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GPS Unit for Large Parcels


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I retired to an old 285 acre farm that has been in the family over 100 years and has not been active (used) since mid 1960's. The farm consists of three parcels of approximately 120 acres, 90 acres and 75 acres. About 60% of the land is forest. Most of the corners are well marked with stones and steel posts. Some of the property lines are over a half mile long through woods, over hills and across streams. I would like to know where the property lines are located in between the corner markers. The lines don't have to be exact but I would like to get within say 6 or 8 feet to enable harvesting some timber. I have an older Garmin GPSmap 76CSx unit that is 10 or 12 years old but have difficulty getting repeatable results. Is there a hand held GPS unit available which would help to identify where the boundary lines are located?? Thanks.

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This is not a geocaching question but...

 

Fire up the old unit (its accuracy should be fine) and create a route along the property boundary, corner to corner. That'll display on the screen, and as you walk close to the boundary line, you can zoom in and see which side of the line (route) you're currently on.

 

Does that help?

Edited by Viajero Perdido
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This is not a geocaching question but...

 

Fire up the old unit (its accuracy should be fine) and create a route along the property boundary, corner to corner. That'll display on the screen, and as you walk close to the boundary line, you can zoom in and see which side of the line (route) you're currently on.

 

Does that help?

Yes, I know it is not a geocaching question but from past experience (years ago) I know there are some very GPS knowledgeable people here on this forum. My present GPS unit is over 10 years old and I'm fairly certain there are newer units available that are: 1) more accurate,and; 2) faster. That is probably the way I should have phrased my original question. Using my older Garmin GPSmap 76CSx, I'm having difficulty with accuracy getting repeatable results when walking a line. Perhaps my unit is defective. I could get a surveyor to mark the lines between the corners which would cost several thousand dollars. However, I thought there would be a newer GPS unit available that would get within 6 to 8 feet which would be fine for what I need.

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OK, here is what I would do on my not too busy, straight, residential street:

1. Record a track on my GPSr while walking down the center of the 4 ft wide sidewalk,

2. Upload the track as a GPX or KML file to Google Earth,

3. Zooming in sufficiently with the aerial, photo imagery visible,

4. I would make a quantitative evaluation regarding the recorded track relative to its surroundings.

Edited by Team CowboyPapa
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However, I thought there would be a newer GPS unit available that would get within 6 to 8 feet which would be fine for what I need.

Though newer units may have more tech, a GPSr itself probably may not be as accurate as you'd like.

We've found our old 60cxs' are still just as "accurate" as a friend's oregon 600, and the other 2/3rd's iphone7.

Go figure...

The government (DoD) I believe sets civilian GPS "accuracy", and still has us at 10' on a "perfect" day. :)

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OK, here is what I would do on my not too busy, straight, residential street:

1. Record a track on my GPSr while walking down the center of the 4 ft wide sidewalk,

2. Upload the track as a GPX or KML file to Google Earth,

3. Zooming in sufficiently with the aerial, photo imagery visible,

4. I would make a quantitative evaluation regarding the recorded track relative to its surroundings.

 

And then repeat 10 times each on 10 separate days (total of 100 samples) and you'll get an idea of location variation within and between days. But an open sidewalk is also different than in the middle of dense woodlands where the variation will be considerably larger - with 95% of samples being within oh... up to 100 feet from the true location.

 

If the coordinates of the corners are already known, then half your work is cut out for you. One way to survey the line is to use a compass and mark it in small sections, first using stakes and flagging, and later with paint on trees along the line. You can still accumulate error this way, but you can compare this error over long intervals with the GPS (use waypoint averaging to get your location) and correct it. You could also rent/borrow surveyor's tools which include scopes with compass sights and even laser beams to precisely follow a direction while measuring distance, slope, etc.

 

Whatever the method to your madness, after marking the boundary, it might be wise to allow yourself a buffer where you don't harvest any timber near the border.

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I retired to an old 285 acre farm that has been in the family over 100 years and has not been active (used) since mid 1960's. The farm consists of three parcels of approximately 120 acres, 90 acres and 75 acres. About 60% of the land is forest. Most of the corners are well marked with stones and steel posts. Some of the property lines are over a half mile long through woods, over hills and across streams. I would like to know where the property lines are located in between the corner markers. The lines don't have to be exact but I would like to get within say 6 or 8 feet to enable harvesting some timber. I have an older Garmin GPSmap 76CSx unit that is 10 or 12 years old but have difficulty getting repeatable results. Is there a hand held GPS unit available which would help to identify where the boundary lines are located?? Thanks.

 

Send me ALL the data you have - such as any known gps marked property coordinates you have identified to the best of your ability, and any line call data from the property deeds - and I will process it and see what you have. If any data seems to be missing, we can discuss what else is needed. It is amazing what you can deduce with aerial images, AutoCad representations and overlays, and geograpcic calculators. Obviously NOT to the standard of an actual professional surveyor, but pretty darn good amateur quality. I have processed this type of data many times. It is actually quite easy once you have figured out how to do it. Not so easy to explain to those who are mostly confused by the process.

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I retired to an old 285 acre farm that has been in the family over 100 years and has not been active (used) since mid 1960's. The farm consists of three parcels of approximately 120 acres, 90 acres and 75 acres. About 60% of the land is forest. Most of the corners are well marked with stones and steel posts. Some of the property lines are over a half mile long through woods, over hills and across streams. I would like to know where the property lines are located in between the corner markers. The lines don't have to be exact but I would like to get within say 6 or 8 feet to enable harvesting some timber. I have an older Garmin GPSmap 76CSx unit that is 10 or 12 years old but have difficulty getting repeatable results. Is there a hand held GPS unit available which would help to identify where the boundary lines are located?? Thanks.

 

Send me ALL the data you have - such as any known gps marked property coordinates you have identified to the best of your ability, and any line call data from the property deeds - and I will process it and see what you have. If any data seems to be missing, we can discuss what else is needed. It is amazing what you can deduce with aerial images, AutoCad representations and overlays, and geograpcic calculators. Obviously NOT to the standard of an actual professional surveyor, but pretty darn good amateur quality. I have processed this type of data many times. It is actually quite easy once you have figured out how to do it. Not so easy to explain to those who are mostly confused by the process.

 

Thanks for the offer. My deeds originated around 1860-1865 and have whole angles and distances in perches. The plot descriptions are still recorded the same way at the county records office. I've tried plotting the deeds using software and none of the parcels close. The best thing I can use for corners are stone piles, steel rods, and in some cases trees with markings. So I don't have a good accurate written description of any of the parcels, i.e., angles and distances.

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I was told (surveyor) the old original deeds were simply property descriptions used for taxing purposes and that the actual parcel markings like stones, steel rods, trees, fences, and etc, denote property lines and carry more weight in a court of law. There are no boundary line discrepancies with the neighbors since all corners are well known. Most of the neighbors also have large parcels and have cut timber on their properties over the years --- they just don't cut any where near where they believe the boundary line is located unless there is an old fence row. I may wind up hiring a surveyor if the GPS method doesn't work.

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I was told (surveyor) the old original deeds were simply property descriptions used for taxing purposes and that the actual parcel markings like stones, steel rods, trees, fences, and etc, denote property lines and carry more weight in a court of law. There are no boundary line discrepancies with the neighbors since all corners are well known. Most of the neighbors also have large parcels and have cut timber on their properties over the years --- they just don't cut any where near where they believe the boundary line is located unless there is an old fence row. I may wind up hiring a surveyor if the GPS method doesn't work.

There's no reason you can't use your current device to take some averaged readings at the 4 corners. Then create a square track in Basecamp and edit the coordinates of the corners to match. Send that to the GPS and turn on the track display. That should get you an accuracy of +/- 20 feet or so at worst. If you need higher accuracy than that, you might have to hire a surveyor.

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There's no reason you can't use your current device to take some averaged readings at the 4 corners. Then create a square track in Basecamp and edit the coordinates of the corners to match. Send that to the GPS and turn on the track display. That should get you an accuracy of +/- 20 feet or so at worst. If you need higher accuracy than that, you might have to hire a surveyor.

 

News flash. There are many property parcels that are not square or rectangular. They can be very irregular, with some angles that do not immediately bring the boundary line around to closure. So any reference to "the 4 corners" can not be universally applied. I take special pity on anyone who has to rely on Basecamp to visualize, familiarize themselves with their property lines. I don't have the best professional tools for the job, but thankfully I have never had to use Basecamp.

 

I would still like to see what information this property owner does have in angles and perches, and can personally mark with a GPS. I could figure something out, and might even learn something in the process about old deeds.

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There's no reason you can't use your current device to take some averaged readings at the 4 corners. Then create a square track in Basecamp and edit the coordinates of the corners to match. Send that to the GPS and turn on the track display. That should get you an accuracy of +/- 20 feet or so at worst. If you need higher accuracy than that, you might have to hire a surveyor.

 

News flash. There are many property parcels that are not square or rectangular. They can be very irregular, with some angles that do not immediately bring the boundary line around to closure. So any reference to "the 4 corners" can not be universally applied. I take special pity on anyone who has to rely on Basecamp to visualize, familiarize themselves with their property lines. I don't have the best professional tools for the job, but thankfully I have never had to use Basecamp.

 

I would still like to see what information this property owner does have in angles and perches, and can personally mark with a GPS. I could figure something out, and might even learn something in the process about old deeds.

Each of the three properties have more than four corners and none of the corners are square. I could obtain the coordinates of one of the properties and see how that works out. Some surveying has been done with one parcel so there would be some data to compare with. I have an external antenna for the 76CSx if that would help with accuracy though I haven't used it much.

 

I live in central PA and am currently on a trip to Raleigh and won't be able to get to it for at least a week.

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It is a small world. I am in Southeast PA, and have been known to venture West on occasion. Yes, when you are able, send me what you have for the best documented parcel. After seeing what I can do with that data, perhaps you will be interested to see what I can do with the other two.

 

This is something I took an interest in when I had no idea what I was looking at and no clue what I was doing. Since educating myself as much as possible, it is now just another one of my recreational pastimes.

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I work in the GIS field and have used tax parcel shapefile data to roughly locate property boundaries to help our survey crews get started. For PA I just found this site for PA Spatial Data. If you find your property and provide the address or PIN Number it is possible to convert the parcel data to .gpx format to load in your Garmin. Depending on the parcel data source the accuracy could range from sketchy to quite good. Some such data is digitized from hardcopy tax maps (sketchy) and some comes from actual survey data (quite good).

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There's mixed quality advice above. If you're making legal decisions, such as giving directions to a timber harvester, the advice to not save a few hundred bucks on a surveyor seems sound. Sounds WAY easier than defending against property damage and "theft" when a timber harvester drifts too close to the edge. But I'll leave legal to legal experts and focus on the technical.

 

Consumer grade GPS is still rated 3 meters in fantasy conditions. Newer GPSes make that fantasy more likely, but you're still at about ten feet - and in the woods, on a hill, surrounded by cliff walls isn't it. Your 76CSx, used properly, will be about on par with what you can buy today. But you're going to have to work for it. Hint: the single least expensive upgrade you can make. You want approximately this, but double check that connector type.

 

As for the accuracy while walking a line, observe that specific model, I actually wrote up a (nearly forgotten) article on that very device over ten years ago at http://www.mtgc.org/robertlipe/showdown/ The SirfStar III chips in those had three modes, IIRC. "Track Smoothing" which would compute your moving velocity over time and figure you were probably continuing in about that direction at about that speed (your hike wasn't going to become a jet in two seconds). This had an effect very much like the famed Magellan "overshoot" from the early 2000's. "Static Navigation" where the math would assume you weren't moving 1m this way, .7m that way, .4m that way, etc. in adjacent seconds: you were probably stopped at a stop sign or resting on a bike. There was also the "raw" mode where every little jitter was reported. When you weren't using waypiont averaging (which we assumed was done by software off the Sirf/MediaTek cores) we deduced this generation of devices was using the latter. So if you really wanted good position from these, be prepared to use waypoint averaging over time.

 

But you really should temper your expectations reasonably. If you're expecting to walk 1.3 miles in the woods over terrain following an arrow with a spray can and tell your loggers that anything on that side of the line is fair game, well, that's just not reasonable.

 

I have over a hundred GPSes (yeah, really) and there have been times I've taken a dozen or so of the 'best' for a joyride. Even at auto speeds (my car moves further in a second than you do on foot in the woods, so that 3m matters less) there's some pretty crazy jitter. There are good reasons the GPSes on each end of the blade of the dozers sloping that curve in the road are getting additional help from pro grade gear.

 

As for being "not strictly geocaching related", while I happen to be one of the moderators, I also allow some leeway based on community feedback. This post flushed out many experts that have been here a long time that were willing to help. If your account was created to ask "how I hack the gps to track my cheating spouse's cell like Will Smith does in the movies" or "who knoz the best fleet tracking device?" when you have no finds or hides, but your signature and profile says "contact me fo rthe best fleet tracking gps device", I'm going to have a good day making you have a bad day. :-) We do have some reasonable percentage of the world's (mostly non-professional. mostly.) experts on this tech represented here...and they're pretty consistently telling you to seek professional help (some are even offering it) for more than rough sketches. But as a moderator, I'm going to do my best to strike a balance of 'interesting' and spam-free.

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Each of the three properties have more than four corners and none of the corners are square. I could obtain the coordinates of one of the properties and see how that works out. Some surveying has been done with one parcel so there would be some data to compare with. I have an external antenna for the 76CSx if that would help with accuracy though I haven't used it much.

 

I live in central PA and am currently on a trip to Raleigh and won't be able to get to it for at least a week.

Dear OPIE:

Perhaps you should give up on amateur surveying, as your JOKBUS was spotted on the West Coast, not the East, close to our boundary line last night just before the basketball game. I would also point out that the missus just bought a new chain saw. Have a good trip home.

39_Steps

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