Pt 15383 is a routine topo check shot on a 5/8" iron rod using the AP20 tilt sensor and GRZ4 360° prism. No special care was taken other than that typical for a topo point shot. Pt 16473 is on the same point, but with a carefully levelled up and bipod braced rod, same prism, no AP20. Separate days. Separate resected instrument positions using the same 3 control points. Leica does not recommend using the AP20 for boundary point ties, nor the GRZ4, but these results are not unusual.
Count me an evangelist for both resection and for the tilt sensing.
I love my AP20, but I'm still kind of old school on turning angle to monuments. The main exception being points where you can't get vertical were the tilt is a game changer. It has to be accurate than shooting a couple of offset hubs.
Somewhere I have a copy of a white paper that says the AP20 is more precise than the bubble when the pole is withing 5 degrees of plumb.
I wish you could take a 2 face shot with the AP20. The 2 face always gives me a warm fuzzy feeing with regards to vertical on layout jobs.
I love my AP20, but I'm still kind of old school on turning angle to monuments.
So am I. At least I always have been. But I just can't ignore proven results.
Very nice but way too expensive for me. I have switched to 8' bubbles in my bdy rods instead of the standard 40' bubbles. Same bubbles as the ones in my tribrachs and my bdy shots will repeat 0.015'H and V using bipods.
way too expensive for me
An investment, to be sure. And maybe for certain kinds of business model it won't pay off quickly. But I think that, in time, it is going to be seen as a must have. It speeds up topo collection in a really big way, for example.
In my time in this business things like CAD, total stations, electronic data collection, GPS, automatic target tracking, & robotics have all taken their turn being introduced, called too expensive, and eventually become ubiquitous. So it will be with tilt sensing.
I would agree that the AP20 is a little overkill for boundary work. Like I said, I still turn 3 sets to monuments. But for topo and layout, the bulk of my work, the extra $11k was well worth it. Try doing this with an 8' bubble. The rod is not just setting on the lift, I'm laying out saw cut lines on the wall. Given the lack of access (Interstate 84 and active rail lines) I'm not sure how I would have done this prior to the AP20
Does it still cost $13,000??
I got one for under $7k total, including the mated rod and batteries. A second one ran under $10k. You have to wait for the deals. As a government agency I am able to get a discount, but you definitely should be able to come in well under $13k if you are careful.