Fitness Outdoor GPS buying guide
GPS for runners
There are plenty of devices available for runners. These usually look like a wrist watch but use a GPS sensor like the one found in most smartphones for keeping track of your location while you run. So long as they have a good satellite lock, they can be accurate to around 5-10 ft.
What are the benefits?
Keeping track of distance run can help you put together a training regime that requires nothing more than a pair of running shoes and the open road. Most runners' GPS devices will alert them after they've travelled a set number of miles, for example, and keep track of how far and fast they've been moving.
Creating a workout
They should have a stopwatch built in as well, and the best will have a heart rate monitor and come with PC software that will help you devise a good routine. Plus, the best also come with 'ghost' runners who act as targets to beat - it's like those bikes at the gym where you have to keep up with another rider.
GPS for cyclists
There are plenty of training aids which are built to sit on your bike's handlebars. These will often come with maps installed, just like a handheld GPS, to help you navigate in areas you've not been to before.
GPS for orienteering
GPS devices often contain electronic compasses too. That way they can help you navigate even when you're out of range of a satellite. Look out for advanced handheld GPS units that also work as a barometer, so you can keep an eye on weather conditions too.
For runners' GPS systems you may not need a map. But all the big names like Garmin make training aids too, and have access to the same mapping data that in-car systems do. A top-end GPS device will also include information like altitude and map contours, so you know if there's a hill ahead.
GPS is a battery intensive application, and it's a good idea to make sure your chosen device will last a full day before you buy it. Mountain rescue groups have repeatedly warned hikers not to be absolutely reliant on GPS devices - always take a map and a compass if you're going off the beaten track as a back-up in case things go wrong.
- Geocaching: geocaching is a popular hobby that involves finding 'treasure' - markers left by other geocachers at specific GPS co-ordinates. You can find the co-ordinates of these spots on websites like www.geocaching.com, and the challenge is to find them using nothing but your device.
- GPS: Global Positioning System - a network of satellites that orbit the Earth and which transmit a signal to the ground. By cross-referencing the relative location of several of these signals, a GPS device can triangulate its position with a good level of accuracy.
- Internal memory: the amount of storage a GPS device has for map data and keeping a history of your movements.