If you see a handful of people at a Des Moines area trailhead peering down at what looks like a PDA and chatting excitedly about “waypoints” and “caches,” you might have stumbled upon a group of geocachers. Chances are they’re eager to be FTF (first to find) a cache, and may even be on a CITO (cache in, trash out) mission to clean up the area. But don’t worry. Geocachers are a friendly bunch, generally, and most would be glad to share their sport — and lingo — with you.

For the uninitiated, geocaching (pronounced geo-cashing) is a sport in which participants use a global positioning satellite unit to locate caches — usually waterproof gallon containers holding a logbook and trinkets for trading — using GPS coordinates, or waypoints, that are listed on www.geocaching.com.

“It’s kind of like those games you played when you were a kid, when you hide treasure and then go find it,” said Susan Weddell of Des Moines. During her first geocaching experience a few weeks ago, she found two caches in Water Works Park. It was so much fun that she went on eBay to buy a used GPS unit.

“It’s just a fun thing to do, and I found there were all these people out doing this,” she said. “It’s something new.”

Originally developed for the U.S. military, the GPS system consists of a group of satellites that allow users to pinpoint their location anywhere in the world by using hand-held devices that can range in cost from $100 to $1,000 and up.

Initially, a slight error was introduced that only military users could override, to give the military a more accurate tool than civilian users. In May 2000 the military turned off that feature, which improved the accuracy of the commercial units from about 100 meters to 10 meters. Just two days later, an Oregon man named Dave Ulmer hid the first container in the woods near Portland and posted the coordinates with a challenge for others to find it. Geocaching was born.

According to geocaching.com, there are now more than 94,000 active caches in 202 countries, with more than 70,000 new logs on cache finds being written each week by nearly 15,000 geocaching account holders.

The tech-oriented sport is just beginning to beginning to take off in Central Iowa, where organizers launched a club covering the Midwest more than two years ago. Great Plains Geocachers (www.gpgeocaching.com) now has about 170 members in 10 states, said Scott Miller, a member who coordinates geocaching events in Des Moines.   

“It’s definitely spiked a lot in the last year,” said Miller, who began geocaching two years ago. “I would say there are easily five times as many people doing it as there were two years ago.”   

Miller estimates that about 40 caches are hidden around Greater Des Moines’ parks and trail areas.   

“It seems like every time you turn around there are new ones,” he said. “And that’s part of the interesting thing about it. If people continue to hide new ones and try different variations, it never becomes boring.”   

New caches posted on the club’s Web site quickly get attention, said Jennifer Goodenow, a Waukee resident who’s also a club organizer.   

“We put a cache out in the city park that’s right behind our house,” she said. “Within 24 hours of it being posted on the Web site, we had three teams visit that cache.”   

Goodenow started geocaching more than three years ago, after seeing a feature about it on TechTV.   

“I told my husband about it, but he didn’t take to it immediately,” she said. “But then he saw the same segment about a week later and decided that would be fun. So we went out that weekend, and we’ve been doing it ever since.”   

When they started geocaching, they were among about four area teams that would monitor the geocaching Web site daily for new local caches.

“It was comical; these people had never met each other, yet they were competing to be the first ones to find these caches,” Goodenow said. “So we felt like we knew them already. Then we started organizing events where we could actually meet face to face.”

The Great Plains club periodically hosts beginner orientations; the next one is scheduled for Thursday, April 29 at 6 p.m. at the Campbell Recreation Area in Clive, meeting near the hexagon gazebo. Additional information about the “Geocaching 101 Beginner’s Trek” can be found at www.gpgeocaching.com

Variations of the sport include puzzle caching, in which riddles or clues are posted on the Web site that must be solved to find the cache. There are also “travel bugs” that can be placed in the cache and tracked on the Web site as they are moved by players from cache to cache.

As with any sport, there are rules of etiquette designed to make it enjoyable for everyone.

“Probably the biggest thing I’ve observed that gives me headaches is the trading,” Miller said. “Theoretically you should trade for like items, but people oftentimes tend to take something really nice that might be worth two or three dollars and leave some broken toy that they found in the bottom of their junk drawer. What happens is that a cache that originally had lots of good items will over time become depleted and all there is left is junk that nobody really wants.”

Food or other fragrant items are unsuitable for caches because they will either spoil, or the odor will attract animals that will pull the cache out into the open. Burying the containers is also a no-no because it causes damage to natural areas.

Another cardinal rule: re-hide the cache to leave it as you originally found it, Miller said.

Generally, geocaching is permitted within state parks, said Kevin Szcodronski, chief of state parks bureau of the Iowa Department of Natural Resources, as long as participant contact the site manager first.

“The bottom line is, we’re asking geocachers if they want to put a cache in a state park, talk to the site manager so they find a good place in the park, and that they generally limit it to no more than two or three in a park,” Szcodronski said. “If done right, it’s an additional opportunity to bring more people to our state parks, and to have some fun finding some caches.”

Polk County has a similar notification policy, Miller said. Other jurisdictions, such as Story County, have formal approval processes through which geocachers are asked to complete a form.

“The nice thing about that is once you fill out the form, generally they’ll tend to approve caches more than they disapprove them,” Miller said. “There really has to be a good reason for them to disapprove one.”