A little heads up on using the topographic maps to scale from.
Fourty Five years ago I started out in the mapping profession with the U. S Army. I was a Cartographic Drafter and hand engraved the sheets that make up those maps.
They are VERY accurate in production. Our line widths could not be off by 0.001" or we had to re-engrave the sheet.
Such a map produced on a stable 7 mill mylar base would be very accurate and useable for your needs. A paper copy is an entirely different matter.
On a 15 Minute Quadrangle, the expansion and contraction of the map due to heat and humidity (or the lack thereof) can be significant. That's why most surveyors use then only for planning tools.
Using a resection with only angles is a semi-hard computation, and note on the link provided it even says that it is very inaccurate. It isn't that it shouldn't be done per se, but that you need to know what you are getting and its level of precision. Adding to the fact that the method isn't extremely accurate, that your control points aren't all that accurate anyway, it makes it worse.
The more "known" points you can turn to the more redundancy you have in calculating your position. Redundancy is your friend. If you turn, to, say, seven different "known positions" you can possibly throw out outliers and you can also see what kind of error circles you are getting based on how much different each calculation is. The "outlier" would be one that is extremely out from all the rest. (Say you get 7 locations, and most are all within around 20' from each other, but all the angles associated with one of the points produces a location that is is 100' out, that would be the outlier.)
Perhaps it would be better to ask some of them if they are willing to share the secrets of the trade than to deal with the 3-points resurection problem and do lots of calculations on the fields.
Honestly, you can't do what you want to do, the accuracy isn't there.
What probably happens there like here is the surveyors look for the old monuments marking the fields and then if they don't find the ones marking your field they expand outward looking along the roads until they do find enough to recreate your position by measurement, "backing" in your property, hopefully from both directions and hopefully they match well to the "record". That's my guess anyway, not being a surveyor there you can take it for what it's worth which isn't much.
I will say this, once you do have markers, make something so visible and sturdy that even a plow will have an issue with disturbing it.
As you now see that will be worth the trouble, the same thing happens here with monuments near hay meadows, wheat fields, anything that gets plowed.
English
I gotta tell ya. Surveying equations, solutions and property rights aside. I have to compliment you on your mastery of the English Language. Learning another language is difficult enough without introducing technical terms of a particular discipline. Kudos.
"last resort solution"
Not only that, but for some configurations of reference points and position of the observer, there is no solution to a 3-point resection.
In other words, "Sometimes you just can't get there from here".
Better to hire a competent surveyor where ever you are.
3 point resection, a crap load of paper, 4 or 5 number 2 pencils and a helluva lot of time.
> 3 point resection, a crap load of paper, 4 or 5 number 2 pencils and a helluva lot of time.
[sarcasm]But he's a Serbian Electrical Engineer... Surveying Calculations will be a piece of cake for him. [/sarcasm]
Carl
> > 3 point resection, a crap load of paper, 4 or 5 number 2 pencils and a helluva lot of time.
>
> [sarcasm]But he's a Serbian Electrical Engineer... Surveying Calculations will be a piece of cake for him. [/sarcasm]
Then he should also have plenty of paper and pencils also. 🙂
"last resort solution"
As several have previously mentioned topographic maps lack the accuracy you need. Also the geometry of the reference points (your A B and C) must be carefully selected. The best solution for your "X" will be if you are at the center of an equilateral triangle. Since you are dealing with 4 corners they can not be at the center of one triangle.
Depending on the quality and adjustment of your instrument and the size of your triangle the calculated point "X" could move a few meters or tens of meters each time you try.
Also remember any time you attempt to survey your own property line you are also surveying the line common to your neighbor(s). Surveying is more than measuring it is also understanding the property laws and legal history of your area. In most parts of the world surveying property requires a professional license. That also means attempting to survey without a proper license is usually a violation of the local laws. Setting a corner in error and/or violating the law may create more problems than you already have. Attorneys fees, court costs, fines and damages paid to neighbors can quickly exceed the the cost of a survey. Additionally a survey will likely be required to gather evidence for the court to examine.
The best advice I can give you is consult with a local professional surveyor for an estimate of the cost to survey and monument your property. This could also include setting points in the roads between the fields to recover the actual corners. Also ask what your local laws allow you to do yourself. Then try to get your neighbors to share in the cost. It may save all of you time and expense in the end.
Just got back in to town and find this diatribe. Amazing to say the least, some of the comments.
I assume you do own a hand held GPS.
1) How accurate does this location need to be? Plus or minus 30 ft in any direction, use google or a quad map. Contrarily, set a way point for all your "known" points, and then fudge your own resection by staking out to each of them. Takes time, but it works if you do it right.
2) Is elevation a concern? I don't think so from what I read, but if it is..... your hand held GPS will get you within 20 ft or so. If you don't have a hand held, go buy one (($100 all day long just about anywhere for the cheapy, which does yield the same accuracy as the $400 ones but without the buzzers & whistles).
3) Are there any adjoiners involved with your project? Perhaps you could share costs.
4) Are you anywhere near a property line? If so - call a surveyor.
5) I assume there are no permits involved, but if so have you checked with your local authority? Often times they can be an ally, believe it or not.
Good luck Farmer "Begginer". Some spell check may be in order too.
> Good luck Farmer "Begginer". Some spell check may be in order too.
Wayne, please answer in Serbian, so the person you are adressing doesn't misunderstand any of your text.
Geez, man, lighten up.
Yeah, and to think I got excoriated about maybe going to flag up a feller's pins so he could see them. He already had it surveyed a month earlier and knew where the pins were. The surveyor just didn't flag them up like he wanted. Nothing more. I wasn't re-tracing or establishing or verifying. I got blasted for pushing a fine line and others out-right chewed me out in public and many more in private.
Personally, I find it a little hypocritical that this person hasn't been blasted for even thinking of practicing licensed survey work without a license.
Guess I'm a still a little bitter about that. I take personal attacks serious and such .. well personal. I never did the job.
Note to self: Let it go Big E! 🙂
> Yeah, and to think I got excoriated about maybe going to flag up a feller's pins so he could see them. He already had it surveyed a month earlier and knew where the pins were. The surveyor just didn't flag them up like he wanted. Nothing more. I wasn't re-tracing or establishing or verifying. I got blasted for pushing a fine line and others out-right chewed me out in public and many more in private.
> Personally, I find it a little hypocritical that this person hasn't been blasted for even thinking of practicing licensed survey work without a license.
>
> Guess I'm a still a little bitter about that. I take personal attacks serious and such .. well personal. I never did the job.
>
> Note to self: Let it go Big E! 🙂
That's why I started off with the "asbestos undies" comment... I didn't flame him, I just warned him it might be coming...
Oh well...
Use Least Squares program for resection
A least squares program is a quick way to do resection. No need to fight with a bunch of complicated formulas when you have a tool already that will do it. You can get an answer, just no statistics, if you don't have redundancy. If your program refuses to work without redundancy, just copy one of the measurements as a duplicate and ignore the (now invalid) statistics.
> Personally, I find it a little hypocritical that this person hasn't been blasted for even thinking of practicing licensed survey work without a license.
Other than the one guy that posted pictures from Serbia a few weeks ago, I doubt there is anyone here that is well enough versed in the the Serbian cadastre to voice an opinion one way or another.
The amount of work that has been done over the last twenty years to rebuild the land tenure systems in Eastern Europe is mind boggling.
1) I need less than 3 inches accuracy. So hand held GPS won't do.
2) No. The terrain is flat and all is in one plain.
3) No. Just me.
4) I am exactly at the property line 🙂
5) No, no permits involved.
I haven't even noticed I misspelled that. I guess I am still a begiNNer at english spelling 🙂
Good thing nobody noticed I wrote "resurection" instead of resection in one of my posts 🙂
Of course they are not a piece of cake. I tried it and I agree with Kris. Hard work this is.
After I playing a bit with formulas and that online tool I beginning to realize you are right about the accuracy and that this resection method just won't do.
And you are right about the second part too. That's exactly what the surveyors here do. They find those old monuments and then place their measurement tools on it. I found out about that today.
So will focus on that.
Thank you all for your help. I am a bit wiser now than before I came here 🙂
:good:
