LOD on 4th down

[whitehat]

Concerning a measurement: If you have the privilege of working on a very well marked field (as in an artificial surface) then of course between the 20's you try to start a 1st down on a hash or yard line, then knowing if the dead ball spot has reached that hash ten yards down field you don't measure. If you start on a half yard spot it's a little trickier. The tape on the chain helps, but at best, Umpires footsteps are an imprecise science. If the covering official is on his game he will ensure the spot of the foul (even by moving his flag) is not that close either way....:-)