Here is the scenario. Your small firm has performed many surveys in the rural area of a specific county over decades. This is a PLSS State. Once the firm adopted the technology to determine the State Plane Coordinates of every point they use, they began a cyber library of the various monuments found at PLSS corners and aliquot corners. A fairly typical survey plat turned out by said firm will show the boundaries of the subject survey, any adjacent or nearby surveys in the same section they have produced and will label some or all of the PLSS corners involved as "Not uncovered this survey"
Thus, they are holding all "old" information of theirs as perfect (without re-verification). Descriptions are written based on grid coordinates wtih no conversion to ground coordinates. Applicable section corner reports are identical to the ones produced at the time the monument was first found or set.
Is this procedure appropriate for surveys in your backyard?
Nope. It is common in a few States I work in, but I won't do it.
We have a large data base dating back to the 1960's with many points and maps tied into the state NAD83 network including PLSS points. Whenever a new job falls within surveys we have done I check a few easy points on our map and look for any other points that tie directly to the new job to make sure they are still in but I do not re-survey everything. Are you saying that you would not trust your own work after checking a few points?
As surveyor for a mid-sized city - about 20 square miles in area - I am in the process of building and maintaining a StarNet job of measurements including a network of passive control marks with ties to PLSS monuments. This allows me to readjust the network as new measurements become available. Once a good measurement is made, redundantly, to a stable monument I can't see any virtue in continuously remeasuring it again and again ad infinitum. If I was going to use these monuments in a local boundary resolution I'd want to visit them to confirm that they still exist, and that their surroundings remained unchanged. If I'm going to set new monuments in reliance upon these old ties I'd be making check shots to the old, but generally that's how I roll.
I'd be nervous about just using old coordinates due to the ever changing flavors of NAD83 we have experienced. But the measurements are mine to keep and use forever.
