Andy,

Fist of all I am not an expert, but have used my gps for the last couple of years, mostly for hiking, hunting that type of thing. First of all it is not a replacement for common sense and outdoor skills. I have seen people try that and if the battries die they panic. I have the etrex vista with mapping, compass the works. This is how mine works, but others may be diffrent.

The map can be very handy at times, but is not necessary depending on how you want to use it.

The compass is a handy feature as well. Esp if your non electronic one gets lost or broken. Also if your not sure you can double check your direction, magnetic declination etc.

The altimeter uses barometric pressure to determin altatud, but can be calibrated either using a known elevation marker like at airports or the gps will give you an altude that is close enough. I haven't found mine useful, but I could see its use in going through high elevations, mountains etc.

All have waypoints and I recommend setting those once in a while so if you do get lost, you can find your way back to where you were not lost and start over.

Most have track logs, again a good way to back track.


Used in cojuction with a decent map you can pin point where you are at on a map, but I recommend you dont use this only. Remember if you do that and it gets broken in a crash you are lost. Be sure to get a GPS that has multipal map datums so you can use the one that goes with your map. Otherwise you will be off any where from a few feet to a couple of miles. Not good if things are going bad.

I think a GPS is a very handy tool to double check your other skills, but not a cure all. I guess the best way to put it is don't go anywhere with a GPS you wouldnt go without one. Always always always have non electronic maps of the area if possable to use in conjuction with the GPS that have UTM markings. I hope this helps.


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John

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John