anecdotal...after the cease fire in 1973, and the air war slowed down a bit, I had an opportunity to update some of the tattered working aids, and rebuild some of the unit's plotting boards... the 1:250000 UTM aeronautical charts were spliced together and covered with plexiglass so they could be written on with grease pencils... guess where the cartographers decided to have divergence in the charts?...zulu +8