Best profile for locating creeks etc.

Just wanted to see what profile set ups that you all are using to quickly locate creeks, streams, other things that only require 2'-4' horizontal accuracy.
 

Shawn Billings

Shawn Billings
5PLS
A bad fix in a tough environment could easily exceed your 2-4' requirement. I typically use the boundary profile if it counts. It seems like (and I could be wrong) that DPOS with a few minutes of observations, even with a bad fix keeps the points within about the range you're talking about, if that helps. I might relax my personal 180 second rule to looking for fixes with 120 seconds because I think fixes that are bad that repeat after 120 seconds will typically be within the range your talking about.
 

Nate The Surveyor

Well-Known Member
Time of day is critical. Do it when there are tons of sats up.
If it's not too obstructed, and needs high density, (lots of curves, close to each other) try trajectory. If it is not high density, do full 200 seconds with verify. It's not the hundredths you want from that. It's the time span.
GPS is like dist/dist int. If you allow some time on each point, it gives the sats time to move, effectively confirming the shot.
You might try tying flagging on a pocket load of stones. Each place you take an observation, drop a flag stone. Then, do a lower time observation on each stone. Maybe 3 clicks, over 60 seconds, BUT,
run the creek 3x.
If I ran it like this, and got 3 clicks, over 60 seconds, on each point, and re ran it, I'd probably stake the prev run, on the second run, and most of the shots would agree by some .4' or so. Then, those that did Not agree would need a 3rd run.
I've been playing with trajectory, to survey c/L roads. In obstructed areas. At around 5mph. Run it 3x. It's amazing how it's ability improves when in constant motion. And, by running it 3x, (or 4 x) it fills in the holes, via different times of day.
There is a lot to learn, about trajectory.
Play with it, on an obstructed road, that has verified c/L shots. You will see what I mean.
N
 

Steve Douty

Well-Known Member
Nate suggested "tying flagging on stones". Back before toilet paper became a scarce commodity; I would use toilet paper for this type of exercise. The paper doesn't disturb the neighborhood, it doesn't harm the wildlife or farm animals, it disintegrates after the first dew falls, and it works better than flagging if I have a sudden need. ;-}
 
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