Shooting centerline of road in tough conditions

Michael

Member
We were shooting a centerline of road in a hollow with steep banks on side and limited sky view. A lot float was showing. We were using a Precise Topo profile. The centerline would be used for offsets for new ROW lines. Not trying to be too accurate maybe 3 o 4 inches. Lucky that traffic was not an problem but was taking forever. Any thoughts on on you approach this.
Thank you Mike
 

Nate The Surveyor

Well-Known Member
Paint dots. In case a car comes. You can resume.
Start very early in the morning. Sat geometry is improved. Careful attention to Mission planning.

Tall rod. And operate the LS remotely, from cell phone, with that new app.

Use 2 people. One to guard and watch for cars, and one to carry the LS.
 

Matthew D. Sibole

Well-Known Member
5PLS
Get one shot and then use the offsets white box to get the next one so you only have to get half of the shots. (That is if you do not need elevations.)
 

Nate The Surveyor

Well-Known Member
If you decide to do what Matt says, I'd suggest a good suunto compass, or Brunton, and a 100' tape.
Shoot 2 points in the wide open, and carefully record the compass brg or AZ. This gives you specific index, on declination. The built in compass in the LS is weak. +- 2 degrees.
I often just set another nail, in the same field as the base station. Then stake the base. Record the compass direction to the base. The shot description may look like this:
Set 40d xbase 239-1/4 deg AZ to base SC # 4.
This desc of xbase means extra base, in case my base has a tractor sitting over it when I need it later. So, it delivers me from moving the tractor. I use the little degrees symbol in the LS. SC means Suunto Compass. #4 means that we have 2 compasses on the job, and they have declinations vary by 1-1/2 (or whatever) degrees.
It's handy.
N
 

Michael

Member
Appreciate it Matt and Nate. Just spit balling a thought. What would trajectory tolerances be doing this in this tough environment.
 

Nate The Surveyor

Well-Known Member
Michael, if you hit it at the perfect timing, with an ATV, with trajectory, AND maintain lock, you could do some good. How long is this road? In fact, I'd suggest you try both. Get those specific shots. Then, compare it.
The gps system was originally designed for trajectory. (Missles!) It's a DoD program. Actually, it works better while in motion, than sitting still.if If/when you loose lock, stop, and wait to regain. Then continue. I'm not saying to only do this. I'm saying do both. In fact, run trajectory 2x or 3x. You won't waste much time, and you will get a greater grasp at what this does.
Please keep in mind, GPS can never completely duplicate a shot. Because the constellations are always in motion. But, it can be close. Close enough.
Again, how long is this project?
By doing both, you will gain a sense of the whole thing. You will see places you really want/need specific shots. And, where trajectory is adequate.
In the iffy places, run 2x, 2 directions.
It's hard to explain, but if you are going 5 mph, drive under a tree, loose lock, drive on past tree, regain lock, and continue, and then repeat, in opposite direction, it'll do alot.
Nate
 
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