GPS Treasure Hunting with Your iPhone 3G

send you to the iPhone’s built-in Google Maps application, where you’ll see a red pushpin representing your chosen cache and a pulsating blue dot representing your current location. Keep moving until the blue dot and the red pushpin coincide, and you’ll be within a few meters of the cache.

From there, you’re on your own. Part of the fun of geocaching is that the technology only gets you so far: even the most exact consumer-grade GPS receivers can only fix a position to within two or three meters, and their accuracy drops further if the satellite signals are attenuated by trees or other obstructions. And if you’re looking for a small plastic box that might be hidden under a rock or a log, a circle 3 meters in radius can be a lot of ground to search.

GPS Kit on the iPhone 3GI batted .500 last weekend, when I took my iPhone, Geopher Lite, and my dog to Wompatuck State Park in Hingham, about 20 miles southeast of Boston. I didn’t realize it until I got there, but the park is built on the swampy grounds of a former munitions depot, where the U.S. Navy once assembled and stored nuclear depth charges and other scary items. The park is peppered with bunkers, roads, concrete pads, and other ruins that were never properly demolished after the depot was decommissioned in 1965. Which means there are lot of cool places to hide caches—there are about 30 of them within the park’s boundaries, according to the maps at Geocaching.com.

Out of the six geocaches I went looking for around Wompatuck, I located three. For enthusiasts: I found Ancient Ruins #2 [GCHT5Y], What Grade Are You? [GC15DYZ], and George Washington Forest II [GC19TND] and was stumped by Wompatuck Multi #3 [GCNEYP], Bunker N-9 [GC1DY93], and Triphammer Overlook [GCEB32]. I blame my own impatience, rather than Geopher, for my inability to find the last three caches; I guess they were just hidden too cleverly for me.

You don’t have to drive way out of town, like I did, to go geocaching. It’s a little harder, in cities, to find spots where muggles won’t accidentally come across a cache, but enthusiasts have hidden plenty of them in most major metropolises. My favorite Boston geocache so far is located near the Gillette razor factory on Fort Point Channel (The Best A Man Can Get [GCX7RV]). It’s a “microcache,” a bullet-sized capsule that contains only a tiny scroll—the logbook, where you’ll find my name in square #8. The capsule is attached by magnet to—well, on second thought, I won’t give away the secret. Another fun and easy-to-find Boston cache (Fort Point Cable Crossing [GCMVJ4], near the Children’s Museum) is the subject of an entire podcast recorded a few years ago by Boston.com.

If you want to go beyond geocaching and experiment with other aspects of GPS technology, there’s another excellent app at the App Store, a $9.99 program called GPS Kit, that will give your iPhone 3G many of the features of a dedicated GPSr. For instance, it shows your speed and direction of motion, has odometer and trip-meter functions, lets you save waypoints and tracks, and displays beautiful road maps and topographical maps of your current location, downloaded on the fly just like the maps in the iPhone’s Google Maps application. And unlike the very expensive maps that owners of Garmin devices and other dedicated GPS receivers must buy to make their devices work, the maps you can access using GPS Kit and other iPhone navigation apps are totally free—another huge reason why the iPhone threatens to undermine the traditional GPS industry.

Wade's GPS TrackThe track function of GPS Kit, which creates an electronic breadcrumb trail showing your movements, is particularly fun. When you’re done with a trip, GPS Kit lets you e-mail the track to yourself, and you can then view it on a Google Map or in Google Earth. At right, you can see a track I recorded using GPS Kit: it’s from my expedition last weekend to find the two Fort Point Channel caches.

TomTom, a Dutch company that specializes in automobile navigation systems, said earlier this year that it was developing an iPhone app, but there’s been no word on that front since June. Even then, the company didn’t make it clear whether its application would provide what a lot of iPhone owners have been clamoring for: audiovisual, turn-by-turn driving directions like those you can get from TomTom’s dedicated GPS devices. But I don’t think enthusiasts need to wait around to see what TomTom and the other GPS giants will do. While the iPhone doesn’t outshine the expensive, dedicated GPS devices in every detail, apps like Geopher and GPS Kit make it perfectly usable for recreational purposes—to the point that I’d question the sanity of anyone still thinking about laying down $600 or more for a handheld GPSr.

So, the next time somebody asks you what the “G” stands for in “iPhone 3G,” tell them it’s for GPS. Or better yet, geocaching.

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Author: Wade Roush

Between 2007 and 2014, I was a staff editor for Xconomy in Boston and San Francisco. Since 2008 I've been writing a weekly opinion/review column called VOX: The Voice of Xperience. (From 2008 to 2013 the column was known as World Wide Wade.) I've been writing about science and technology professionally since 1994. Before joining Xconomy in 2007, I was a staff member at MIT’s Technology Review from 2001 to 2006, serving as senior editor, San Francisco bureau chief, and executive editor of TechnologyReview.com. Before that, I was the Boston bureau reporter for Science, managing editor of supercomputing publications at NASA Ames Research Center, and Web editor at e-book pioneer NuvoMedia. I have a B.A. in the history of science from Harvard College and a PhD in the history and social study of science and technology from MIT. I've published articles in Science, Technology Review, IEEE Spectrum, Encyclopaedia Brittanica, Technology and Culture, Alaska Airlines Magazine, and World Business, and I've been a guest of NPR, CNN, CNBC, NECN, WGBH and the PBS NewsHour. I'm a frequent conference participant and enjoy opportunities to moderate panel discussions and on-stage chats. My personal site: waderoush.com My social media coordinates: Twitter: @wroush Facebook: facebook.com/wade.roush LinkedIn: linkedin.com/in/waderoush Google+ : google.com/+WadeRoush YouTube: youtube.com/wroush1967 Flickr: flickr.com/photos/wroush/ Pinterest: pinterest.com/waderoush/