Traverse Question

Tom,
IMOA you cannot run back on the same points. You have to occupy (set up on) the monument you are tying and turn angle from it on the way back out. But you can save a lot of time by placing the "on the way out" points within a few feet of the "way in" points and not have to brush. Just be sure and put numbers on the flagging on the points so you do not get confused with back sights and such. With only 3 or 4 points you should be fine.
Scott

I would be tempted to run an alternate point traverse down one cut line and traverse through the monument in question. Don't know of any data collectors that support this method so all measurements would be booked and manually calcd. Just one approach to consider...

> In order to close out this traverse, would you run back from the monument by setting different points (lots of time cutting) or could/would you run back on the same points using different point numbers?

Well, if you're ultimately interested in knowing (a) what the relative positional accuracy of the monument at the end of the traverse is and (b) demonstrating that your measurements are reliable, why can't you accomplish that by redundant measurements on the same traverse line? If you're using forced centering, the centering errors on the traverse stations should be nearly zero.

If you want to be really, really careful, you can survey back along the same line with new setups on the same control points, but it shouldn't be necessary. Naturally, computing the positional accuracy of the monument will require least squares survey adjustment software like Star*Net.

if you are using any kind of least squares, set up between the points and do some close-to-180-degree free stationing.

Gets you about the same thing as the forced centering but better because it leaves out the tribrach error at the instrument. Also gives you different angles & distances. FWIW.

I'd run back through the same traverse monuments. I don't see anything to be gained with a second set of monuments.

1. Does your state have a trespass law? Mass. has a beautiful one: provided I provide notice to the neighbor, I am allowed to legally trespass to complete my work. Most people are happy to receive my certified letter with this reference, some are not.

Section 120C of Chapter 266 of the MGL reads as follows:
Whenever a land surveyor registered under chapter one hundred and twelve deems it reasonably necessary to enter upon adjoining lands to make surveys of any description included under “Practice of land surveying”, as defined in section eighty-one D of said chapter one hundred and twelve, for any private person, excluding any public authority, public utility or railroad, the land surveyor or his authorized agents or employees may, after reasonable notice, enter upon lands, waters and premises, not including buildings, in the commonwealth, within a reasonable distance from the property line of the land being surveyed, and such entry shall not be deemed a trespass. Nothing in this act shall relieve a land surveyor of liability for damage caused by entry to adjoining property, by himself or his agents or employees.

2. Have you ever seen a mine route survey? You reoccupy every other point so your traverse looks like a series of diamonds. Having never performed one, I have no idea how well it works, I just recall seeing the diagram and thinking: huh, that's pretty neat.

3. How are the other neighbors around the monument?

A method I've used and seen used by others is to run 2 parallel traverses down the same cut line. Set 2 points a couple of feet apart at each setup location. One point for each traverse. Basically you run 2 traverses side by side in the same direction.

Benefit is that it saves quite a bit of time. You make 2 setups at each "move up" and you end up with two, truly independent traverses.

The biggest thing is to have a good procedure in identifying which points go to which setup so you don't mix up foresights or backsights.

> 1. Does your state have a trespass law?
Oregon has a right of entry law but if the landowner objected, and I had any reasonable alternative open to me, I'd avoid traversing across the objecting landowners property. Right of Entry complaints are a very common way to end up in front of the state board.

State of California has similar law per the Land Surveyor's Act:

8774. Right of entry
(a) The right of entry upon or to real property to investigate and utilize boundary
evidence, and to perform surveys, is a right of persons legally authorized to practice land
surveying, and it is the responsibility of the owner or tenant who owns or controls property to
provide reasonable access without undue delay. The right of entry is not contingent upon the
provision of prior notice to the owner or tenant. However, the owner or tenant shall be notified of
the proposed time of entry where practicable.

> State of California has similar law per the Land Surveyor's Act:
>
> 8774. Right of entry
> (a) The right of entry upon or to real property to investigate and utilize boundary
> evidence, and to perform surveys, is a right of persons legally authorized to practice land
> surveying, and it is the responsibility of the owner or tenant who owns or controls property to
> provide reasonable access without undue delay. The right of entry is not contingent upon the
> provision of prior notice to the owner or tenant. However, the owner or tenant shall be notified of
> the proposed time of entry where practicable.

Don't forget Penal Code 602.8 & Civil Code 846.5. Those 2 CA laws catch a deputy's ear better when responding to a report of trespass by a disgruntled landowner.

:good: It's the measurements, not the intermediate points, that count.

If you have to do a closed traverse, give the intermediate points new numbers on the way back.

If you use least squares, use the same point numbers both ways - that tells the LS algorithm that there is zero distance between the points that you know are the same ones. With different point numbers you are throwing away that valuable information.

I would run a loop, close to the run out, running back I would not cross that first run out. Holdover from the days of doing by hand and checking internal angles, still a good thing to watch for.
jud

^^^^^

THIS

Yes!

Our crew shoots every backsight check with a new point number.
I spend an odious inordinate amount of time figuring out which point numbers are which so I can milk the fieldwork for redundancy.

Wish I could get this across to them. Not gonna happen until they start reducing their own notes, I guess.

surprisingly enough, you can still add up the angles when your traverse crosses itself. You have to pay a lot more attention, though, to how you add them.

:good:

:good: :good:

as Mr McLain is from Traverse City... I would follow his advice!
😛

Gee I miss cutting line...no wait, no I don't, lost my head there for a second.