"David W" wrote:
"Aircraft ... are using a map optimised to the GPS system and this is
the key point which seems to be passing you by."

Nonesense. Aircraft that are equipped with GPS use the same charts that
non-GPS aircraft use.

The FAA has a pretty good introduction to GPS as use in aviation in the
Airman's Information Manual. The section you want is
http://www.faa.gov/ATpubs/AIM/Chap1/aim0101.html#1-1-19. If that doesn't
get you direct to the right paragraph, search for "1-1-19. Global
Positioning System (GPS)".