Bearings & Distances on Plats

You make an excellent post

The problem is that it is difficult to find anyone willing to admit that we really are terribly sloppy compared to the data we claim on our plats. That is the number one problem. Living in denial. Deep down we all must admit to ourselves how silly it is to claim perfection all the time. Back in the day I had a college professor who claimed he could read his slide rule to six decimal places. He said it over and over as if merely saying it over and over would make it true, just like politicians when their lips are moving. Today's button pushers get numbers to incredibly precise readings and then actually believe those are the only possible numbers that could be obtained. They still do this even when they take multiple readings and get slightly different values. Come back tomorrow or next week with the same or different gear on still or windy days and get that same "correct" number every time. Yea, right! Time for a John Francis moment.....*$*##&*$*&*^^*(

>I am wondering, though, if a blanket statement regarding RPA would be a good idea on the plat?

I think that best practice would be to list the coordinates as grid coordinates of the SPCS (and ellipsoid heights) of all markers shown on the plat and give the standard errors of the N and E values. In practice, with GPS control a surveyor should be able to work to a standard that would easily hold the standard errors to under about 0.02 ft.

The estimated accuracy of the coordinates are then explicitly stated on the plat and the bearing and distances act as checks on the coordinates or as an alternate means to restore missing markers, but with the information in hand as to the uncertainty of the coordinates from which the bearings and distances were calculated in the first place.

I have yet to find a more efficient way to annotate boundary markers in a small lot subdivision than just by giving an i.d. number for the markers and setting out the coordinates in a separate table.

This is precisely why math doesn't hold for boundary. The original survey holds. And a survey happens on the ground, with physical monuments.

The fact that our math can never perfectly represent our survey is annoying. Sometimes we get confused because our math comes first in our workflow. But, the first division happens with monuments on the ground.

And, I agree with Kent. Coordinates with 4d (don't forget the metadata) and precision would be great.

You make an excellent post

> we really are terribly sloppy compared to the data we claim on our plats

I think I agree with what you're saying, but would somewhat qualify it further. I think we can have a certain amount of comfort in the RPA of our data if we obtain a working knowledge of LSA and use honest scalars and setup errors. What I don't think is that B&Ds are the best way to represent the data, especially when RPA is taken into consideration.

I agree with Kent's post below, coordinates, ellipses, and a smattering of metadata would be very helpful (to the right surveyor). Two of the colonial states I am licensed in, though, tack on a truckload of superfluous (antiquated) statement requirements if you list a state plane coordinate for the corner. Data such as: NGS monument used, quadrangle(s) the tracts are on, etc. Some of the requirements are benign (such as quadrangle) others are N/A (such as NGS monument).

See my post above about antiquated requirements, this is what led me to the blanket statement thought. I agree with pretty much everything you've said, except for the 0.02'. I have done a lot of work where this is attainable, and a lot where it isn't. Some of the examples would be timber tracts are between 500-2000 acres in rural WV, NC, KY, etc. One can still do a "good job", though, using best practices. The expected accuracy can drift out to 0.3', however, when traversing a few thousand few along a rough ridge that is absolutely polluted with tree cover.

Why don't we also increase our perception of being the smartest person on earth and insert the OPUS solution on the face of the map (in meters). That will make us look even smarter. (yea right)

Lots of numbers and wording surely benefits our client, he will surely think that he has the best survey in the world with all of this stuff on his survey even though he has no clue of what this means.

Personally, I am not motivated to show state plane coordinates and scale factors and such on a Land title survey that just confuses the client. I prefer to do a survey to the minimum standards and let the next guy have at it.

Just my 0.02

Randy

> Lots of numbers and wording surely benefits our client, he will surely think that he has the best survey in the world with all of this stuff on his survey even though he has no clue of what this means.

Well, the folks that the uncertainty estimates are for are the future surveyors who will be in the position of reestablishing boundary markers in the subdivision at some future date. If a surveyor is going to make their job easier by listing the coordinates of the boundary markers as originally set, then it is simple enough to add the standard errors of those coordinates if he or she is using Star*Net or some other least squares survey software to compute the coordinates.

> Personally, I am not motivated to show state plane coordinates and scale factors and such on a Land title survey that just confuses the client. I prefer to do a survey to the minimum standards and let the next guy have at it.

In the case of a subdivision plat, where the purpose of the coordinates are for the benefit of other surveyors and where the additional effort required is relatively small, it's just throwing useful information away not to include it in the record.

> I'm sure we've all heard the stories about the lawyer grilling someone about the quality of the instrumentation, measurements, etc. Or if there is a typo on the plat that the whole thing is junk. I honestly haven't heard of anyone being subjected to a line of questioning such as this in the past decade. Lawyers usually don't know enough about surveying to go this route anymore.

I'll be the first to admit that I am a young surveyor and have much to learn, but I have had the great experience to testify as an expert in a few boundary litigation cases. Not one time have I been questioned about measurements, accuracy, precision, etc. Every question I've answered has pertained to the legal principles supporting my decision as to the location of that boundary. The numbers are just guides.

I agree 100%. I've only testified twice, and I was pleased with the questioning. It was rather pertinent to meat of the subject (go figure). My old boss testified a lot more than I have, and he said he's never seen the theatrics, either. We were maligned with a lot of "what if the lawyer asks you this/that" in college, and in retrospect I think 90% of it was intended to be "character insurance" if you get my drift.

I care about the numbers too, though, because they are usually the first thing a fellow surveyor has to judge against in non-recording states. They aren't usually privy to the depth of research/recon/interviews that we have conducted, but they can usually quickly tell if we botched a measurement. I tend to lean on the side of too much data on the plat. One thing I borrowed from an old surveyor a long time ago is to list "deeds of interest" on the plat if it was a confusing bit of research. I do this because when I do get the "I'm not agreeing with you phone call" its usually because I found deeds that they didn't. Its only came up two or three times, but if it can keep people out of court...

You make an excellent post

There is a much better manner of expression than bearings and distances. Monuments. ..