Chads93GT wrote:Well.............when you survey downstream and end up with an uphill gradient because you didn't do backsites........ would you call that a quality survey? lol
Chad, thanks for the rude comment.
I'm not sure that you understood the scenario, but I'd like to hear you explain in greater detail how backsights would have helped me. Backsights may have helped with any singular instrument reading errors, but the error we discovered was solved by calibrating the instrument (yeah, should've done this when I got it, I know). This recurring error would have been present had we been using backsights or not. Fortunately, this particular error is easily solved after the survey is done. Were there other errors? I don't know, but I'd be happy to show you to the cave if you want to show me up.
Now, for a serious discussion, do you guys who use backsights with two sets of instruments account for your instrument errors when you force a two degree agreement between fs/bs? So, imagine that you have one clino at -2 and another at +1, that's three degrees difference when the instrument readers read the correct shot. If you're not accounting for this in your agreement, then there's a potential that your frustrated instrument readers are going to massage the numbers make it work. Seem far-fetched? I've seen it happen, on several trips.
All-in-all the difference between the ways we survey is minimal and both ways have their merits. Tools in the toolbox, as it were.
More importantly, though, I think next time I have a quick question about survey stuff I'll just go buy a copy of Dasher's cave survey book that I lost years ago. Or, just email George personally.
-Jon