What is the best kind of GPS system for you? This depends on what you intend to use it for.
Garmin 12 GPS is very good. There are various models of the 12, 12XL etc. They can be found for under $150. The altimeter is usually off but once you find your position, most of the time the map tells me what my altitude is. They have a pretty decent battery life since you rarely ever use your GPS for 12 hours straight.
The vendors selling GPSunits are Garmin and Magellan, those are good brands and can meet your requirements quite well. There is a third player, Brunton (compass makers gone hi-tech). They make very reasonably priced GPS units with lots of bells and whistles. Garmin GPS records the distance travelled, speed, average speed, etc. Make sure you get good battery life and enough memory to be useful.
Mitac Mio 168 comes out well for my requirements but is more expensive, especially if you go for the tom tom mapping software too (voice directions when I'm out on my motorbike!)
Most of the functions on GPS of this sort you can get from a map. Maps on pure GPS are not as good as on a GPS/PDA but good maps for these are usually expensive. Some mountain rescue team members use PDAs with 1:25000 OS mapping data for recording search patterns etc.
You really need to look at your own plans - for instance, most backpackers use GPS to "confirm" their position, and they don't use it to set waypoints, determine compass direction, navigate, etc. Many backpackers use it as an emergency navigation tool in Utah 's deep, narrow canyons, where a map and compass can be almost useless.
One word of warning, take very seriously the statement on the front of all GPS units "Do not rely on this unit as the primary source of your navigation." It's always a good idea to have a map and compass with you when engaging in wilderness travel and use them right along with the GPS. It can actually be kind of fun to see how accurate you are with a compass and compare map routes with GPS routes to see why you ended up going the way you did.
What are the numbers on a compass for and how do you use a compass? The numbers on the compass are for degrees or headings. They will tell you what direction to proceed on. The first thing you need to do is figure out what kind of compass you have, a floating dial or a floating needle.
As to emergency contact, you could buy an expensive Iridium/satellite phone - they can get a signal just like a GPS does. They run over $1,000. It may also be possible to rent one. For real emergencies, not simply a vehicle breakdown, there is a GPS signaling device, much like ONStar (GM trademark), that can send an emergency signal. The final thing to do is to check in at the local ranger station, BLM office, forest service visitor center, etc., and see about leaving your itinerary with them, as well as a promise to check-out with them when leaving. If you don't check in, they would send someone out to check on you.
