05.Other GPS functions
Caching the geography
A growing number of hikers are becoming interested in “geocaching”, where a handheld GPS is used to “hunt” points of interest either from other hikers or coordinates found online. All that’s required is a PC or Mac connection and relevant software to plug in the coordinates and download them to your GPS – then it’s simply a case of preparing for a hike and following the route to a point of interest.
All the handheld GPS models on test can be used for geocaching, although the Garmin eTrex H requires you to punch in the coordinates manually unless you purchase the cable necessary for PC or Mac connectivity.
Saving a waypoint
Saving a waypoint — such as a river crossing, interesting rock formation or even hard-to-find bookstore — is an ideal way to record any route markers or points of interest when you're out walking (they're called points of interest on car GPS units). Simply press a button or two on the unit. If you want it to record the entire journey, a tracking feature creates a snail-trail that evolves as you move. Once a track is created, you can save it as a route to use later or to guide you back to your original position.
Google Earth (http://earth.google.com) accepts latitude and longitude figures to zoom straight to any spot on earth. So you can just enter stored waypoints from your handheld GPS to show others spots along your last trek.
Some products provide the option to take the experience further; Google Earth Plus (annual subscription $20) allows you to export tracks from your GPS onto Google Earth, such as a treacherous ravine crossing in Kosciusko National park or a perhaps even more treacherous literary pub crawl in Dublin. Connect your unit to the PC, upload your route information and the complete journey will be shown on a Google Earth map for all to see.
Handheld GPS come with a basic world map, but you can't get a detailed electronic Australian topographic map without paying more.
- Some units have the DiscoverAus Topo SD map ($400), which does provide impressive contour details, accurate to 5m.
- Some units use the Tracks4Australia ($180 with 20m contour intervals).
- Some units use Topo Plus ($129 with 10m contour intervals).
Electronic topographic maps are contained on a removable flash memory card and provide very good detail on surrounding areas and contours, but the small screens of some units make it difficult to gain a wider view of the area. Higher-resolution screens provide the best readability of the compact units.
Some units claim support for additional marine navigation maps for those with a nautical bent. These give good depth information as well as details of buoys, lighthouses and anchorages.
You can also use a map program on a PC to set waypoints and routes at home before you head out, and if you want to show off what a hardy bushwalker you are, you can upload routes back to a map on a PC to show where you've been. All units we looked at can use mapping software on the PC, but while it's standard on most, it's an optional extra for some. Check before you buy.
All the units we looked at performed accurately when getting a fix on the required number of satellites, with differences ranging from around 3m to 12m. A wider range was observed when trying to calculate altitude, with some out by a significant 42m. However, it's generally more important to know where you are than how high you are.
Under a clear sky, you should expect handheld GPS units to take no longer than a minute to locate their position. However, when confronted with dense foliage, they vary in the time taken to get a fix.
While a handheld GPS provides very accurate recordings of individual waypoints and treks, we recommend carrying and learning to use a compass and paper topographical map as backup for anything longer than a short hike.