I use a GPS as an integral part of my cycling. My friend Scott got me hooked on the technology years ago. Now there's amazing functionality available, even directional routing, for a very reasonable price. I use a Garmin eTrex Legend C. For cycling, it provides the following benefits:
- Replaces a cycling computer and thus provides a continuous readout of speed, distance, time, etc.
- Displays a complete road map along with my current position and direction
- Full directional routing such as turn here, and go for 2 miles, then turn right
- Elevation data display
- Records a complete and detailed log of my ride
Aside from being a good cycling computer, for pre-planned rides, the GPS is a great trip computer. When I have to make an unexpected turn, I can quickly glance at the map and see how to get back on my route.
I also do a lot of post-ride analysis with my track logs. I download the GPS data and lay it out on a map. I also enter my ride stats in a tracking program. On favorite rides, I like to overlay rides from different days and race myself virtually. Learn more about this in the software section.
Non-mapping GPS A very simple GPS such as the basic Garmin eTrex can be had for as little at $100. These units have a very basic feature set, but can still be used for most cycling-related functions, although it may take a little extra effort. In short, you can make a track of your intended ride using Google maps and after you download it as a GPX file, just follow the route. See the GPS software page for more details.
The best site I've found on the web for information about the Global Position System and GPS receivers is gpsinformation.net.