Also, the actual definitions of the latitude lines are independent
of how the continents might be configured; they're just relative to
the orb of the earth and how it spins on its axis. Longitude is
taken relative to Greenwich Observatory in England, but I suppose if
some giant came along and carted the observatory over to Ottawa or
something, everyone would have to either renumber their longitude,
or we'd have to redefine longitude. It's important to note that the
choice of Greenwich is arbitrary... I've seen old American maps
somewhere (can't remember where) that showed longitude relative to
the dome of the Capitol in Washington. Using such a reference may
seem a bit odd, but it makes sense if you're proclaiming the E/W
extreme points of a country that straddles the Greenwich 180
longitude line. I mean, it makes sense to me to declare the
westernmost point in Alaska to be whatever is farthest out in the
Aleutian Islands, not what lies along the date line.

Adam