# What is a good gps for locating property marker?

Asked by

monmac (

7)
January 6th, 2014

If possible suggest type and brand that will do the job in searching marker.

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## 9 Answers

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I use my Garmin GPSMAP 60CSx and let it average for a few minutes. It is always spot on.; (within the size of the GPS! Make sure to average for a while. A single reading can be off by a meter or more depending upon the number of satellites.

I can not thank you enough. The surveyor who did it 9 years ago wants $1800.00 for 10 acres irregular shape property. I have the map/plat from my county and i want to do it now while the leaves are gone. Again thank you for the quick response.

If there was a survey done before there maybe metal pipes buried at the corners and mark points. You may have a local tool rental agency that will rent it to you for a day at a reasonable cost. Use paint to mark the points ( surveyors use orange or pink streamer in the brush overhead ). Start with a point on the plat that is easy to find like telephone pole or neighbors fence.

@monmac I was in the same position – a 20 acre parcel in the middle of nowhere that had been surveyed 50 years ago. Two of the pins were in place and readily available. The other pins were in the woods about half a mile away. I used high school trig to figure out the relationship between feet and degrees and was able to find the missing far corner of the property right on! I found the barbed wire fence that had fallen and was hidden by decades of leaves and branches. An old tree (hickory) had three hatchet cuts on one side right where the GPS lead me.

To run the 2000+ ft survey line myself, I got orange flags from the hardware store and stuck one in each corner of the property. then I made a spread sheet with the GPS locations calculated every 50 ft . I had a friend mark the 50 ft and 100 ft points while I sighted through my rifle scope as a check to make sure it was still in a line. Then I went to the 50 ft point while he went to the 150 ft point and marked it. And so on. When I got to the end I was only off by about a foot. I then promised myself I would work in the other direction to make it perfect but after about 10 minutes I decided it was good enough.

Those geometry and trigonometry problems from high school paid off. ;-)

Welcome to Fluther! May all your property lines be straight.

I forgot to mention my GPS is probably 4 years old. That is like 100 in GPS years. ;-)

I’m sure there are cheaper and better models out there now. Make sure is says WAAS enabled.

For any GPS you purchase the trick to achieving best accuracy is to let it average for a while. 2 minutes, 3 minutes. (As a test, I tried going to 20 minutes once but did not see any difference after 5 minutes.)

A metal detector is helpful too. Borrow one from a friend or check GoodWill and Craigslist Someone in your neighborhood is selling one for $10 right now.

Sorry to bother again. On the plat, between two points there is a coordinate and a distance. Which of the two points from the data refer to a marker. I thought a coordinate represents a point in the gps. I’m trying to copy/paste the map here but it does not allow me.

thanks again

I am not sure about your question. Usually the plat map starts from a known marker. It might have a gps coordinate attached to it or it might just be a pin in the ground that was put there 50 years ago. Just like the surveyor you must start with one point you can identify. There might be a cement marker in the ground someplace nearby. They look like this or similar. Or your property might have a pin located someplace. Then you move in the direction stated on the plat map. A good compass will point you in the right direction. Or you can use the distances on the plat map to figure out the latitude and longitude of the points from the known point you measure with waypoint averaging.

This method uses brute force trigonometry. Here is how it works – roughly.

The earth is 40000 km in circumference. You can find the real number. A circle is 360 degrees. That means for latitude 1 degree is 40,000km /360 deg = 111 km per degree. or 1.8 km per minute. or 30 meters per second. If you have your GPS set to deg and minutes (no seconds) that means it is 1.8 meters per 0.001 minutes. So that is good guide for walking North – South .

Now let’s go East and West. The Earth is nominally a sphere so at the equator the distance would be the same at North south. But you do not live at the equator. Lets say you live at 45 degrees latitude. That means you need to multiply the 1.8 meters per 0.001 minutes by the Cosine of 45 deg or 0.707. So 1.8 m x .707 = 1.27 m per 0.001 minutes.

Get it? If our lines are not East – West or N -S then you have to use geometry to figure each component. It is not that hard. It is just tedious. If might take you a few hours. Less if you use Excel. But so what. If it takes you 8 hours to figure it all out and you save yourself $2000 isn’t it worth it? You are paying yourself $250 per hour! Tax free!!!

Aren’t you sorry you didn’t listen in math class. Maybe your kid did. ;-)

I recently (Fall 2013) reviewed the current Garmin GPS models with this purpose in mind – finding approximate property corners. I wrote up my findings in a PDF file and also made a spreadsheet comparing the models. For this purpose I recommend:

Garmin eTrex 20. Buttons. $200

Garmin Oregon 600. Touchscreen. $400

My analysis plus some other articles I wrote related to using a GPS to find approximate property corners is at: http://www.propertylinemaps.com/p/plm_gps_tips.html

@monmac – That is not a “coordinate” you see on your plat map. Instead, it is a compass bearing expressed in surveyor-speak. For more info, google: survey quadrant bearing

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