How accurate are surveyors?

Question

Hi, does anyone have any idea how accurate surveyors are? For instance when they divide land into say 5 acre sections and set the boundaries for the 5 acres is there a plus or minus for a margin of error, and what would that margin be?

Answer 1

A lot depends upon the tract size, the terrain, ground cover, topography and number of corners.  If you're talking about a square 5 acres, I'd expect the accuracy to be within 1/20th of an acre or less at least.  I've seen small building tracts in cities down to the 1/100 of an acre.  You can bet that high priced land in places like Times Square is measured to even less than that.  Accuracy would be more difficult were you surveying a 1000 acre tract in a tree covered, mountainous area that had irregular boundaries such as following streams or ridgetops.  You'll notice that most abstracats and deeds will also say something like "5 acres, more or less".  The "more or less" gives some leeway to the seller and surveyor, but there are limits.  For instance, I couldn't sell you a 5 acre tract that actually measured 4 acres.      

Answer 2

Surveyors are supposed to be accurate.  That's what you are paying them for.   And if they aren't, your state probably has an agency where you can complain if the surveyor does not fix a survey on which he made a mistake.

It's more difficult when you are dealing with larger pieces of land, but if I were you I would get all relevant information from the deeds and other documents mentioning the boundries, and do my own measuring, to check the surveyor's conclusions.   If the survey then does not make sense to you, first try talking directly with the surveyor for an explanation.

Answer 3

A surveyor is very accurate and with the new technology out now, they can measure distances within the accuracy of 2 hundreths of an inch, Even without technology and doing the survey with rods, stakes, instraments and tapes, the surveyors are to be accurate within one half of a percent, so in a large field you have have some margin of error, but its really small and dividing an area into sections is relativly easy compared to surveying a field and making a topography map of it. Anyways, most modern surveyors use gps survey equipment that is unbelivable accurate.

Answer 4

Land boundaries are often marked by a round steel stake.  Likely a good surveyor could accurately replace the stake.  When a steel tape is used for a distance measurement, the sunny and shaded portions are corrected for differential expansion due to temperature.  However, no one is perfect and even the land may be moving slightly.  

Answer 5

Using GPS techniques AA accuracy is .02 ft for both horizontal precision and vertical precision.  This can be further refined by remeasuring  and remeasuring.  .02 feet is equal to 1/4 inch.  This converts to .01 acre accuracy in a mile long run, .005 acres in 1/2 mile, etc.

With good controls using a total station for measurements this will also provide better precision.

Answer 6

Disclosures astronomical, mediantes publications and articles in the media?

Many of the times are sophisms (false arguments and reasoning defective), which pass unnoticed among the public that enjoys them.

His conscience in action: Buy the guide to observe the sky of our Solar System, published by SCIENTIFIC AMERICAN - Brazil, and see beyond the stars who say mirabolantes be suns, the Galaxy said Antena 2 in different observations.

There is no other way, astronomy is a impostora.  

Answer 7

Surveyors are accurate to 3 significant digits on area, and 4 significant digits in individual dimensions.

But,  then we have a little bit of a problem when we describe where on earth it is. Many disputes arise because land is registered based on well defined reference points far from the land. But with any shifting of the defined reference point, even a few cm can effectively distort the whole property map of a municipality.

From this we have to say that reference to well defined reference points will be fairly accurate at the time of a survey, but will not remain accurate forever.  Seismic activity or even erosion can change not only well defined reference points, but surveyors stakes can move  a bit.

Our land was originally surveyed using magnetic compass bearings which means that with the shifting of the magnetic north pole, it is no longer close to accurate. A re-survey had to be done using only well defined reference points. But nobody lost land. All that happened was that our legal descriptions changed.