What piece of electronics does one need to locate spots on a survey map?

[G+_Rud Dog]

What piece of electronics does one need to locate spots on a survey map?

[G+_Kevin Britain]

i think professionally they use a gps data logger, but i'm guessing if it's for home use you can use your mobile device..

[G+_Rud Dog]

Kevin Britain Thanks. Trying to find markers on property guided by surveyors map. Found it funny on the surveyors map saw something calling out plus or minus 40 feet.

Also having a hard time translating the info on the map for example

 

N X° X' X" Wxx.xx This is exactly how it is written on the map

WX° X' X" Wxx.xx Well the formatting real numbers were replaced

with X's.

 

I am familiar with the NX° X' X" but the second part is confusing me:

Wxx.xx

On google maps you can enter the information using this format:

x° x' x" N x° x' x" W but not sure what to do with the Wxx.xx which comes right off the surveyors map?

[G+_Jon Papai]

What that means is North, X degrees, X minutes, X seconds W xx.xx feet, i.e. direction and distance. This is a displacement from some known fixed point. They start from a stone set sometime in the 19th century at the corner of a square mile section, and then travel along the edges to another point, and finally to the "true place of beginning" at a corner of your property. They then use the above format to draw line segments around the edge of your property until they return to the "true place of beginning"

 

For instance N 87° 0' 0" W 320.00 would be a line segment 320 feet long 3 degrees north from westward. Strangely enough, they don't seem to use true north, at least not where I live.

 

Property corners are usually marked with a long piece of steel rebar pounded to terminate a few inches deep. A metal detector is the most useful piece of equipment. There is usually a plastic cap atop that rebar with the surveyor's name on it. Developers usually subdivide in the middle of a public road. That would be the best place to start looking for a property corner. Once one is found, an old fashioned GPS with WAAS seems to be good withing a few feet of finding the other end of the line segment.

 

As far as converting the Public Land Survey System to GPS, this website apparently will do it, though I could not get it to work : legallandconverter.com - Public Land Survey System

[G+_David Wiggins]

Jon Papai?, just wanted to say thank you for that detailed response. That is an excellent data dump.

[G+_Rud Dog]

Jon Papai Thank you for clearing up the survey map and its markings. I was with you till you mentioned "3 degrees north from westward"

Where in this info did you get the 3 degrees?

N 87° 0' 0" W 320.00

Appreciate the your time and help.

[G+_Jon Papai]

They measure from north and south, so N angle W means North then angle degrees toward the west. so N (87 degrees) W would be almost westward. (please see graphic)

[G+_J. Peter Haliburton]

I work in land surveying. Quadrant bearings can take some getting used to.

[G+_Rud Dog]

J. Peter Haliburton I am trying to walk the property and write down the readings for comparison to the existing survey map.

One part of the map readings has me a bit baffled. They mark off a spot on the make then go from the center of that line either west or east. Why not just find the coordinate and walk off in the direction like West, East, North or South?

[G+_J. Peter Haliburton]

You can convert from quadrant bearings to azimuth. Any in the NE quadrant will be the same as the azimuth. Your survey is probably tied to grid north, not magnetic.

[G+_J. Peter Haliburton]

This is the way we do it, but our system uses a 3° MTM projection:

 

Bearings are labelled as starting from the center of the + (in the image below). Generally the bearings run clockwise, but you may have to determine that from the drawing.

 

With N 87° 0' 0" W, you read it as "from a line running due north, turn an angle 87° to the west." That is the same as a line running 3° north of west, as previously stated by Jon Papai?. That would give you 270° + 3° = 273° to read on a compass. You will have to adjust for whichever N your plan is referenced to, and the difference from that to the current magnetic north in your area.

[G+_J. Peter Haliburton]

We have very accurate GNSS systems at work, but a common handheld receiver will generally get you within 3m. Sometimes it is easiest to just use a measuring tape, or pace off the distances, if you have something to use as a starting point, like a known pin, and a general direction, like parallel to a road or fence.

 

I have setup drawings at home in LibraCAD to get coordinates to enter into a personal GPS receiver, but you will need some sort of reference. That should be on the plan. We have government installed control monuments, with known coordinates, to reference our surveys to. For our 3° MTM system, the settings have to be changed in my eTrex to a user defined one where the Longitude and False Easting can be entered.

[G+_Rud Dog]

J. Peter Haliburton The time you have spent to enlighten me is much appreciated. Now I will attempt a test map on my own "in the city" property. Again thank you.

[G+_J. Peter Haliburton]

Rud Dog For what you want to do, I didn't know if I was being helpful, or making it more confusing. Let me know if you need anything clarified.

[G+_Rud Dog]

J. Peter Haliburton The land in question is in an area of steep but walk-able terrain. The land was surveyed years ago and a map was provided. Since that survey the metal markers were lost some to county improvements and others to plane plant growth. What I would like to do is take the map and the coordinates and try and locate markers and property lines.

After reading your input and googling the heck out of this method of surveying decided to review the map again and show what I think to be called out coordinates.

The first coordinate, N7° 3' 31" W32.32 which I take to mean in the real world go to the location called out in the first part of the reading which is North 7 degrees 3 feet 31 inches, mark this spot. From this spot travel West 32 feet and 32 inches mark that spot.

Next go to S5° 48' 21" mark the spot then travel East 32 feet and 43 inches mark that spot.

If this makes any sense then I know I can take the map and find the locations documented. There is one thing I find interesting I found what appears to be a tolerance and it was plus or minus 40 feet or inches as the copy I have was blurred. If it was 40 inches then this is an acceptable tolerance. Don't know what the tolerance of the software on my cell phone is but that can be tested when I travel to the parcel.

Last question. When the GPS units started showing up for sale I purchased the Garmin unit apparently used for maritime use my questions is; Is this unit anymore accurate then my cell phone app?

Of course will test but have to dig it up if I can remember where I put it.

Your input has sparked a new interest in surveying, thank you.

[G+_J. Peter Haliburton]

Rud Dog There should be a starting point in some coordinate system, or a tie to something that existed at the time of the survey, like a road intersection, or church corner.

 

From that established position, you would then follow the bearings and distances. A metal detector may be useful in finding the iron pins.

 

Older surveys were done with equipment that is not nearly as accurate as we have today. We sometimes have to convert some century old plans which were done with 66' long chains (https://en.wikipedia.org/wiki/Chain_%28unit)). The distances on those may be stated as "more or less", and the closure can be out several feet. Measuring over slopes can introduce errors too, since the plans show horizontal distances.

 

A modern phone is probably more accurate than an old handheld GPS receiver.