Note: This is a “classic” Interesting Thing of the Day article from over 10 years ago. It has not been edited recently, so it may contain broken links, outdated information, or other infelicities. We plan to eventually update or retire most classic articles, as time permits.

I have lived for many years what some consider a very inconsistently geeky life. In some respects, my life seems to revolve around computers and other gadgets. I have a lot of cutting-edge hardware, and I’m not just talking about my Henckels knives. Yet I have never owned a camcorder; my digital still camera is years out of date; my first-generation iPod holds a mere 5 gigabytes of music; and my only PDA, an ancient PalmPilot (from the days when they were still called that) has been gathering dust for years. Why haven’t I acquired the latest and greatest items? It’s certainly not because I don’t want them! On the one hand, what I already have serves my needs adequately (if not perfectly); and on the other hand, it perpetually seems that the ideal combination of features and price for any given gadget is just around the corner—that if I make a purchase now I’ll regret it within a few months. Unfortunately, my tech budget is too limited to permit me to indulge in new toys unless they perform crucial tasks and can be expected to last a few years.

For the same reasons, I have not yet jumped on the GPS bandwagon. GPS, the Global Positioning System, is a network of satellites that enables anyone with the necessary receiver to determine, within a few meters or so, his or her exact latitude and longitude anywhere on the planet. GPS receivers are used in navigation systems for cars, boats, and planes, among many other applications, and are becoming increasingly popular as an accessory for hikers and back-country explorers. Once a toy for the excessively rich, a respectable GPS receiver can now be had for well under US$100, and you can even buy a watch (albeit a rather chunky one) with a GPS receiver built in. It is unmistakably cool to have a Tricorder-like gizmo in your pocket that will tell you exactly where you are, maybe even showing you a full-color map on its display. But cool, feature-packed, and affordable aren’t enough for me: I have to have a reason to buy a gadget, an actual need to fill. To date, getting lost in the wilderness (or anywhere else) has not been a serious worry for me.

I’m In It for the Cache

But I may now have just the excuse I’ve been looking for: to the extent that I need recreation and exercise (a reasonable enough claim), a GPS receiver may be an absolute necessity. It is the single piece of equipment I’d need to participate in the activity known as geocaching.

Geocaching became possible in 2000, when the U.S. government eliminated a policy called Selective Availability that artificially reduced the accuracy of GPS measurements by non-military folk to a radius of about 100 meters. Once much more precision was possible for civilians, interesting new applications emerged, one of which was a modern version of a treasure hunt. The idea behind geocaching is extremely simple: hide some stuff (the cache), take note of its coordinates using your GPS receiver, publish those coordinates on the Web, and invite other people to come find it (using their own GPS equipment as a guide).

The cache is usually a watertight container holding a logbook (for finders to record their names and when they located it) and any other random trinkets the owner wishes to include—maybe even a disposable camera that finders can use to take their own pictures. Usually a cache contains nothing of tangible value; the reward is in the discovery itself, though you might get a small souvenir for your efforts. Finders often leave a memento of their own for the next geocacher who comes upon that site; in more advanced versions of the sport, a cache might contain clues that lead to yet another cache, or an object that’s intended to be relocated to the next cache the person discovers.

Hide and Seek

If a GPS receiver can indicate your exact position, it may seem as though there’s not much sport—just walk to those coordinates, pick up the box, and you’re done, right? But it’s quite a bit more involved than that. For one thing, GPS receivers still have some margin of error—you may need to search an area with a radius of up to 10 meters. For another, geocaching coordinates generally do not include altitude. A cache could be hidden on the side of a mountain, underwater, in a tree, under a rock, or somewhere inside a public building, all of which would make for a very interesting search. More importantly, knowing where something is doesn’t imply you know how to get to it; the most creative and challenging cache locations are those that require considerable planning, skill, and physical effort to reach.

In less than five years, geocaching has become an international craze: there are currently hundreds of thousands of caches hidden in more than 200 countries around the world. I was a bit surprised to find out that there’s even one hidden in a park just a few blocks from my home, in an area where I often go for walks. I would never have known about it were it not listed on a geocaching Web site, and the only way I’d be likely to find it would be to invest in a GPS receiver. This would, of course, add an entirely new dimension to my walks, and encourage me to do more of them. That qualifies as a need, doesn’t it? —Joe Kissell

More Information

The original (and largest) geocaching site on the Web is You can find lists of caches around the world, instructions, discussion forums, and all sorts of interesting information there. Be sure to read their FAQ.

I first read about geocaching in Internet-Guided Offline Recreation (IGOR): Geocaching by Mariva H. Aviram in TidBITS. Another article you may enjoy is Geocaching: High Tech Treasure Hunting at GIS Lounge. And the page Geocaching and Other GPS Games has lots of information about geocaching and related activities.

If you’re interested in geocaching as a family activity, check out Guide to Geocaching Road Trips, Geocaching Fitness and Fun, or Geocaching with Kids.

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And if you’re in the market for a GPS receiver, has a fine selection.