Imagine the Earth as a grid, an immense matrix of points that map each location -- each house, each tree, each grassy knoll -- and give each point a unique numerical value based on longitude and latitude. Imagine that you are looking down at this grid, maybe from somewhere near that puffy cumulus cloud floating up there in the sky, and looking down at me standing on a rock overlooking the Pacific Ocean: You would see that my exact numerical value at the moment is N 370 54.55 W 1220 37.61.
I am, however, supposed to be at N 370 54.637 W 1220 37.52. It would appear from your vantage point above me that I am really almost where I need to be, mere decimal points away -- a distance equal, as the crow flies, to just 100 or so yards. Unfortunately for me, down here on the solid ground, those few decimal points lead to the bottom of an extremely steep hill, down to which there is no apparent path.
And in the game I'm playing, those decimal points really, really matter.
On May 1 of this year, President Clinton signed a bill that brought an end to the practice of Selective Availability for public GPS (or Global Positioning System), a military-run location-finding system that uses satellites to precisely map that grid. For years, GPS users were resigned to the fact that their nifty hand-held GPS devices weren't particularly accurate: The U.S. military regularly degraded the signal in order to prevent data from getting into enemy hands. But in May, the military finally decided to give 100 percent accurate positioning to the public, and suddenly GPS systems that had been accurate only to within 300 feet could place your exact position to within 30 feet.
On that day, a game called "geocaching" was born. And that's why I'm here, standing on this mountain overlooking the sea, listening to the wind in the tall grasses and watching the hawks circle overhead and the silvery waves break far down below me, wondering just how I'm going to make it down this hill without breaking an ankle. If I can do it, treasure awaits.
The concept of geocaching is really quite simple: Someone hides a "stash" -- usually a large Tupperware container filled with assorted goodies -- in an interesting, out-of-the-way place, and records the exact coordinates with a GPS device. Those coordinates, along with a few helpful hints, are posted to the geocaching Web site. The stash seekers then use their GPS systems to find the treasure. Each person who locates the stash adds an entry to the included log book, takes one of those goodies, replaces it with one of their own, and then re-hides the container.
The fact that this is harder than it sounds is one I am learning as I gaze over the precipice. The directions for the stash that I am seeking -- the Firestone Stash, it's called -- were posted in October with a note that said, "Today I placed the first stash in the San Francisco Bay Area. I have named it 'Firestone' for reasons that will become evident to anyone that finds the site. Look in the trunk for the goods."
The map on the Web site pinpointed the stash somewhere in the middle of Mount Tamalpais State Park and so, with a GPS hand-held device in my lap, I had driven slowly back and forth until I found what seemed to be the parking space with the closest GPS coordinates.
What GPS devices can't tell you is that geocaching is as much about the route as the location. And so I begin half-sliding, half-climbing my way down the hill, all the while keeping an eye out for what I'm guessing, based on the "Firestone" and "trunk" clues, will be an abandoned car.
And I'm paying such close attention to the coordinates on my GPS receiver, watching as each step ticks me one digit closer to my destination (and marking, as well, the time and distance that I've traveled), that I don't even see it until I'm almost upon it: the rusted carcass of an ancient car, upside down and resting against the tree, legacy of a long-ago accident. Decades ago, at least, someone probably died here when they took a curve too fast and hurtled down the hill. Eureka.
I pry up a weather-beaten metal panel in the back of the car and find the Tupperware box. Inside the box: two wilderness books, a bag of Funyuns, four stamps, Almay sunblock, a pack of AA batteries, a painted wooden fish, a cloisonni bracelet, a key, a sewing kit, a hiking map of Mount Tamalpais and a bottle of water.
Of more interest is the log book, which includes about 20 entries from visitors (some of whom stumbled across the stash unintentionally). "Humans are strange and wonderful" says one hiker, who also uses the space to shill his band, the Radiant Radishes. "You should be looking for natural food to eat from indigenous plants," writes another. "Survival will not depend on your G.P.S." And my favorite: "In our unemployed state we went hiking on the coastal trail, and found this treasure. We have left behind the keys to our failed dot-com. Hopefully they will help someone. Cheers."
I take the hiking map, leave a can of Pringles and use the map to find a more practical way back up the mountain to my car. Driving out of the park on the steep and winding road leading back to San Francisco, I pass a cavalcade of police cars and fire engines. The edge of the road has been marked off with crime-scene tape and the authorities are peering down over the edge of the cliff. I wonder whether another driver plummeted over the edge and think guiltily about the processed salty snacks I just left behind to mark some long-dead victims' fiery grave.
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To some, geocaching will seem like no more than a bunch of gadget nuts hunting for each other's junk, but that doesn't do justice to the poetry of the process. Geocaching is like sending a love letter to the world, a secret place, vista, a favorite hike or a secret cave that the stasher shares with those who "get it." The coordinates on the GPS receiver are merely markers of someone else's memories, offered up anonymously to the strangers who care to follow.
"You're creating an experience for someone," explains Jeremy Irish, the webmaster of Geocaching.com. "Instead of having a newsgroup, you are actually going to a location and sharing a little bit of yourself, your character, through some idea or object that you put in a cache."
Or, as Andy Solomon, a 24-year-old Manhattanite geocacher puts it, "What people have in their stash and what they leave behind reflect their personality a little bit. But it's not at all about what's in the stash -- it's about the whole process, about finding it."
Geocaching was invented by Dave Ulmer, an engineering consultant living in Oregon and a self-confessed gadget lover who brainstormed the idea on the day Selective Availability was turned off. "I figured that if accuracy is such a big deal, there ought to be a totally new use for GPS, something you absolutely couldn't have done before," he says.
Geocaching made its debut on May 3, when Ulmer hid a stash -- a few mapping CD-ROMs, a slingshot, a can of beans and a book -- and posted the concept and coordinates to a mailing list for GPS users. Within a month, dozens of people had joined in the fun. When Ulmer found that he didn't have time to coordinate the burgeoning movement, Irish took over and launched the Web site. Six months later, the site's home page lists more than 180 stashes in 14 countries (it's particularly popular in Australia), and Irish guesses that well over 6,000 people have participated in the game. The numbers are growing exponentially.
Geocaching was enabled by GPS, but the concept stretches back to the 19th century and a British orienteering sport called letterboxing. Letterboxers hide a container with a unique rubber stamp inside and then offer up clues to its location -- coordinates, or perhaps a cryptic, coded message. Treasure seekers navigate only with a compass, and instead of finding CDs, bouncy balls, books or Funyuns, they carry a passbook in which they collect stamps. Geocaching is really the brashly technological American cousin of a decorous and refined European invention.
"We are very goal-oriented people -- maybe it's American -- we like to explore, and it plays on that," says Irish. Last weekend, he says, he hiked four miles out to a cache hidden in an abandoned ghost town. "It's like Indiana Jones without the boulders and restless natives. You're going out and finding something and it's relatively safe."
Or, at least, it's been relatively safe so far. Geocaching is a utopian sport, grounded on the notion that people are honest. Every cache includes a set of instructions that beg: "If you find this container by accident, please do not move it. Please do not steal everything and/or vandalize the container." For the most part, those who stumble across the caches have obeyed the rules and left things as they found them; only three have been reported plundered. Indeed, the Firestone stash was full of lovely messages from hikers who found it accidentally and were so impressed by the idea that they added to the stash without taking anything at all.
Can it last? The cynic in me thinks that it's just a matter of time before some malicious malcontent uses the system to plant a booby trap, or stuffs a cache with a dead animal or leaves behind a stink bomb. Imagine a serial killer using the geocaching game to toy with unsuspecting hikers. "A body part in each location, that would be great press," Irish laughs good-naturedly. In our crime-ridden 21st century, a game that counts on the innate goodness of man would seem to be merely tempting fate.
For the time being, though, geocaching remains a friendly and even faceless sport. Ulmer says he hasn't met a single geocacher in the flesh, though he's communicated with many online. In that sense, geocaching is a strange amalgamation of the virtual world and the real world: the anonymity of the Net crossed with the innate physicality of GPS, a game that is at once both ephemeral and earthy.
And so, I've just planted my first geocaching stash, in a secret place that has always been one of my favorite ruminative spots in San Francisco, and filled it with odds and ends from my life. In a few months time, I'm guessing, the entire stash will probably have changed three times over, and I'll have to return to see what's been left behind. Happy hunting.