Altimeter watches

One small note about GPS's (anyone please correct me if I'm wrong) is that a typical hand-held GPS altitude, including the high-sensitive-antenna models, is typically only accurate vertically to within 30 metres. ie. They're far more accurate horizontally than vertically. This is at least part of the reason why some of the higher spec hand-held GPS devices include barometric altimeters. It's still necessary to calibrate them, but a good barometric altimeter in consistent weather can easily be accurate to within a metre or so. Of course if you have a GPS giving you a precise horizontal point on a map anyway, knowing the precise elevation might be less useful. On occasion it can still be very handy, though, like if you're in a place with a few steep areas. Also in some environments, pulling out a GPS just makes you look less cool. I've been glared at on occasion and had to explain that I've honestly only pulled out my GPS because it has a good barometric altimeter, and I'm really not cheating more than anyone else. :)

Sounds likely. Recall a trapline down the catlins river averaging 40m below sea level despite having the high sensitivity gps and a pdop of 5m. Caught a few too...