This Boston Globe story has a nice introduction to GPS for hikers.

A map and compass may be so yesterday, but Ouellette and O’Bannon advise hikers never to rely exclusively on their GPS units. For starters, human error can be a factor in basic navigation. And, just like a cellphone, a GPS unit may fail to get the best signals, or malfunction, or run out of juice.

The two recommend that hikers use common sense and have a general knowledge of a region’s terrain. Their advice includes telling people of trip plans, wearing appropriate footwear and clothing, carrying basic supplies and water, and packing a map.

Holding up her own sleek GPS unit during the GPS 101 class, O’Bannon cautioned: ”These turn into colorful plastic rocks if you run out of batteries.”

I confess to occasional bouts of GPS lust but I never end up buying one — that way I’ll always have something on my “I’m gonna get one of them someday” list.