Deriving record bearings and distances from GLO Plat

Scott · Post by **Scott** » Thu Mar 12, 2009 6:58 am

Can anybody offer me suggestions for deriving bearings and distances for sections 27, 28, 33, & 34 on the attached GLO Plat. The south line of the township is the baseline. In other words this is T.1 N.
Thanks,

VANCE · Post by **VANCE** » Thu Mar 12, 2009 7:17 am

What do the GLO field notes say?

RAM · Post by **RAM** » Thu Mar 12, 2009 7:25 am

Without looking at the plat I can say you need the notes. The plat is dependant on the notes.

Scott · Post by **Scott** » Thu Mar 12, 2009 8:46 am

Ok, thanks, that is what I figured.
<casurveyrecords@ca.blm.gov>
FYI, email here with T,R,&Sec and for $1.10/sheet they wil snailmail them to you.
John Patton (916.978.4330) is a contact there also.

Ric7308 · Post by **Ric7308** » Thu Mar 12, 2009 9:13 am

John's great. Helped me out a number of times.

VANCE · Post by **VANCE** » Thu Mar 12, 2009 9:57 am

Me too, just need to wait about a week, but he does a great job.

dmi · Post by **dmi** » Fri Mar 13, 2009 3:21 pm

you need to make sure you get all the plats, and finally the official plat. there could be more than one. The attachment you have indicates 80 chains and cardinal for the undimensioned lines, but this plat looks funny.....Is this a S&W plat?

E_Page · Post by **E_Page** » Fri Mar 13, 2009 4:24 pm

John helped me out as well. In my case, it turned out that it was cheaper to ask for a whole microfiche sheet than it was to get just a few pages on paper.

goodgps · Post by **goodgps** » Fri Mar 13, 2009 10:29 pm

Scott,
The distances seem pretty clear as are shown on the plat. If a distance is missing, it may simply be a "ditto" of the section adjacent. most likely 80 ch.
The others are listed on the map i.e. 80.14 etc.
As for the bearings, the sections were meant to be laid out north and south.
Seldom the notes will state a bearing other than "thence on a true line" . . .
etc. to get an approximate of what the original surveyor may have measured, you can assume north on a range line and break down the township using the distances shown on the plat.
If you're trying for precalcs to do a retracement AND there is no other record map info available, forget it.
You'll want the notes to identify topo calls as the government surveyor traversed his way, then find them during a field survey. [I'm speaking in terms that this is hill land and not flat farm land or out on the islands]

Good luck with the survey !! sounds interesting !!

Gromatici · Post by **Gromatici** » Sat Mar 14, 2009 10:51 pm

If you plug in the record you'll find it won't close by several dozen feet if not more. You could just use cardinal. I generally use the assessor's GIS to put into my garmin or a more recent survey. Then I look in a 100' radius while I hold a copy of the notes with me (don't take the "original" copies!).

Note sure why you told us to email John, but if your doing a survey of the PLSS you need the plats and notes. The notes will give you bearing trees and other callls that you should use first before resorting to proportion.

Ric7308 · Post by **Ric7308** » Sun Mar 15, 2009 8:34 am

Eric,

I believe Scott was just passing on John Patton's contact info to everyone. If you haven't met or talked with him, more times than not, he is the person that will research the plats and notes for copies for you.

Ric

Gromatici · Post by **Gromatici** » Sun Mar 15, 2009 7:51 pm

O, I see. Sorry. I thought he was asking a question and then when he directed us to Jon (whom I've used on numerous projects) I was confused.

Thanks,

Scott · Post by **Scott** » Mon Mar 16, 2009 7:46 am

I know I need to get the notes, and I will if/when I actually get the job. In my experience the notes don't shed a whole lot light on the bearings run. I wanted to know if anybody has any insight to the variance degrees and minutes shown on a whole bunch of the lines of the plat, as if they are bearings. Usually they show one magnetic variance on the southeast corner of the township. This one has it like bearings on most of the lines of the plat. What does that mean? Is that the magnetic variance for each line labeled? If so, then how does that work?
I do realize that the notes will help with distances run and corrections.

RAM · Post by **RAM** » Mon Mar 16, 2009 12:03 pm

Good.

Be careful, the bearings are always in the notes, that is official record. You methoed above could create problems. Yes the section may not close, but should meet the standard at the time of the survey. The notes will also have the basis of bearings for the survey and where it was established. sometimes can be hard to read but over all good stuff.

RAM · Post by **RAM** » Mon Mar 16, 2009 12:04 pm

PS,

Precalc of GLO notes does work to search for corners.

dmi · Post by **dmi** » Mon Mar 16, 2009 12:19 pm

North is based upon astromonic north. Everything relates to the true merdian.
The variation is shown for people using a compass. Variation is the difference between the magnetic north of the compass and astronomic north. Prior to 1894, contract surveyors could subdivide the sections using a compass. That practice was banned. You might use a compass bearing to search for corners of the early surveys where a compass was used to subdivide the sections.

Subdivision of sections were run on lines parallel with the east line of the township,in theory. So, it is a good idea to get the notes and plats for the running of the township. In the townnship notes you will find the method they used to establish north. Because of convergence, a line parallel west of the township line could vary from the direction of the township line by a few minutes,depending upon latitude. This difference is shown on the plat.

I remember being told....

to consider what the original surveyors were told to do
what they reported they did
and what they actually did might not be the same thing....

7702 · Post by **7702** » Mon Mar 16, 2009 12:50 pm

I've witnessed what can happen when cadastral surveys are performed without the proper care that they require. It's not pretty.

Here's the Board's view on the importance of the matter:

PLS Act Licensure requirements:

"The applicant shall be thoroughly familiar with (1) the procedure and rules governing the survey of public lands as set forth in â€œManual of Surveying Instructions,â€ published by the Bureau of Land Management, Department of the Interior, Washington, D.C.,....."

Board Rules:

415. Practice Within Area of Competence.

"A professional engineer or land surveyor licensed under the Code shall practice and perform engineering or land surveying work only in the field or fields in which he/she is by education and/or experience fully competent and proficient."

I would hope that anyone who doesn't feel that they are "fully competent and proficient" would acquire the needed training and/or experience before taking on a such a project. And there is no substitute for experience when it comes to retracing surveys and searching for original GLO evidence.

Surveyor826 · Post by **Surveyor826** » Tue Mar 17, 2009 11:27 am

Scott, in #13 you asked about the variations shown on the plat.
The 1850/1855 instructions/manual set that out on pages 17-18 under:
"SUMMARY OF OBJECTS AND DATA REQUIRED TO BE NOTED"
"19. The variation of the needle must be noted at all points or places on the lines where there is found any material change in variation, and the position of such points must be perfectly identified in the notes."

You really need the field notes to see how the survey was performed, and it should then become clear when, where, how, and why you might apply those variations.

All the Best,

goodgps · Post by **goodgps** » Tue Mar 17, 2009 12:18 pm

I was wondering how many of the actual original notes to these surveys, were lost in the 1906 earthquake. ??

I've also seen quite a variation of "completeness" of gov field notes.

Sometimes the "Surveyor" wrote the notes, then suddenly, it becomes apparant that someone else is doing the scrivening. Watch for nautical terms on some notes, such as "undulating hills" Often times, instrumentmen were sailors on shore leave.
Also the variation can be computed directly in the field, by solar observation or a nightime polaris reading, then simply place the compass on the line to observe the needle variation.
[Davies new Surveying] A.S.Barnes & Company,1873.

For hill area retracements, tis far better to carry the notes, for the station calls, a compass, your GPS and anti-poision oak spray. Poision oak tends to like the old rock mounds.
And like a bunch have said. . . search in a 100-foot radius.
For these types of retracement, common sense and observation weigh better than the law books.

7702 · Post by **7702** » Tue Mar 17, 2009 12:45 pm

Due to changes in the earth's magnetic field that occur over time, if you were to carefully determine the magnetic variation (declination) at those locations today, you would likely note a "material change" in the variation from what was recorded on the plat or in the notes.

NOAA's "National Geophysics Data Center" has on-line modeling programs that you can use to compute "estimated" variations in the magnetic field for a specific location and date. Sort of like the NGS's HTDP program, except crustal magnetic fields are monitored instead of crustal motion. I think the USGS's National Geomagnetism Program has similiar magnetic field models as well. Just what every surveyor needs in their arsenal.

If I'm doing any field searches with a compass, If possible, I prefer to calibrate my compass using found monuments of record.

7702 · Post by **7702** » Tue Mar 17, 2009 12:53 pm

Depending on how confident you are in your predecessor's work, you may need to increase that 100' search radius a bit (retracing some of the Benson Syndicate work comes to mind).

Scott · Post by **Scott** » Mon Mar 23, 2009 3:04 pm

out there who would like to team up with me on the GLO portion of this project? One section corner has not been found or searched for since it was set in the 1860's. There might be 2 more that need to be set of varying age of last seen. I would like to find somebody that would take me in the field with them so I can get the experience and have me do any additional research with direction. Yea, I know when the client is with you it costs more (ha ha). Right now I am just looking for a price/estimate for the finding or replacing as needed of the section corners (1 to 3). I've done some research and can enlighten anyone qualified who is interested. And no I still haven't got the notes and probably won't unless I get the job for sure.
Thanks everybody for your posts on this subject.

Surveyor826 · Post by **Surveyor826** » Mon Mar 23, 2009 4:23 pm

There is so much that someone with local experience can help you with, and tune you into when searching. Maybe tell you something like "Oh, that's a survey by deputy Richardson, you can always count on his data".
Or the opposite.
You realize you're gonna have to have those notes prior to your search, right?
All the Best,

7702 · Post by **7702** » Mon Mar 23, 2009 9:10 pm

Scott,

Can you tell us which corners are in and which ones are reportedly missing or of uncertain status?

Scott · Post by **Scott** » Tue Mar 24, 2009 7:16 am

I know I need the notes to do the survey. I will get the notes to do the survey. Right now I'm trying to get a proposal and price together for my client.
As far as public posting any information, I don't know how sensitive the project is and don't want to jepordize my clients' interest in the property. If you are interested and qualified contact me and we will talk. An SOQ with some examples of your previous work in the PLSS, showing finding original corners and setting a missing corner (or 2) by double proportionate measure would be something I would want to see. I will be gone Wed-Sun and will check back on Monday.
Again, thanks everybody and please for the last time: I know I need the notes to do the survey. I will get the notes to do the survey.

California Surveyors Forums

Deriving record bearings and distances from GLO Plat

Deriving record bearings and distances from GLO Plat

Retracement

OH

I am asking a question.

Noting Variations per old manuals

Original notes

Are there any GLO experts

I would suggest a qualified LOCAL expert