California Surveyors Forums

I have a disagreement of opinion with another Land Surveyor on the issue of monuments (once recorded, accepted and relied upon) found in the retracement effort of a prior Parcel Map. The scenerio is as follows:

A Parent Parcel Map is filed and recorded with monuments set on the exterior from that Map. Another Parcel Map is performed splitting this parcel in two. That surveyor, found the original monuments and they did not match the prior record Parcel Map courses, and so he held the courses from record and called the monuments found off by 0.1'-0.2' (along with an offset bearing). He then set his monuments on the division line of the new Parcel Map.

My take on this, is that the original monuments should have been held and the course dimensions would yield to the original monuments. That being said, in a retracement effort of one of the parcels of the later Parcel Map, in my opinion, I would conclude the Parent monuments to hold (along the exterior) from the original Parcel Map as opposed to a mathematically created geometry from the second Parcel Map. We found the monuments which were set from second Parcel Map to be off by as much as 0.1'-0.2' from our field measurements. I would intend to hold those as well, and show measured vs. record on the map.

The other surveyor's opinion is to generate a geometry (based on the second Parcel Map) and best fit it to a couple of the found monuments. This goes against everything I have known to be a legitimate procedure of survey practice.

I would appreciate your comments, and any supporting documentation to support your replies.

Thank you,

I am in agreement with you, obviously just based on the info you have provided.

I would hold any of the found original PM monuments and then hold the newer PM interior monuments as points on the new parcel line and then intersect into the original PM lines.

The recorded math is only a tool to lead a surveyor to where the monuments are. If you can prove there was a gross error or blunder then maybe you have a conversation about not holding something, but otherwise I would have a very difficult time doing what the other surveyor did.

I agree that the math is a tool to help find the pipe, but why is it I see so many filed maps finding original pipes, sometimes section corners or quarter corners and then calling them off 0.03' or maybe a few seconds in bearing. These are maps filed by surveyors that took the same test you and I did and some have the 4 year degree. Is their cogo better than mine? If you don't believe it go to Fresno and look at some of the newer tract maps.

Sorry to hijack the thread......just frustrated chasing seconds and hundredths.

Supporting documents...

Code of Civil Procedure
Section 2077
Two—When permanent and visible or ascertained boundaries or monuments are inconsistent with the measurement, either of lines, angles, or surfaces, the boundaries or monuments are paramount.

(Enacted 1872)

Brown - 3rd Edition, 5.12 - Order of Importance

etc.

I agree with you Michael. The other guy needs to learn that a retracement survey is not a geometry problem. The courses and distances are merely measurements or calculations made by the previous surveyor that you can follow to find the boundaries that were placed on the ground.

Depending upon circumstances, I would hold the monuments of the 1st PM for the exterior and the monuments of the 2nd PM to define the interior lot line, using the monuments of the 2nd similar to a closing corner.

But in most cases, 0.1' to 0.2' aren't differences that would cause problems of subsequent reliance and for many, if not most surveys, is within the positional errors of the surveys anyway. If that's the case, I would hold the monuments of both maps and just show my differences in measured B&D.

I appreciate your input and comments along with the support. I knew about the reference in Boundary Control and Legal Principles (almost by heart). Any other back-up reference would be great too.
I think one of the most ridiculous things I ever witnessed, was finding a large pipe monument with a redwood stake driven in it (Southern Calif.). It had two RCE tags and two LS tags in the wood stake, none of which were at the center of the pipe????

Michael,

I agree with your approach and reasoning.

I too have a disagreement going with similarities to yours, except even more egregious. There is still a chance that it will get worked out so I will not go into details for now.

I do not think these are isolated cases. I see a lot of maps showing found original monuments off for no other reason that 100 year old measurements do not fit between them, even Caltrans monumentation maps showing virtually every found monument off by a few hundredths or tenths this way or that.

We can only hope those who have held record data over monuments their whole career will read this and learn from it. The reputation of our profession hangs in the balance.

If they already filed a parcel map, then how is it that they are filing another parcel map. The monuments set per the first map are controlling monuments. There are some exceptions, but unless the other surveyor is claiming one of the exceptions then the monuments are absolutely controlling. The exceptions do not include small variations in measurements. A tenth or two is immaterial everywhere except in downtown LA, SF or SD.

Michael: I agree (I think)
To restate in my terms:
The Existing Boundary is an Opinion of the Surveyor. Right or wrong, it is simply an Opinion.
The New Lines are created as the Surveyor mapped and monumented them. His/Her location is hard and firm. Those are the "controlling corners" for the New Lines.

So... the first map expressed an Opinion of the Exterior but Established the New Lines
the second map expressed an Opinion of the existing lines but Established the new lines.

If either Surveyor goofed on the existing lines it is not important, but the New Lines are Gold... perhaps there are now a bunch of closing corners.

Hard to explain to the "paint by numbers" team ;-)

PS: I hate the use of the term Corner... owners want Lines!

so how big is this parcel, 9000 sq ft or 5ac. if this is a large parcel, were methods used that can prove an accuracy of 0.1'. I work with larger tracts of land, and I will never argue over 0.1'-0.2', because most client can not afford a survey with that level of accuracy over a larger tract of land. and on smaller parcel, did they have a closed loop, any redundant measurements? Show what you find, hold the monument.

Obviously the 2nd surveyor is perfect and in his opinion the original surveyor was sloppy.
Where do these guys come from and did they listen in boundary class.

Maybe we need a couple of dozen of these type questions on the multiple guess tests.

The whole basic idea behind the sectionalized land system was that measurements and not exact and that monuments hold over written bearings and/or distances.

I will probably do my normal here and tick some off, but my experience is that govt surveyors, whether moonlighting or not, think their measurements are better than any private surveyors. Either that or they get their jollies calling private surveyors monuments off.

I think you need to look at this further. A best fit line may in fact be the best answer. Here is why:

You have three monuments on a line. Of those three one is off by 0.1' when you hold the other two, doesn't matter which way til sunday you go. You try a best fit line and now all three monuments are off one way or another by 0.04'.

You run your adjustment (hopefully you are using some sort of least squares adjustment program like Star*Net) and you find that at One Sigma, the best you measured was 0.05' in both the Northing and Easting at any given point.

In my opinion, you are meeting the specs as to the best of your survey abilities and who is to say which of the two monuments are better than the others based on your residuals.

I would then in that instance use a best fit line solution. I would note on my record of survey as one of my boundary establishment notes that the line was established using a best fit line routine and that here are the offsets from the best fit line to each monument, I would also make a notation as to how good my measurements are by stating that the highest residual I have at One Sigma is 0.05' in the Northing, 0.05' in the Easting.

land butcher wrote:Obviously the 2nd surveyor is perfect and in his opinion the original surveyor was sloppy.

I will probably do my normal here and tick some off, but my experience is that govt surveyors, whether moonlighting or not, think their measurements are better than any private surveyors. Either that or they get their jollies calling private surveyors monuments off.

From my perspective (20+ years private, 12+ year gov't), there are plenty of extreme (mathematician button pusher) examples in both sectors. I can reasonably assume that, in conducting most 'common' or standard (excluding the high order accuracy type) boundary surveys, that you will rarely arrive at an exact position from day to day, let alone between morning and evening. And with GPS (do these 'perfect' measurers even watch the HDOP/VDOP?), my gawd, it's potentially even worse!

Unless a surveyor is accounting for and doing their best in eliminating all potential sources of error (setups, equipment calibrations, atmospheric/climate calibrations, etc.), the surveyor is never going to be able to repeat EXACT results. Passed three decimal places is only doable in the 'cad' world of your PC.

I have seen surveyors call 0.0x's in differences between measured versus record ... in 1/8th and 1/4 mile lines ... and I just laugh, because frankly, they are either egomaniacs (aka pincushion syndrome abettors) or they are just 'button pushers' who live by math with extreme prejudice. I'd really like to see these 'surveyors' set all of their error correction routines in their equipment to ZERO and then watch their heads explode when they can NEVER get 'perfect' results.

In a non-high order accuracy boundary survey, if one can consistently hit the same rebar (5/8" or 0.05') or even a cap (1" or 0.08') from day to day, then they're doing pretty dayum good in itself. Some may call that sloppy, but I seriously doubt any of those 'perfectionists' set their rebar/caps EXACTLY where they calculated them to be. And if they attempted it, (ever see anyone continuously beat the rod around to get a perfect reading?) I doubt they accounted for and eliminated all potential error during the process.

Set it, check it: if you can repeatedly 'hit' the rebar and/or cap, move on and call it good!

David, well said. And unfortunately, it will need to be said again and again. Sources of error and measurement accuracy still seems to be poorly understood, even be many veteran surveyors. I agree it's not about "sloppy", it's about realistic expectations and experience. And the willingness to say, "I can't measure perfectly, and never will be able to".

Dave Ryan,
Humboldt County