de minimis

[Scott]

NOTE:
THE LENGTHS AND CURVE DELTAS SHOWN BRACKETED BY DASHES, E.G.-XXX.XX'- OR -XX°XX'XX"-,
ARE NOT MATHEMATICALLY ACCURATE AND DO NOT MATCH THE PARCEL CLOSURE CALCULATIONS
SUBMITTED WITH THIS MAP. THE TRUE VALUES OF THESE LENGTHS AND CURVE DELTAS
HAVE BEEN MANUALLY OVERRIDDEN SO THAT “THE PARTS ADD UP TO THE WHOLE”
AS REQUIRED BY THE JURISDICTIONAL SURVEYOR.

I am sure this has been discussed on this forum before, but I couldn't find the posts.

Please add comments/suggestions/opinions.

“de(sic) minimis
Di(sic) minimis is something that is very trifling or of little importance. Usually refers to something so small, whether in dollar terms, importance, or severity, that the law will not consider it.”
Cornell Law School, Legal Information Institute

[SueDonim]

As I was doing the same thing with a couple of curves on a ma in CAD many years ago, one of my mentors asked me, "What is the radius of a curve where one arc second equals 1/100th of a foot?"

After I had calculated it, he asked, "Why are you chasing your tail try to make the math on a set of 30' radius curves 'add up'?"

[ekparian]

For me the answer is simple. The acting city surveyor when asked about his comment stated he would refuse to sign the final map until the closures added up. I spent about 3 hours offsetting boundary lines and internal lotlines trying variations between .003', .001' etc. And then revising my curve deltas and distances, then revising my closures and comparing cad to closures. Anyone with common sense would let it slide. I even tried to add a similar statement to the above "due to rounding some of the intermediate dimensions may not add up to the overall dimensions". The note was frowned upon.
Said city surveyor wanted my closures to be to the hundredth and full second rather than to the thousandths and partial seconds because that's how the map is laid out.
I felt it was easier to appease the acting surveyor than make my client deal with this overreach.
It was ridiculous but I got passed it.

[hellsangle]

What's that ol' cliche ??? Can't find the forest for the trees?

This is to the point of - incompetence! Run the math. It doesn't matter when it comes to error ellipses.

Doing such crazy calcs is like "map" pincushions! Absolutely insane. (Sounds like it is an engineer too caught up in numbers.)

Crazy Phil - Sonoma

[hellsangle]

Oh! And another reason to go Surveyor to Recorder!

[D Ryan]

You couldn't overuse the words ridiculous, incompetence, insane .. too much for this situation. Wrong person in the wrong job.

[Jim Frame]

I don't understand the need for the note -- why not just show measured and record?

[Scott]

Jim, the jurisdictional Surveyor wants me to change certain courses so that utilizing addition/subtraction (simple Arithmetic) the “parts add up to the whole”. I am signing the survey is "true". If I randomly change some courses (from what is submitted on the Parcel Check Closure Calculations) to satisfy simple Arithmetic, I feel a note is warranted.

Pretending I am a future Surveyor laying out this FM (pdf attached) in ACAD:
From the data shown on the FM, I know Lots 68 and 71 are perfect rectangles and I lay them out accordingly as shown.
Then I proceed to layout Lots 69-70 to the west, using the bearings and distances shown on the map.
The west line of Lot 69 calcs to be 84.80’
The west line of Lot 70 calcs to be 85.21’
And because the Lane is not perpendicular to the Avenues, the west line of Block 110D1 calcs to 170.02’ (0.01’ more than the sum of the two lot lines).
Geometry, an amazing thing!

This has bugged me for decades and I have been successful over the years in changing a few minds about checking "parts to the whole" without taking into account rounding and geometry. There are 3 jurisdictional Surveyors I deal with who still check this way.

I do not want to change anything from true.

What about this (without changing anything from true):
Note:
All data on this map is true (to the precision required) as stated on Sheet 1 and exactly matches the Parcel Check Closure Calculations submitted with this map. It is known that by only utilizing addition/subtraction (simple Arithmetic), some parts do not add up to the whole. However, it is understood that by employing the angles of the segments in conjunction with all the adjacent courses (taking the Geometric figures as a whole), the parts do add up to the whole to the precision required.

The funniest thing is that they never, ever, find all of them and it just seems to be something that if they happen to see one, they mark it.

[Jim Frame]

This is the note I use:

"The sum of the individual parts of a given line or curve may not equal the overall quantity due to rounding."

It works around here.

[Scott]

I like it. Thanks!

[falcon]

I like it. Thanks!

I'm curious @Scott, I've never seen those two dashed lines behind the R/O/W lines. Are those two sepearate easements? perhaps a sidewalk and then a utility?

[Scott]

Yes, two easements. 10' PUE and a 6' Planting Easement

[CBarrett]

When I run into a boneheaded mapchecker who gets hung up on rounding and the sum of the parts within 0.01 or 0.005, I make them happy. Some places have zero tolerance rules, which seem to come from inexperience.

It is de minimis either way. I do what it takes to make it go away fast.
If I have to change a 0.06' to 0.07' in two places on the map and my math still closes within 1:20,000 or better, I expect the next surveyor will not lose their bippies over having to deal with 0.01 in rounding residual.

If someone wants to sue over that, I've had enough math, statistics, logic and other 'learning' to competently explain why I did what I did and how it is acceptable and immaterial in a case where I applied it.

If I don't fight it it passes easier, like a good refreshing dump.

[Chiara]

I've run into this issue on a number of subdivision maps in a jurisdiction that will remain nameless. On the latest map I'm working on, I received a letter, cc'd to my client, claiming I don't understand cogo. We talked in circles on the phone about it. I tried to explain to him that over a number of lots that are set at a precise width - say 50.00' - if the front or back line is not perpendicular to the side lines then the 50.00' frontage may calc out to 50.002', resulting in "gaining" a hundredth over a number of lots. He wasn't having it. At least he admitted it's not just me....

Very, very frustrating. I have maps in that jurisdiction where I've thrown an angle point into the sideline so that the individual parts will equal the whole. If you don't play the game your map gets stonewalled.

[CBarrett]

I've run into this issue on a number of subdivision maps in a jurisdiction that will remain nameless. On the latest map I'm working on, I received a letter, cc'd to my client, claiming I don't understand cogo. We talked in circles on the phone about it. I tried to explain to him that over a number of lots that are set at a precise width - say 50.00' - if the front or back line is not perpendicular to the side lines then the 50.00' frontage may calc out to 50.002', resulting in "gaining" a hundredth over a number of lots. He wasn't having it. At least he admitted it's not just me....

Very, very frustrating. I have maps in that jurisdiction where I've thrown an angle point into the sideline so that the individual parts will equal the whole. If you don't play the game your map gets stonewalled.

Is this a county surveyor or a mapchecker that did this, or a city surveyor? I would have escalated it till you find someone who understands math, and closure tolerances.

[Chiara]

Is this a county surveyor or a mapchecker that did this, or a city surveyor? I would have escalated it till you find someone who understands math, and closure tolerances.

He's a contracted City Surveyor with an LS number in the lower 5000s....