Following up on my other thread on comparing my rookie survey to a recent GPS survey done by a licensed surveyor, I've done some extensive analysis, addressing many of the questions in that thread regarding Grid/Ground, Project Factors, International feet vs. US Survey Feet.
All I did ultimately was to translate my survey in X, Y, and Z to the GPS surveyor's location using his base station location (and my primary station used for astro azimuth).
Here's the overview:
Then I computed inverses from each of my four points to his, and also compared the distances and directions of the four legs. That's here:
I quizzed the surveyor on the .31' discrepancy which looks like an outlier compared to the others. I showed him my mega-redundant total Station measurements. He said: "he might have had the IMU turned off when recording one or the other of those two points and that the angle of the rover pole could contribute to an error that large". Not sure what to make of that.
I'm really not sure how good GPS can be when measuring elevations, but I've got a variance range of over a foot myself compared to his observations, so, bottom line, I'm giving myself a passing grade on the horizontal distances I measured, and maybe a D+ on Elevations. Lot's to learn still.