> i don't understand the problem about rod visibility.
It is a minor annoyance only.
I think the problem stems from the terrain you are in in the Netherlands as compared to Louisiana, which can be like surveying in the Amazon at times. Lots of vegetation and it would often take too long to clear it out of the way as opposed to seeing an optical target through small breaks in vegetation.
That kind of closure is about what I got when I finished a job of approx. similar size. I just did not believe it. It is incredible how precise these things are.
"...and your closures will be less than 0.003 mm for 1km loops..."
Is this a typo?
A tight closure is necessary but not sufficient. I'm not arguing against digital levels. If you can always hold a tight closure, then you can believe it. But I'm never impressed by a single closure no matter how good.
You occasionally get an accidental near-perfect closure. I've run between two NGS bench marks to see if one was "replanted" when the ties didn't seem to match the data sheet. I closed 0.006 ft using a middle-grade Topcon auto level and 3-wire readings estimated to hundredths on a topo rod. Was the data that good? No way. I was hoping to get maybe 0.050 ft. The rest was the luck of the draw.
yes a typo shoul be .003 m to enter 1st order prescision