected to describe the new splits as would be determined by their deed (original) dimensions?
At what point is it ok for the surveyor to begin using the more accurate new measurement data when preparing legal descriptions, whether for resurveys of old original parcels or for new splits?
(Perhaps some surveyors started out with a compass and chain in 1800’s, then upgraded to 1 minute transit as soon as he/she could purchase one. Equipment and methods are always changing, and legal descriptions today mostly do not resemble those from the 1800’s. NOTE: I can recall looking at a tax map back in the 1980’s from a county in an Original Colony State, and many of the adjacent properties were depicted with dual lines because the dimensions were different. The mapping people had no idea how to map adjacent parcels with different bearings and distances even though on the ground there was a common boundary.)
thebionicman replied 5 years, 9 months ago 16 Members · 20 Replies- 20 Replies
Put record and measured on the plat. The tax map GIS folks can use whichever they choose, either the original or what they believe is more accurate.
Remember that for property corners and lines “correct is an identity, not a distance.” Monuments rule over measurements.
.It’s a very interesting discussion to be sure. I was tasked( read: suckered) with “Cleaning up” the county parcel map when I was hired on with the county. This was presumed to be a 5 year or more project that would keep me employed gainfully( while ruining my ascending career…another story…) and get the county ” up to speed” with the rest of the world and other counties.
I have been asking this same question, about the changes in the distances, directions and dimensions, and how we remedy the maps to reflect recent plats filed, lots consolidated, splits, etc. No one where I worked had any idea. Other than I should know what to do because I had studied some of this in ” GIS” school.
Other people I turned to, far smarter and longer in the teeth, and superior in knowledge, judgement, mentioned that the original measurements, unless grossly miscalculated, stand. They have been relied upon since the original surveys, and to re-survey and ” adjust” everything would be monumentally expensive, not to mention create a tremendous upheaval in the way this whole system works.
It’s a catch 22 to the expectation of superior and exceptional work expectation, and then what ends up is the reality of what we have.
And every time a new plat came across my desk, to draft into the GIS, I would always hesitate before running the directions and distances into the drawing I was creating, to determine how I would frame the next question on ” How are we going to address the change in acreage for the assessors office……?”
I’m eager to see what the smarter, and still wiser people are doing so I can learn more about this process.
Measurements are evidence. As our ability to measure improves we should be able to report a more reliable number. That doesnt change what a person owns, it just gets you closer when looking for the monuments and other evidence.
Why would you treat your prior measurements any different than a different surveyor’s measurements?
I often downplay the importance of measurements for our profession, but if you measure something it is inappropriate to report a distance other than what you measured. Your state probably has minimum requirements for precision and your certification probably says something about the survey being accurate to the best of your abilities. If you are not reporting your best guess as to the true value of the measurement you are not meeting these requirements.
A survey should not be reduced to a meets and bounds description, but if you must, it needs to make clear the relationship between the new measurments and the old.
We are retracement surveyors. We are to follow in the footsteps of the original survey.
The old surveyor measures 10 chains between two monuments of record. Each link is 0.66 feet. Did he round off the last link? I’ve never seen a measure of 10 chain 1.5 links. so that begs the question. What way did he round it? Up or down? How was the chain orientated when the measure was made? Suspended or dragged?
We observe the same two monuments with a robotic total station in 2018. We measure 661.35 feet between them. Who was right? Both were right.
Here is something to try and communicate to a layman. Both measurements are right and wrong. We can never know the true measure between two points. The line is being represented as best as we can describe it today. What matters is where the two points are on the ground in reality.
That’s an oversimplification, but accurate to say.
Edited: As to changing distances, it should only be done when original evidence is found. Extrinsic evidence set after the fact is just that, outside evidence of where joe blow thinks the corner is. It is up to you to verify that report as being accurate or bad.
- Posted by: aliquot
Why would you treat your prior measurements any different than a different surveyor’s measurements?
This is different in different parts of the country. For instance, I know from Kent McMillan that in Texas, every time you survey a line, you put the current measurements of that line, no matter how minute the difference is in the record. In Tennessee, it is almost considered sacrilegious to resurvey a tract and come up with something different than you did before. I am somewhere in the middle. I am certainly not going to come up with a different mathematical answer than I did last month on the same line. However, I might not hold the same math on something I did 5 years ago either.
We get some resistance from old school guys. I had one fellow ask me why I called him wrong over 0.05′. I told him that matching that well in a half mile was calling him right.
- Posted by: Tommy YoungPosted by: aliquot
Why would you treat your prior measurements any different than a different surveyor’s measurements?
This is different in different parts of the country. For instance, I know from Kent McMillan that in Texas, every time you survey a line, you put the current measurements of that line, no matter how minute the difference is in the record. In Tennessee, it is almost considered sacrilegious to resurvey a tract and come up with something different than you did before. I am somewhere in the middle. I am certainly not going to come up with a different mathematical answer than I did last month on the same line. However, I might not hold the same math on something I did 5 years ago either.
I am licensed in both Tennessee and Texas. I always show what I measured and what the record is.
I am not sure what you mean by a mathematical answer. The corner position stays the same, but if I am signing a document I am certifying my boundary opinion and my measurments. I can’t certify a distance that disagrees with my measurement.
It really boggles my mind that there are still surveyors who think that reporting a more accurate measurement means disagreeing with the previous surveyor. A disagreement is when I put a corner in a different spot. Not when I measure better than you because I have better equipment, or when I measure worse than you because my level bubble was out of adjustment.
When I find two original GLO stones at 40.5 chains instead of 49.0 I don’t think of the original surveyor as being wrong. I just think that I can measure better.
We are talking about boundaries here not high precision engineering. The important thing is the location. The measurments are way down on the list in terms of importance.
There is the spot you located in the dust. Then there is the center of the top of the bar that you drove starting at the spot in the dust. Those two locations will be a hundredth or two or three apart horizontally and some number of arc-seconds different relative to some other monument.
The 0.04 we discuss with great frequency here was first mentioned by me over a decade ago on a predecessor to rpls.today. The situation was one where another surveyor measured between two bars I had set a couple years earlier and reported the distance was now 0.04 longer than what I had reported. Using either measurement, the end points would still fall on the survey caps.
Surveyors have enough difficulty with comprehending uncertainty that it is no wonder the general public cannot grasp the concept.
Bill 93 and a few others are right on. A surveyors measurement is evidence and you cannot expect the same exact measurement when using different equipment, different procedures. This is why we use monuments which are evidence of our measurements. The monument holds. On plats I show measured and deeded.
‘They have been relied upon since the original surveys, and to re-survey and ” adjust” everything would be monumentally expensive, not to mention create a tremendous upheaval in the way this whole system works.’
Which reminds me, the tide line in the Gulf of Mexico is – hands down – the best fishing spot.
I like seeing actual measurements even if they’re very close to record, at least you now the last guy actually measured it. It’s suspicious when you see perfect record, makes you wonder how close it is. Just report what you got.
The only accurate map is the full-sized map out there on the ground. The physical surveyed points. All of the measurements that have been made are nothing but attempts to put on paper what is actually out there on the ground. The paper maps contain natural, instrumental, and personal errors. The degree of positional error or distance/bearing error does not override the stuff out on the ground.
It does provide a bit of a problem for a GIS person who doesn’t understand that, especially one who thinks everything to date ought to match perfectly. In addition, some GIS people might not understand that aerial photography scale changes depending upon the variation of flying height above the ground caused by terrain elevation changes–very substantially in some cases.
Show both measured and record distance, and proportion the record distances.
Is with all things survey, you aren??t calling the previous work incorrect, rather, you are calling out that your distances are in (usually slight) disagreement.
The tricky thing in my opinion, is GPS survey breakdown of sections. No longer do you have measured and record distances, as everything just magically fits, often with no statement on what was held, or the method of adjustment utilized to fit it all together.
- Posted by: [email protected]
The tricky thing in my opinion, is GPS survey breakdown of sections. No longer do you have measured and record distances, as everything just magically fits, often with no statement on what was held, or the method of adjustment utilized to fit it all together.
GPS is just a space age measuring device. If the required information is not given they are doing it wrong.
About 10 years ago, I started putting this standard description of the ( ) placed around record or previous dimensions in camparison to measured dimensions:
” ( ) – Denote record plat data depicting the same line on the ground as retraced by this survey”.
In 10 years, I have not had ONE call from a lawyer, title company or engineer informing me that “your survey is wrong because you did not measure out the dimensions stated on the deed”.
I have a few comments about the property valuation for real estate tax purposes, which is influenced by frontage and area. I’m a justice of the peace in Vermont; property taxes are done at the town level. I’ll outline the process of assessing value.
First, something major happens to create a new area, such as subdividing a property. The listers or assessor use the best information they can obtain to estimate the frontage and area (frontage is particularly important if the property abuts a lake). If the new property, probably with a new survey by a land surveyor, disagrees with adjacent properties, the numerical values for the acreage and frontage will be used in placing a value on the property, and the revision of the tax map will be left for the next time the town votes to spend money on a tax map update. Chances are good they’ll keep putting it off in hopes a grant for the purpose will come along from the state. (There might be some towns that are better organized than this, but I haven’t encountered it.)
If the survey reveals that an abutting lot must be larger or smaller than the assessment record for that property indicate (called the lister card) the listers or assessor could, on their own initiative, inspect the property and change the value. But they are not qualified or equipped to survey it, and can’t order the property owner to get it surveyed, so chances are the obviously wrong values will be just left alone. If the area is too small and causes the abutting property to be undervalued, the property owner has no motivation to do anything, so nothing will happen.
If the abutting property is too big on the lister card, and the property is therefore overvalued, it would be up to the property owner to get a survey and grieve his/her property valuation. The lister/assessor might agree with the owner and change the lister card and value for that one property. If the lister/assessor stands fast, the owner can appeal to a board consisting of the justices of the peace, town clerk, and select board. I’m on that board.
There is no organized program to propagate any discrepancy that is discovered to abutting properties; it’s essentially up to the property owners to complain if it is to their advantage to do so.
“At what point is it ok for the surveyor to begin using the more accurate new measurement data when preparing legal descriptions, whether for resurveys of old original parcels or for new splits?”
As soon as they make the new measurement. The measurements are for the purpose of aiding in the discovery of the monument location.
Have you ever encountered a situation where you “corrected” a monument you set years earlier? For example digging up a couple of undisturbed buried nails from a long ago adjusted traverse used back in the old days to turn a calculated angle and measure a calculated distance to set the monument in question. And, now finding the monument is not quite where you calculated it to go back in the day. If the monument is setting harmless in a location where no property line or building line offsets would be affected if you wished to “correct” your recently “found” monument, would you in fact consider disturbing the found monument in order to place it where you calculated it should go many years earlier?
What rules apply here? What if the monument has obviously been moved 5 or 10 feet, and there is a fence built to it? What if it’s only 0.15 feet from where you calculated it should go back in the day (assuming years earlier you had actually carefully set it at the precise intended spot)?
To take the position you would “disturb” the current position of the monument to correct it to a position calculated from an old adjusted traverse (error of closure better than 1:10,000 back in the day), how would this differ from adjusting it using the best current available position data which would be GNSS derived? Is there a definite mandatory ethical reason to leave the monument where it had ended up after all the years even if you have better information which would allow a more accurate placement? And, which would allow you to set it where you had always intended it to be set originally, but were limited by the capability of the equipment?
If I blew it and failed to meet the standard of care I’ll talk with the owners and clean it up. If the monument has bern disturbed I’ll reset it.. If I find a pin I set in 79 with my T2 and chain and miss by 0.15 I’m likely going to leave it alone.
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