Cub Driver wrote:

The other day I flew up to Alton Bay. While over the bay, but still
flying north, I went go-to my waypoint for Hampton airport. (Not the
airport waypoint in the database, but one I programmed in, and that
puts me over the start of the 45 from the west.)

When I got up to the mouth of the bay, I turned around and followed
the bug back south. After half an hour I realized that I was west of
my expected track. Indeed I was going almost precisely south instead
of SSE.

What's more, my destination was 5,900 miles distant, and the time to
get there was 84 hours. The day was milky, so I couldn't see anything
on the horizon, so I turned SE until I came over US 4, then followed
that back to the seacoast.

When I got home, I scanned out and out on the map, to find that my
waypoint was now located in the Andes on the Argentinian side of the
Chile-Argentina border. Still, the coordinates looked very familar. On
a hunch, I changed the S to an N, and behold! The waypoint moved back
to the seacoast of New Hampshire.

What happened?

And could it happen to the waypoints in the database?

Garmin doesn't have the best interfaces. Both the -12 and -60CS that I
use seem very prone to coordinate input errors. I frequently seem to
get N/S switch problem when defining a waypoint.

Another problem could be that your GPS is not initialized properly.
There is an automatic init that takes awhile and a manual init that
requires you to tell it what state you are in. If you get impatient and
abort the init, I'll bet you can wind up with a bad location, maybe on
the wrong side of the equator.