Recently we surveyed a 4 acre vacant lot, half cleared and half not. The client plans to build on the lot and we all know we can't plan on where they want to build so when elevations are ordered they have to be gotten. Half was wide open and the rest looked like this.
We chopped a little path through finding the open spots, and with an antenna height of 14.56' we were able to get a decent topo of the area without a great deal of cutting and traversing carrying an HI and the works. 14.56' is not the highest I've ever had it, I had a party chief tell me, "you are not a surveyor until you can master this thing" referring to a telescoping 22' pole with a Bluetooth capable RTK antenna on top. What a pain to have an antenna so jacked up, when it leans, it leans. But when plumb and measuring with a fixed solution it is quite the event. This is what our GS14 looks like 14.5' above the canopy. +/- 2 acres never seemed so big.... Not sure even [USER=291]@Nate The Surveyor[/USER]'s Javad would measure okay here without some high rod.
I turned the photo black and white because the cloudy sky background under the dark canopy showed hardly any color anyway, and with color it was rather pixelated.
Good GPS... Ain't it grand?
GPS...It seems so much like cheating!
What I hate about topo on lots like this, is that the first thing the client does when he gets your topo is bulldoze the lot clear because all the brush is in his way. Well, it was in MY way too!
Gromaticus, post: 372200, member: 597 wrote: GPS...It seems so much like cheating!
What I hate about topo on lots like this, is that the first thing the client does when he gets your topo is bulldoze the lot clear because all the brush is in his way. Well, it was in MY way too!
Find a crazy landscaper with a tractor mounted brush cutter without the safety guard. The understood mess would be gone in no time.
Or lidar.
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Gromaticus, post: 372200, member: 597 wrote: GPS...It seems so much like cheating!
What I hate about topo on lots like this, is that the first thing the client does when he gets your topo is bulldoze the lot clear because all the brush is in his way. Well, it was in MY way too!
last year one of my crews had a hell of a time running a traverse down through a 100 foot wide utility easements that was wildly overgrown.
Two days after they were done the utility company was out there doing maintenance and cleared the entire area.
Guys were not happy!!
We worked on a site that looked just like that down in south Jersey and we were able to do the same thing.
We could have worked our way through traditionally but the high pole with GPS worked great and saved tons of time.
We were using an RTK unit that had a cable to the controller so we had to be careful of snagging the wires but we would just walk through the brush and hand off the range poles and then snake the unit up through the top of the brush and low lying trees.
Worked like a charm
I have a 25' Hixon pole for this.
I don't use it often, but it's handy.
N
Gregg Gaffney, post: 372238, member: 1111 wrote: We worked on a site that looked just like that down in south Jersey and we were able to do the same thing.
We could have worked our way through traditionally but the high pole with GPS worked great and saved tons of time.We were using an RTK unit that had a cable to the controller so we had to be careful of snagging the wires but we would just walk through the brush and hand off the range poles and then snake the unit up through the top of the brush and low lying trees.
Worked like a charm
That is definitely the beauty of Bluetooth!
25' is up there! Nate, I am curious about your Javad. How often do you have to raise it up over brush?
Brian McEachern, post: 372242, member: 9299 wrote: That is definitely the beauty of Bluetooth!
25' is up there! Nate, I am curious about your Javad. How often do you have to raise it up over brush?
No doubt about it Brian - we since have moved on to all Bluetooth and do not miss those wires even a little bit.
Well, Brian, I'm a pragmatist.
I carry mine on a 12' hixon pole, most of the time.
I evaluate each place I want an observation on.
I'm a believer in the "great tripod in the sky".
That's an imaginary, inverted tripod, made of holes, in the obstruction, to sky view.
I'd druther get a shot in 5 mins, than in 6 mins.
If I see advantages, going higher, I do it.
I turn on the flashlight, that's on the bottom of the LS. It flashes, to let me know, when it gets a shot, etc.
So, when in woods, I go up, if there is good sky up there. Better to be done faster, than slower. I'd love to see a side by side comparison.
N
I have seen the LS go much faster, down low. My rod, fully down, is 5 ft.
So far, I have used 12' rod (my standard rod) and 16' rod (one job) I was up against some metal buildings, and being above the roof helps alot.
Many users have 8' rod as their every day rod.
The monopod, that comes with the LS, has some advantages... The LS has tilt sensors. And the wiggle of the LS, on a monopod, actually helps it some...
Good deal. Seems to me the standard pole for most gps folks around here is a fixed 2 meter and that's also what I use mostly. It's tall enough for most applications but we would probably be more productive in some areas with a taller pole.
How in the world do you guys keep such tall polls (15+ feet) level?
No level.
Plumb! Ha ha
🙂
The hixon poles are very good.
For topo shots, it does not matter.
A carefully plumbed 16' rod, getting a shot, with 0.04 error from the pole, and another 0.10' from gps, still gets you some useful data. If you add that error together, it 0.14' if it compensates, its maybe 0.08'.
Still pretty good.
Beats cutting line, traversing, and trying to get it. 2 hrs, vs 15 min.
This is a common paradigm.
Many shots, + - 0.2' is sufficient.
If you want accurate shots at 16', you can do a series of observations, rotating it 90 degrees after each shot, and average the observations. If you do 4 shots like this, you have 16 minutes invested. Then, if you have the LS, you can post process it. So, now you have more data, more confidence. You can see how far apart they are. It gives you enough data, to statisticly consider it. If it needs more data, then do it again. When ALL the shots are very close to each other, and you have screen shots with it, (screen shots are pictures of the screen at various stages of analysis) by the time you are done, you have a pretty good idea of how accurate your tie to that point is.
And you are 100% sure that bad initialize did not bite you.
It's not Kent Mc. Good, but it's a few hundredths from it.
🙂
If the pole is straight and you can hold an 8 minute bubble to say 4 minutes, then at 15 feet you may be off 0.02, which isn't bad. But you'd better be sure the bubble is calibrated and you are very steady.
gschrock, post: 372327, member: 556 wrote: Added another bubble up as high as I could see
If the pole is straight, then the bubble should read the same whether it is at the bottom, middle, or top. But I can see an advantage in having it just below eye level.
here is a shot taken at 12'. Glonas was off, so this one day job took 3 days
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I just thought you might like to see the high school that has your namesake.
Andy