"X" mark in a manhole

I see what you are

"saying" now. We always recorded the elevation for a manhole cover on the edge above the "out" invert, but we were also removing the cover for measuring the inverts.

Andy

Oh Ok! Was not sure you were talking about the x/y factor location on a manhole or the zenith value. I always reference a TBM on a manhole at north rim. Then locate it horizontal with a point number on a sketch or stationing off a set of plans. In my opinion an elevation on a manhole should be very temporary. I am heavy into construction so I have to shoot exsisting manhole rims to verify pipe sizes and inverts before construction begins.