Things to know when you buy a GPS:

GPS devices have become inexpensive consumer electronics devices. One can be bought for under US$200, making them quite available. While it is somewhat exhilarating to think I can never be lost again!, there are a few things a future GPS owner should be aware of:
  • GPS tells you where you are. That's totally different from being a master outdoorsman. Unfortunately, the former capability may lead you to overestimate your abilities in the latter department. When planning trips, always be prepared for the possibility that your GPS could malfunction (e.g. get wet or run out of batteries). Are you prepared?
  • Once you buy a GPS you do not "pay extra" to receive the signal. There is no monthly fee. The United States Military budget pays for GPS.
  • GPS devices are signal receivers. They are not transmitters per se. However, they do contain electronics, which emit RF signals as "noise" when they operate. Some airlines do not permit use of GPS devices.
  • Mapping software is really neat. But be aware that outside major metropolitan areas, the maps can be years out of date or have large errors in geography.
  • Maps are expensive. Some maps (e.g. Mapsource) cost as much as a cheap handheld (e.g. eTrex).
  • GPS signals used to be corrupted via something called Selective Availability. This is a US Military thing, intended to reduce precision. Bill Clinton got rid of SA in May 2000, but it's always possible that it might return.
  • With a handheld or boating GPS you will probably never see accuracy better than 15 feet or so. If SA were enabled, the error would be much greater.
  • Accuracy depends on the number of satellites visible to the GPS. In a major metropolitan area, buildings can obscure a clear view of the sky. In a wooded area, trees can obstruct clear reception of satellite.
A list of features to look out for on a GPS
  • PC connectivity is a great feature. You can plug your GPS into a laptop and get real time map plotting. Or you can download a route after travelling.
  • Differential GPS or WAAS connectivity to improve accuracy
  • Mapping ability is very nice, particularly if the map memory can be upgraded/changed.