non surveyor looking for info please

I'll bite. Why don't you hire a surveyor ?

The problem will not be actually locating the precise coordinates by today's standards. The problem will be knowing what datum your 140 year old coordinates were established from. You can use a GPS from walmart and get better accuracy than many of the best surveyors 140 years ago.

Precisely locating coordinates on the ground in either WGS84 or NAD83 may still be several hundred feet from where you want to be.

James

actually a french word

voila
literally SEE THERE

Jaro nailed it. You don't want to find 'precise coordinates'. You want the original location. The two are rarely the same thing...

I take it this is not a property boundary? Even so, if points were determined by a surveyor in the past, a professional surveyor is likely your best bet today for relocating them.

You do need to get somebody with a good background who will take time to understand your situation. This is likely not going to be a typical job for them. Researching how the original coordinates were determined is essential.

It would help us understand your problem if you told us more about the situation. Perhaps an archaeological project? Or a treasure hunt? Or an oil well or mine?

How accurately do you think you need the results to succeed; 100 yards, 5 feet, 2 inches, or what? No measurement is perfect. "Precisely to seconds" would indicate on the larger end, since a second of latitude is on the order of 100 feet.

Do you have any reference point known on the ground for the old coordinates, that measurements can be taken in relation to?

If something was done 140 years ago in latitude and longitude, you can expect serious differences from what GPS measures, due to 1) inaccuracies that were inherent in the methods available, and 2) changing definitions (astronomical vs geodetic, new datums being adopted, etc.)

However, if you have a known point on the ground in the old coordinate system, a surveyor will be able to locate the other coordinate points as accurately as they were originally set.

To obtain an exact location with modern survey grade GPS is just kind of pushing a button and BINGO, you have an answer. Like someone else pointed out, how were the numbers obtained 140 years ago? Until modern times, it was not easy to do or that accurate. Also 140 years ago it was rare a surveyor even worried about what the Lat and Long were.

I will jump into what I think you need. You are working with a boundary. There is no list of Lats and Longs for boundaries. The Lats and Longs really have nothing to do with boundaries. If this is the case you need to hire a professional and let him do his job.

If this is not the case you need to tell us what the Lats and Longs are for and how they were obtained 140 years ago.

Yes i have accurately found every point that I set 100 even to 200 years ago with GPS. Are thing slow at the office or something?

hiring a surveyor is exactly whats on my mind..i was hoping for answers that would give me info on how to approach surveyor, like exactly how i wanted it done,,also, as i live in the country, the surveyors around here don't seem to be very knowledgable..hired one it took him 3 weeks looking over old deeds and walking around with a metal detector locating old property stakes just to mark property lines on a perfect rectangle 2 acre plot on perfectly flat cleared land that had only changed hands 3 times in the past hundred years..costed me $1000.00...a friend hired one to mark lines on over 140 acres, with numerous turns, all through all types terrain/brush/ponds/etc..took him 1 day and costed $300 bucks..so, do i need a big city surveying company, etc...these type quesions/problems are the reason for my original post...i am trying to figure out exactly what i need beforehand...kind of like this, we hired a very well known, world wide, geophysical company once to come out and do some surveys..we told them beforehand everything, type of soils, depth to bedrock, etc, all info they might need...they sent out a team, spent a day doing surveys with 3 types of equipment, charged us 10 grand, and as they were loading up their equipment they tell us that the results would be negligible due to the fact their equipment wouldnt work very well in the soils onsite....go figure..i'm trying to keep from having a repeat of that type occurance...also if you read one of the replies to my original post, its something like *SEE THERE*...its these type people i am looking to avoid, as end results have to be correct..there is no room for error..

Your coords are simple latitudes and longitudes. These are easily located today with precise GPS equipment. The issue is what was the basis for the original surveyed values? A careful review of the original notes and some geodetic adjustments will have to be applied to maintain the correct orientation of the survey. What those are is a matter of research and the skill/knowledge of a surveyor. Still, it will be an opinion based upon the best available evidence in existence to which to base the survey on today.
If you are willing to accept the responsibility for mis-locating many years of fieldwork, then by all means rent the equipment from a surveying rental agency and go to it. But having a trained professional do the real footwork and necessary adjustments is your best insurance.
Good luck.

... and these precise coordinates are relative to what exactly? By that I mean, what do these 140 year old coordinates have in common with WGS84 earth centered GPS coordinate sytem? That would be a good place to start. And without some evidence on the ground, how would you ever know if you got it right? Wait a minute...

This wouldn't be a search for buried treasure would it? o.O

Sounds as if the project is important to you and others. By your own account time and money have already been expended in the research. If you have legal constrains involved in your project a licensed surveyor is the only one that can testify in court as to the accuracy of retracing a 140 year old (1870s) survey. Many of us have retraced surveys several decades older.

As with any profession there are specialists within surveying. Most surveyors working in urban areas specialize in retracing smaller tracts and/or construction layout. Often these involve working from documents older than your project. Those working in rural areas are more experienced with retracing surveys of large areas. Again they often work from very old documents. There are surveyors that have experience in both types of surveying you need to select surveyors with the right type of experience and interview several.

Allow them to review your research. Often what non-surveyors believe is good documentation has little value while the less impressive document provides the correct answer to the problem. Also surveyors are often aware of documentation sources other researchers are not. Because of this no reputable surveyor is going to simply take your coordinate location and stake it on the ground.

For my money, I would rather go with the surveyor that performed in-depth research and took a little extra time instead of a shade tree surveyor rushing in just to get a quick dollar.

If you want something retracted to the original location, as accurately as possible, hire a surveyor that is going to research how the positions were determined in the first place (as suggested in many posts for this thread).

no idea on the datum..using a high end gps i can go to a marked point on the ground every day for a week and each gps reading will be different..when matched on delorme mapping program these gps readings have shown to be off as much as 1/4th mile..

As several other posts have said, 140 year old coordinates will not match GPS readings.

As to your repeatability, how far were they different? A high-end recreational GPS unit can easily have 10-20 ft differences even in a location with clear sky and much worse under tree canopy.

And what makes you think the delorme map is perfect?

If you have no idea about a datum, then you don't understand the situation well enough to see where the difficulties will lie, and you need to get expert advice, based on full disclosure to the expert of what you know about the source of the coordinates.

Tell us where the coordinates came from, and all the details of those old coordinates, putting X's in the first few digits if you feel a need for privacy, but giving us exactly the right number of places in the numbers so we can get a feel for what you have to work with.

to the seconds?

The nearest arc second is about 100'.

This is one of those posts that makes you wonder of some regular poster made up a new identity so they could tease us, then sit back and laugh at all the eager attempts to figure it out with never enough information.

It definitely sounds like a hunt of some sort. Share some details and you may get more help than you would anticipate.

My thought exactly Bill. If it walks like a duck, quacks like a duck but it's not a duck, then maybe I'm a turkey.

There was a good thread some years back about the corner common to New Mexico, Colorado, Arizona, and Utah ("four corners"). It seems some GPS'er looked for the latitude/longitude that the corner was supposed to be set at back when it was first surveyed. What they didn't understand was that it was based on a different zero-longitude. They came out several miles away and claimed that the corner monument was in the wrong place.

Coordinates can be based on a different origin point. Also, using a different spheroid model can distort the point locations (in relation to a different model). I good surveyor could figure out where the correct coordinate location is if he has enough metadata on what the 140 year-old coordinates were based on; and enough money and time.

(And yes, I think this sounds like a "prank" post. Still nothing wrong with discussing it. I think a lot of non-surveyors don't quite understand this issue)