How do you accurately find your property line to post signs and paint trees

[dodge man]

The problem with low end gps, such as smart phones, is there is no real indicator of the accuracy at any given time. For example survey grade and mapping grade give indicators of the quality of the results. I have experimented with different units in different conditions. In the woods you can get really bad results, over 100 feet of error.

 

[ericm979]

When using GPS to check against Google maps (or probably any maps) there are two different sources of error: the gps telling you where you are when you're trying to find the lines, and the maps. Often the maps have property lines or ROWs offset by 10-30' from where they ought to be. It's easy to tell when it's off, even for a property I've not been to- some of the property's buildings will be outside the property lines on the map, or the ROW for the road will be offset from the road in the map.

You can check the map's accuracy for your property if you know where the lines are supposed to be on the map. I know where two of my property lines are on the map (or rather the air photo superimposed on the map). Google has those right, so the other two are probably pretty good as well.

 

[dodge man]

A problem with maps or aerial photos is are they ground based and how are they lined up with boundary lines? We did the original ground control for our counties GIS system about 20 years ago. In that case we put out targets, big white crosses, that can be seen on the aerial fly over. This makes the aerial maps line up well with real coordinates.

The second issue is how are the boundary lines put in. We also did that for our county. They are just put in using the deeds and our best guess on what looks to be the boundary on the aerials. In other words, it might be close, it might not.

In the perfect world everyones property corners would have modern gps coordinates on them. That’s just not usually the case.

 

[lman]

The problem with low end gps, such as smart phones, is there is no real indicator of the accuracy at any given time. For example survey grade and mapping grade give indicators of the quality of the results. I have experimented with different units in different conditions. In the woods you can get really bad results, over 100 feet of error.

I have this on my phone.

GPS Test - Apps on Google Play

Get GPS and sensor information all in one place with an accessible format

play.google.com

 

[JethroB]

A problem with maps or aerial photos is are they ground based and how are they lined up with boundary lines? We did the original ground control for our counties GIS system about 20 years ago. In that case we put out targets, big white crosses, that can be seen on the aerial fly over. This makes the aerial maps line up well with real coordinates.

The second issue is how are the boundary lines put in. We also did that for our county. They are just put in using the deeds and our best guess on what looks to be the boundary on the aerials. In other words, it might be close, it might not.

In the perfect world everyones property corners would have modern gps coordinates on them. That’s just not usually the case.

That’s good to know. Thanks. My county’s maps seem to follow your comments. Good enough for now but if I or my neighbor on one side should ever cut the old timber a survey will probably need to be done. My dad used to say you mostly could find our property lines by looking at the size of the pines. Ours haven’t been cut or thinned since WWII. He called the big timber his bank, there for hard times.

 

[dodge man]

The best way to test gps is to find a known point. The NGS (National Geodetic Survey) has an interactive map that list known points. They are usually a brass disc. The problem is surveyors work in state plane coordinates, which is a northing and an wasting, and most phone and other lower end gps units work in latitude and longitude. You have to carry lat and long out to several decimal points of the seconds to really compare.

 

[s219]

The problem with low end gps, such as smart phones, is there is no real indicator of the accuracy at any given time. For example survey grade and mapping grade give indicators of the quality of the results. I have experimented with different units in different conditions. In the woods you can get really bad results, over 100 feet of error.

The data is available from the hardware, but it's up to the app to display it (or not). Many apps just draw a circle around the location on a map to qualitatively indicate accuracy. I always give the raw numbers in my software -- I'd rather have a hard number myself.

 

[rademamj1]

I used Google maps to draw lines to connect the corners of my property. I then could identify the larger trees, etc close to the line to give me a relatively good idea where the property line is. Crude, but good enough for my purposes.

I agree with this method. As long as you can get a reasonable GPS signal out in the field, take your lat/long readings on known boundaries and corner posts. Trees may degrade your signal and decrease accuracy. Add your GPS readings to Google Earth as data points. Draw your boundaries on the Google Earth imagery, displaying the latest or best year imagery available. Not all imagery is good due to cloud cover. Extract or digitize the Lat/Long for your drawn boundary line and print that file. Using your GPS locate those points in the field, and flag them. A Garmin GPS is good up to 3 feet accuracy.. Even a phone can be accurate to 10 feet or better. Thus, you should get a reasonable line of flags in the field.

However, A professional survey crew is the best way,, and most accurate way, placing your property boundaries for a reasonable fee, accurately to 0.10 feet using a commercial "differential" GPS. They will issue a report and survey map of their work, which is typically accepted by government agencies.

 

[oosik]

All of this so you can post some signs and paint a few trees purple???

 

[rademamj1]

All of this so you can post some signs and paint a few trees purple???

Nope. Posting of signs and painting trees purple, strictly assumes your property boundary is known accurately. But many rural property boundaries often are unmarked, unfenced and maybe not even surveyed. The more older and remote the property is, the more likely its never been surveyed. Commonly you see the fence lines marking property boundaries, but is that fence line accurate and properly positioned. You can do some quick checks with Google Earth, but ultimately a professional GPS survey is the best way to go.