I joined the forum as I enjoy creeping around and following some threads here even though I do not understand half of what is going on. I have a very basic question here in regards to the GLO PLSS system. We are located in Montana and many times we have to identify a rough idea of property line, mostly section lines on industrial timber lands.
Now our education only provided us with basic map and compass skills. I know enough though when checking these lines to look at the platts in the county and see if there are angle breaks etc. Corners are almost always in place and many times the 1/4 corners can be found.
My question being; the platts show a true meridian arrow and a declination of 8 degrees E. And the section lines many times may show a N09W' to the 1/4 corner followed by maybe a N04E. On my compass is all this built off of a true north? I know they have those assumed north lines between 2 points they used with the Township/Ranges that were many times off of true north.
What I am getting at is that I have one side of a section with corners in but no obvious blaze line and I can't seem to run the bearing. I maybe can come within 100' or so. The bearings on the platt.......are they built on true north on my compass. DO the 8 degrees of declination mean anything if I am using the current 13 degrees today? Or did the use some other version of north?
Yes I am a layperson here. But it is not economically feasible to have these lines surveyed again as we are just picking the scraps of timber left. We also normally just find the old corners and blazed line and then put a large buffer on this. But I've been researching the PLSS a bit and I think the universities teach us our map skills on way to of a basic level.
Any help on how I find north and whether I factor in the old declination or anything else would be much appreciated for these section lines.
Howdy Jerry, glad you joined
Compass surveying at best is hit and miss depending upon your compass, skill, experience, understanding, source of bearing and luck.
Most people that run by compass do not actually hit the place they intent to on the other end of the line, they get close.
Then they adjust their run accordingly to straighten their markings of the line.
NOAA Magnetic Field Calculator
is a good starting place to understand the effects and use of declination.
😉
Hiring a surveyor is not optional. Surveying is a regulated profession. Surveying by anyone other than a land surveyor is considered unlicensed practice.
If you can imagine hospitals putting anyone in a white smock and a stethoscope to save money on the exorbitant salaries of medical doctors then by all means do your own surveying and assume the full responsibility.
There are many cases each year of land owners suing for damages caused by a forester incorrectly interpreting a boundary line. The cost of the damages is ironically appraised by a forester after a land surveyor determines the boundary. Each stump is appraised at three times the value of the timber and charges of criminal trespass are adjudicated.
Sometimes it helps to attempt to imagine that you are watching the survey crew that laid out the sections line in your area. In my home county that would have been in 1865. Ask yourself, "How did they know where NORTH was?" The next question is:" So how did they know there was a declination to report?"
Jerry - I graduated from the U of Montana a long time ago and at that time there were surveying, advanced surveying, photogrammetry classes and spring semester at Lubrecht to hone the field skills in surveying, the GLO, maps and compass use and various other skills for the woods for the Forestry students. I know for a fact that ALL of those classes have been dropped, at least at UM and you get some rudimentary trainings. That being said, you are risking timber trespass every time you try to get near, what you believe to be a boundary line. Plum Creek learned their lesson about 10 years ago from going to court a few times and did stop their foresters from running boundary lines. They were hiring out to local surveyors to run any lines that were up against private, state, tribal and federal land. They began phasing back on that about 5 or 6 years ago until they sold out again last year.
The GLO was running true bearings; so an adjustment using the current declination is what you would be using. Good luck and hopefully you don't end up in court for timber trespass.
Bearings on the map should be true.
Adjust your compass declination to the current value...
http://www.ngdc.noaa.gov/geomag-web/calculators/mobileDeclination
Use the current value, the quad maps are way off.
You could be experiencing local attraction too, 100' is an indication of that. Very dangerous to mark line in an area of local attraction, you could be way off.
Bearings are of less interest to surveyors than the angles between them are. So pay particular attention to the basis of bearings statement. It may be that the bearings in your case are based on - not much.
If you are finding all the PLSS corners in a logged area it is almost certainly because some surveyor has recently restored them. It may be that surveyor has provided a map with state plane grid bearings, which, depending on the location on the grid, can vary from astronomic bearings by 2å¡+/-.
There can be local attraction of the compass. It's just not a very precise way to run a particular bearing. The main thing is, if you have monuments at either end of your line, run whatever bearing it takes to start at one and end up at the other. In the GLO field notes it was called running the line "random and true".
The GLO ended reliance on the compass to run bearings in the late 1800's. They were all about getting it done cheap and fast - precision wasn't real high on their priority list. But the compass just wasn't getting it done.
Thanks everyone,
I knew it was risky to post this on a surveyors forum. I do know for a fact that Plum Creek, MT DNRC, and private consultant foresters all "run section lines". Yes in theory we should always have it surveyed but the reality is this does not happen at least if corners are in and there is a blazed line. Now on a line in virgin timber yes people would have it surveyed. But for most of these parcels there is a historical cut line/buffer line where cutting has occurred on both sides of the lines over the years.
But.....back to my basic question on the bearings. Why many times, when standing at a corner and shooting the bearing off the plat map does it not coincide with the GLO/BLM blazed/placarded line. Normally it is close but not perfect, I'm not talking inches here but many times 10-20 foot difference on a shorter field of view.. If the plat has a north meridian and declination stated then they were going "true north" and all a person would have to do is set current declination and follow the stated bearing on the plat? Am I doing something else incorrect. Do I need to do anything with their declination at the time.
Again I did not want to turn this into a lecture on hiring a surveyor. All the foresters I know both agency and private use a combination of platt map, compass bearing, corner pins, aerial photo from MT cadastral or ARC GIS, old blaze lines, timber volume along lines, and knowledge of landowners on all sides of the lines when making a determination if they want that parcel surveyed or if they are comfortable enough to have a 200 foot buffer against the probable boundary.
I guess my other question is that my understanding is that old section corners and "historical lines" are considered to be the property boundary on section lines? Is this actually correct or is that heresay?
It may help to know we don't use a declinated compass, for much more than witness trees. Unless, there is alot of manetic disturbance, and we WANT to map that. It's alot of work.
Essentially, you are asking a group of surveyors, how to read a declination note, so you can go surveying, on the right bearing!
Here you go.
Go find the CORRECT endpoints of the line in question. Set up your compass, and set what you think is the right declination. When you have run across that section, you'll have an error. Now, you compute the modified declination, and apply it, now you are set up for that line. It will NOT apply to other sections. NOW you can go to work!
Another factor... You can go to the compass store, and out of 10 compasses, 3 will be 1/4 degree different from the rest...
And one might be 1/2 degree different...
So... Now you want to know the "proper declination".
Declination varies by time. It changes over the years... It changes by a few minutes, morning, to night.
And, you come hopping along, and ask a bunch of surveyors, "how do I do this?"
And somebody says hire a surveyor...
Don't be offended. Learn what your question means. When it falls into our ears, it means something different, than when it falls on your tongue... Er... Keyboard!
I honest don't mean to rebuff you.
I am saying it's simply a more complex question, than a brief answer you are seeking.
Just saying "there's more to it than that".
Nate
Consider the accuracy of compass sightings plus local attraction in the area including the surveyor's part.
Jerry Fallon, post: 370162, member: 11650 wrote: I guess my other question is that my understanding is that old section corners and "historical lines" are considered to be the property boundary on section lines? Is this actually correct or is that heresay?
The line as defined by the original monuments on the ground is the boundary. Not the line as defined by a bearing on a map.
Using a compass to retrace lines is a total crapshoot. No other way to put it. There myriad unseen magnetic disturbances around the user from the hammer in your vest to the rocks under your feet that will affect the needle's direction, sometimes dramatically.
This discussion is good; brings to light why surveyors need to be licensed.
There is no straight answer to your simple question.
If you actually want to know.... Become a surveyor... Guess what? The number one advice for surveyors, who just got theit ticket is:
Now, your education is beginning!
Licensed surveyors disagree with each other.
You walk into the room, and ask "for a simple answer".
To most every question about surveying, there are 500 answers, and only 10 of them are starting to "get close enough".
"How much accuracy can you afford?" is another saying.
When standing on the moon, you point at earth, and say: "that's where I live"
When standing in your yard, you can point at your house, and say: "That's where I live".
They are both true statements, but one is more accurate. Relativity.
Have fun!
I'm persuaded that curiosity keeps more of us in this game, than money.
Nate
Jerry Fallon, post: 370162, member: 11650 wrote: Thanks everyone,
I knew it was risky to post this on a surveyors forum. I do know for a fact that Plum Creek, MT DNRC, and private consultant foresters all "run section lines". Yes in theory we should always have it surveyed but the reality is this does not happen at least if corners are in and there is a blazed line. Now on a line in virgin timber yes people would have it surveyed. But for most of these parcels there is a historical cut line/buffer line where cutting has occurred on both sides of the lines over the years.
But.....back to my basic question on the bearings. Why many times, when standing at a corner and shooting the bearing off the plat map does it not coincide with the GLO/BLM blazed/placarded line. Normally it is close but not perfect, I'm not talking inches here but many times 10-20 foot difference on a shorter field of view.. If the plat has a north meridian and declination stated then they were going "true north" and all a person would have to do is set current declination and follow the stated bearing on the plat? Am I doing something else incorrect. Do I need to do anything with their declination at the time.
Again I did not want to turn this into a lecture on hiring a surveyor. All the foresters I know both agency and private use a combination of platt map, compass bearing, corner pins, aerial photo from MT cadastral or ARC GIS, old blaze lines, timber volume along lines, and knowledge of landowners on all sides of the lines when making a determination if they want that parcel surveyed or if they are comfortable enough to have a 200 foot buffer against the probable boundary.
I guess my other question is that my understanding is that old section corners and "historical lines" are considered to be the property boundary on section lines? Is this actually correct or is that heresay?
Don't setup your compass on the monument, they often have a magnet under a cap or they are iron which attracts the needle. Get as far away as you can and work your way on to the line.
Pocket compasses are okay for following existing line but if you are running line between existing monuments you need a staff compass.
Generally, the physical monuments control course and distance but not always.
There is overlap between professions. There is not a bright line line not to cross but be careful. If there are no monuments then a Surveyor should be involved. If the line is monumented and the owners consent, Foresters can flag the line.
Jerry Fallon, post: 370162, member: 11650 wrote: Thanks everyone,
I knew it was risky to post this on a surveyors forum. I do know for a fact that Plum Creek, MT DNRC, and private consultant foresters all "run section lines". Yes in theory we should always have it surveyed but the reality is this does not happen at least if corners are in and there is a blazed line. Now on a line in virgin timber yes people would have it surveyed. But for most of these parcels there is a historical cut line/buffer line where cutting has occurred on both sides of the lines over the years.
But.....back to my basic question on the bearings. Why many times, when standing at a corner and shooting the bearing off the plat map does it not coincide with the GLO/BLM blazed/placarded line. Normally it is close but not perfect, I'm not talking inches here but many times 10-20 foot difference on a shorter field of view.. If the plat has a north meridian and declination stated then they were going "true north" and all a person would have to do is set current declination and follow the stated bearing on the plat? Am I doing something else incorrect. Do I need to do anything with their declination at the time.
Again I did not want to turn this into a lecture on hiring a surveyor. All the foresters I know both agency and private use a combination of platt map, compass bearing, corner pins, aerial photo from MT cadastral or ARC GIS, old blaze lines, timber volume along lines, and knowledge of landowners on all sides of the lines when making a determination if they want that parcel surveyed or if they are comfortable enough to have a 200 foot buffer against the probable boundary.
I guess my other question is that my understanding is that old section corners and "historical lines" are considered to be the property boundary on section lines? Is this actually correct or is that heresay?
Have you ever been 900' off? My forester was once, but he was excellent forester.
Duane Frymire, post: 370196, member: 110 wrote: Have you ever been 900' off? My forester was once, but he was excellent forester.
We had a Forester off 200 to 300' because he used a Walmart GPS in heavy Redwood forest. His first flag from the monument at the west end was 30 degrees off bearing and there is no evidence he found the monument on the east end.
Another way to look at this, is to get a quad sheet, and place it on a drafting board, and use a parallel bar, to just take a look at the section lines. They were run by compass. They would set their compass up, (Jacobs Staff) Rittenhouse design, and point it at the north star, when it became viseable. Set their declination. And, they would do this occasionally. To "Correct it up".
I believe the parallel bar exercise to be useful in retracement. You can spot patterns. Like, where declination changes were made, etc.
N
Section lines are not necessarily property lines, they might be.
🙂
