Hand held GPS systems are a useful tool for anyone concerned in biking, camping, sailing, hiking, hunting, geocaching, or simply about any other outdoor activity.  Some of the hottest makes of handheld GPS units are Magellan, Garmin, and Lowrance.  These units can also be used in your auto with the use of a mounting bracket.  There are also mounting brackets available which allow you to use your hand held GPS unit on your cycle, ship, or bike.  Since they will probably be exposed to the elements on a regular basis it is best to get a device which is waterproof.   

There are two main types of waterproof handheld GPS unit : mapping and non-mapping.  A non mapping unit will be fine for straightforward tasks such as locating your way back to the automobile after a day hiking.  You’ll need a mapping GPS unit if you would like to map your trails or plan your walks ahead of time.  A mapping unit permits you to download maps from your PC so that you can have them with you during your travels.  You can’t do this with a non-mapping unit.   

While selecting the right water-proof handheld GPS unit you will have to give some thought to how it is going to be used.  The built in antennas on some units are better than others and you want one that may be able to pick up the satellite everywhere you travel.  Be aware that if you are in deep brush just about all GPS units will have an issue.  You can always add on an external amplified antenna that can be worn on the top of your hat or backpack if you find that you need one.  When choosing a water-proof GPS unit consider the amount of internal memory the unit has.  This will determine the number of detailed maps that it is going to be able to hold.