someone made a comment on Kris's thread (on laying out the concrete footing) about "eyeballing it" in reference to one of the footings being off a tenth or so.
I am always "eyeballing it". The ability to "eyeball it" is one of the most valuable skills I have learned from working in the surveying field. I have caught many mistakes by standing back and "eyeballing" the pin just after setting it, or "eyeballing" the road layout before leaving the job. I have built my whole spec house (so far) using only a tape measure and a 2 foot level. I keep things straight by "eyeballing it". I have never once resorted to using a string (other than chalking lines).
In my opinion "eyeballing it" if a very important part of surveying and construction.
I measure and then estimate, as opposed to just estimate.
You're better than I when it comes to building. I have string, string levels, chalk lines, saddle templates, squares and levels, and only at that point can I build the damn thing and have one corner post out 0.16'.
I'm treating the northwest corner of the barn like the northwest corner of the township (section 6) and leave all of the error there.
I agree. The eyeball is very useful, as is the "gut". I wouldnt underestimate the pulling of the string though.
> In my opinion "eyeballing it" if a very important part of surveying and construction.
The way that I say it is the old maxim:
>It can look right and be wrong, but it can't look wrong and be right.
When I was doing construction staking I considered it part of my job to walk through the job at the end to make sure everything looked right. I don't trust that the rodman will notice one stake is out of line with 10 others because I blew something.
I used to do construction layout, in chicago.
Right ang prism, from a c/l baseline, go 315' set a lath, and then use the right ang prism, and every 100' set another lath. We'd check in and the crew chief could not believe it. I'd go 5-600' and be off a tenth. Eyeballing is an important skill.
Dunno if my eyes are that good any more, but we were faster, by having a good eyeballer!
N
We would both check the layout at the end of the day, but I think the rodman is supposed to catch a stake out of line, before you get finished. As Nate describes, you can get really good at eyeballing even long curve layouts.
I've even got a symbol for my field notes:
I have done many construction staking using a right angle prism as Nate says. A few years ago wile still an instrument man, the party chief I worked with would push the limits of the angle mirror in staking houses. On a dare from me to stake the lot corners as well as the hubs and excavation stakes, we did it on a simple 90 degree lot and it was amazingly close, that year we would only on rare occasions break out the instrument, even on curved lots, the corners were always within 0.05.
Bob