running a straight line through trees

Page 1 of 3  

We've got a bunch of woodland that's partly on our property and partly on a neighboring (vacant) plot. Runs for about 300' or so, and there's a boundary marker either side of the woods.
I'd quite like to add a few more markers within the trees, just so we know where the boundary is (and maybe fence at a later date) - question is, how to mark it out? The woodland's too dense to see through to the other side, even at night with a flashlight on one of the markers, so I can't just walk and "home in" on it.
I'm not sure that GPS is accurate enough to do it that way - any other clever tricks?
Did wonder about running two lines, meeting at one of the markers. All I need to do is get them straight through the trees (which might be a challenge in itself) - then I can presumably measure distance from each to the other marker at the far end, translate that to a scrap of paper, and calculate where the "true line" is between the two markers for any given distance along one of my guide lines. Does that make sense? Maybe there's a simpler way, though...
Ideas on a postcard, or on usenet, whichever is easier.
cheers
Jules
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

You did not say why. If you are just looking for a general idea of how big the lot is, then running down the trees is okay. If you want to actually do something like build a fence, etc., then you probably should get it surveyed.
--
To find that place where the rats don\'t race
and the phones don\'t ring at all.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thu, 19 Nov 2009 16:54:28 -0500, Kurt Ullman wrote:

Ahh, there's a possibility that the vacant lot is going to be sold, so I figured I should maybe mark the line a bit better than just the two boundary poles. The lot's shaped such that any buyer would be unlikely to pull trees down to put a building in (it's about 4 acres I think and the extra effort of taking down an acre of trees doesn't seem sensible) - but some folk can be strange :-)
We might just buy it ourselves eventually, but have too many financial commitments for the next 3 months to think about that (OTOH once the snow hits I bet it won't get much interest until next Spring)

Yes, calling in a professional is one option, although I'm curious how they do it when they don't have line-of-sight either. I doubt 6" either way is any big deal (it's just not the sort of place where people get pissed about that kind of thing!) but I'm not sure if GPS is quite that accurate (at least not the civilian stuff)
cheers
Jules
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Then it would have to be surveyed, at least according to the way they do things around Indy.
--
To find that place where the rats don\'t race
and the phones don\'t ring at all.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Kurt Ullman wrote:

But all they would do would be to confirm the location of the existing boundary corners--no need to survey where the straight line between two marks actually runs for the legal description so they won't do so.
As for finding the line itself lacking line-of-sight, manually it's painstakingly working one's way thru from one sighting to another.
I don't know what the inexpensive handheld GPS gizmos can do; I've never had one or looked to see as never really cared that much. BUT, US WAAS static accuracy is +/- (roughly) 30". This is what's freely available but not guaranteed availability.
Additional corrections can be made to a single signal but afaik these are all subscription services and whether the cheapie devices include that cost in the upfront purchase cost I don't have a clue.
We use John Deere AutoTrac(tm) with their proprietary SF2 subscription service on the tractors/spray rigs/etc. which has an absolute static accuracy of +/- ~10" but repeatability of tracking of better than half that (the latter is the more critical for our purposes of controlling row spacings and spray coverage as opposed to your desire to know where a point is physically located).
So, all in all, I don't know what you could get inexpensively but I'd expect more like the 30" rather than the 10" numbers.
FSA (USDA Farm Service Agency) uses GPS to do monitoring/compliance on acreages but they, of course, have access to whatever level of technology the DOA(griculture) has access to. They routinely print out computer-generated maps down to the 0.0001 mile (1/2") but I seriously doubt the data are that accurate only that that's what their silly compter output formats are. I'd guess they're roughly at the 10" value overall although I don't think any of the technicians nor even our office director have that level of knowledge of the technical details--only how to use the supplied equipment and software systems.
I routinely measure fields by the rolling wheel technique for waypoints in the total field for operations such as haying or similar and ignore anything less than roughly 1/10A (which is a strip roughly 1/2-ft wide over a half-mile row) and have never been called to task. That close is reasonably easy to get as each revolution on a rod wheel is 1/4 of 16.5-ft or 4+ ft so 1-ft is a quarter revolution. 1-rod by 1/2-mile is 1A and most of our land is farmed in quarters which are 160A or 1/2-mi square so that's far more convenient measure rather than feet-inches by hand. The JD AutoTrac readouts can be switched to whatever units one wants since it's all computer-based, of course.
But, all that to say the higher accuracy GPS numbers above don't come cheaply (at least w/ green paint (or red, either, for that matter).
--
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thu, 19 Nov 2009 16:08:45 -0600, Jules

No, a GPS is definitely not accurate enough for that purpose.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thu, 19 Nov 2009 17:21:44 -0500, snipped-for-privacy@dog.com wrote:

The surveyor I talked to during the summer told me that his old model was accurate to an inch, and his new model to a tenth of an inch.
I think these were 20 to 40,000 dollars, but still they meet the definition of a GPS. :)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

I seriously doubt the OP was talking about the very expensive and accurate type of GPS used for surveying. I'm not sure one would work for his particular application anyway, as those units need open sky above to achieve that accuracy. This is a thick grove of trees...
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thu, 19 Nov 2009 21:34:45 -0500, snipped-for-privacy@dog.com wrote:

Good point. Not sure but maybe I just wanted to tell about how good the expensive ones are.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
on 11/19/2009 9:34 PM (ET) snipped-for-privacy@dog.com wrote the following:

Not only that but public grade GPSs can be off by a meter (3' 3")
--

Bill
In Hamptonburgh, NY
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

As has been pointed out, surveyors have GPS devices that cost a lot of money, and are accurate to 5 millimeters. We are not talking about inexpensive consumer units that tell you to turn left when the road curves right.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Nov 20, 5:58�am, snipped-for-privacy@dog.com wrote:

wonder if you can rent one of those super dooper GPS units?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Fri, 20 Nov 2009 05:03:39 -0800 (PST), " snipped-for-privacy@aol.com"

Doubtful. You would also need to hire the guy that knows how to use it. At that point, you have basically hired a surveyor anyway, so what's the point?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Nov 20, 8:08am, snipped-for-privacy@dog.com wrote:

re: "so what's the point?"
The point is that this is a DIY group. ;-)
Money is not the point - it's the thrill of the fight!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Fri, 20 Nov 2009 06:10:15 -0800 (PST), DerbyDad03

Oh, I disagree. I think hardcore DIY'ers have frugality as part of their DNA. They want to do it better for less than it would cost to have someone else do it.
credo:
Use it up Wear it Out Make it do Or do without
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Nov 20, 9:26am, snipped-for-privacy@dog.com wrote:

So if you rented the GPS *and* the guy who knows how to run it at the same cost of as simply having the survey done, would you not be out in the woods holding the GPS with the guy looking over your shoulder (making sure you used it correctly)?
I know I would be. My curiousity would make me do it.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Fri, 20 Nov 2009 07:19:44 -0800 (PST), DerbyDad03

My guess is that they charge a lot more if you insist on "helping" them. And you really wouldn't be doing it yourself, anymore than following someone else around as they build your deck for you.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Nov 20, 10:36am, snipped-for-privacy@dog.com wrote:

OK, we're picking the proverbial nit here, but your deck analogy doesn't match the situation I described.
You used "following the deck guy around" and I said the "GPS guy was looking over my shoulder". I would be doing it myself, but with his guidance, just as if I was holding the screwgun and the deck guy was telling me where to put the screw.
As far as "guessing" that they would charge more to let me help, keep in mind my original premise: I rented the GPS and the guy for the same price as getting the survey done. I wasn't suggesting hiring the survey company and then insisting that they let me help. This is a "side job".
Assuming the GPS was actually available for rent (and that may be the biggest obstacle) then it's extremely possible that the "guy" would be willing to make a few extra bucks on a Saturday afternoon by doing some free lancing. This is not such a far fetched premise. The GPS owner makes money on his GPS when it would otherwise be sitting on a shelf * and the "guy" makes some extra pocket cash.
* I went to a 40th birthday party that was staged as a funeral (the end of the guy's "former" life). They paid a funeral home $50 to park a hearse in the guy's driveway during the party. It was a Friday night, the hearse wasn't being used, so the funeral home made a little money on an asset that would have been idle.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Fri, 20 Nov 2009 08:27:44 -0800 (PST), DerbyDad03

yes, you are picking nits.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
DerbyDad03 wrote: ...

I don't know the system surveyors use but the aforementioned FSA (Farm Service Agency) system works in one of two ways.
To lay out a field they start by downloading waypoints into a handheld device and then all they do is find the point(s) where the device registers a null deviation.
The specific points include all boundary corners and the (I presume internal) software provides the target for straight line(s) between those points.
Alternatively, the field technicians survey fields by simply driving to the boundaries of the area planted, say, and at each corner and along the way every so often "mash a button" and that records a set of coordinates. These are then uploaded from the device and converted into maps and acreages, etc. back in the office.
Doesn't seem much to it altho I've not actually pushed the buttons I'd presume their systems are similar.
Somebody else mentioned the 5cm/2in precision -- seems like I'd heard that kinda' numbers before but not positive whether that's really so for absolute position or only for relative. As noted above the quite-pricey (at least for DIY use) auto-track ag systems are about twice that. Of course, there's a lot of ancillary stuff besides the GPS system in those and impossible to back out what that alone would be. But, the software systems supporting it aren't giveaways I'm sure despite the fact it doesn't cost anything to duplicate there're non-insignificant development costs to amortize there...
--
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Site Timeline

Related Threads

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.