When I worked in a boatyard on Puget Sound (NW US/Canada) GPS was just
getting going as a viable boat tool and many fancy race yachts we worked on
had them interfaced with pretty powerful computer programs for performance.
Cool stuff, but some dummies would take out the charts and being lazy,
program their autopilots using the location marked on the chart for the
"center-channel marker" bouy.  Big huge steel tubs with a derrick on top,
weigh about 15tons...Then these "sailors" would go below, leaving the
autopilot to get wet in the rain....until they would center-punch the buoy
and smash in the bow of their boat....Very accurate navigating tool.

  I also had a garmin hand held mounted on my dirt bike in Baja, because the
back country there is pretty "free-style"..Once a dirt track get bumpy..they
just go overland on a smoother route..roads everywhere..And of course, no
signs or people to ask.
  We did a fun fall adventure using the GPS and some references off the
internet to explore around the desert SW and find all kinds of hot springs.
Punch in the co ordinates and ride cross the desert or through the hills
till you reached the waypoint..a good 'excuse' to play on the dirtbikes.
Looking for hotsprings try "Soak-net" or the USGS hotsprings (google)  Some
sites gave the GPS location, rate of flow, temperature of the water, and the
condition of the surrounding area...
  I have one on my bicycle now, as small as a wired computer/speedo but
accurate to within a foot or two and easily swapped between rides.  Another
Garmin..
  Don Hanson