Trying to track down why some underwater data was several metres higher than a sump water surface, I discovered that closing loops between stations at the same depth in diving data alters the depth of surrounding data. This was not expected!
I've attached a fragment of the data which illustrates this. Without the loop closed:
Station entrance.030 is at depth -5.30
Closing the loop:
*equate Entrance.010 EntranceLoopNorth.019
where both these stations are at the same depth, but horizontally displaced (a common scenario as depths are absolute but length and compass errors accumulate in diving data), now:
Station entrance.030 is at depth -5.48
Is this a bug, or have I not understood something here?
Footleg