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Geocaching: High-Tech Hide-and-Seek

The treasures could be waiting in a white five-gallon pail or a small clear plastic container. They might be hidden under a rock, covered by bramble, at the top of a mountain, near a swamp, or buried beneath the snow. Now the question is: how to find these carefully stashed treasures.

Mesa Table geocache

Located at N 34° 0 W 112° 0, this is Boy Scout Troop 824's first cache hidden about a mile from Table Mesa Road near Phoenix, Arizona.
Photograph by Ralph Morong

Fortunately for high-tech treasure hunters, the exact longitude and latitude coordinates are posted on a website. All they need to do is get out there and find it.

Geocaching is an "entertaining adventure game for GPS users," boasts, the official GPS Cache Hunt site.

The term geocaching comes from "geo" from geography and "caching" for the act of hiding something in a secret spot. The sport is based on the use of a Global Positioning System (GPS) unit (a hand-held electric device that uses satellites to provide longitude and latitude coordinates accurate to about five to ten meters (15 to 30 feet)) and is also known as the GPS stash hunt.

Jeremy Irish, webmaster and founder, explains that the "grass roots" game started in the summer of 2000 and has grown to include caches in 45 states, Washington, D.C., and 24 countries.

Anyone with a GPS unit can be a geocacher. GPS units range in price from $100 to $1,000 depending on features, according to the geocaching website. Irish uses a Garmin eTrex, which costs about $100.

Boy Scout Troop 824 of Phoenix, Arizona, used geocaching as a "way to help teach outdoors skills" said Bob Renner, outdoors chairman of the troop. "I use it as a means of teaching some of the fundamentals of orienteering." The troop used a GPS unit, topographical map, and compass place their cache.

Renner, who has logged over 20 caches himself, said the troop wants to hunt for other caches, but for safety reasons, he prefers to know more about an area before taking the troop on any outing.

How it works

"There are two sides to this hide-and-seek game," says Irish. "First there's the hiding and then the seeking."

Finding a great location for the cache is key, states the geocaching website. "The location of a cache demonstrates the founder's [hider's] skill and possibly even daring." Irish suggests founders should give the person a reason to go there: a great view, beautiful camping spot, landmark, or unique rock formation.

Once a cache is hidden, the hiders log the coordinates of the location by using a GPS unit, then post the coordinates by visiting the geocaching website and entering the location, difficulty of the find, and some information about the terrain around the cache location, said Irish.

After the location is posted, seekers can come to the website to obtain a location of a cache. Irish recommends finding out additional information about the area and obtaining topographical maps to help with the hunt.

Rules of the Game

There only are a few simple rules to playing this hide-and-seek game. First, if you take something from a cache, leave something in return, and second, leave a message in the logbook, a small notebook that stays in the cache.

Writing in the logbook is a way for interaction among geocachers. The logbook may contain stories about the area around the as well as information about who placed it and visitors.

Maps, books, CDs, DVDs, small trinkets and toys or batteries for the GPS units might be found in a cache. Irish said he thinks the most interesting things found in the caches are something called "hitchhikers." A hitchhiker is any object that travels from one cache to another and builds a travel history. "The hitchhiker might be a Mr. Potatohead traveling west," said Irish.

Irish recommends that caches are hidden in national or state parks. If one is going to be left on private property, be sure to have the permission of the property owner. Also, when hiding a cache in a park, ask a ranger for permission. As long as the cache does not disrupt the environment, Irish said, it should be okay.

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The first geocache was hidden near Portland, Oregon by Dave Ulmer in May 2000, just a few days after President Clinton signed a bill a removing of the encryption from the U.S. Department of Defense's Global Positioning System (GPS), allowing citizens to access use the more accurate system.

Before May, civilians were only able to access a less accurate positioning system—accurate to about 100 meters. GPS satellites were first launched by the U.S. Department of Defense in the 1980s, but for nearly 20 years, the more accurate system was only available for military use.

According to Jeremy Irish, the GPS units may have a hard time determining location if you are under heavy tree cover or in an urban environment where obstruction from high buildings can block the satellites' low frequency signal. Cloud cover, however, should not be a problem.