Look at how much fun our geocaching partner is having! Thanks to Garmin for loaning us the GPS receiver too.

Geocaching is part hiking, part treasure hunting, and part technology. Using a handheld global positioning system (GPS) receiver, cachers track down hidden containers containing logbooks, little treasures, and even traveling “bugs.” In the geocaching realm, like the broader digital mapping world, Mac support had been an afterthought. These days, however, it’s possible to participate without resorting to Windows.

What you need: Handheld GPS receiver ($150 and up), MacCaching ($15, www.maccaching.com), iPod/PDA/smartphone (optional, see step 4), Geocaching.com account (basic membership is free; 
premium is $30 a year), Swag (see step 5)

1. Set Up Your Account

Create an account at www.geocaching.com to get started.

To track down a geocache, you’ve got to know its coordinates, that is, the longitude and latitude of its location on the planet. That’s the service offered at geocaching.com. From the home page, click Getting Started to create your account. Be sure to enter your home coordinates when setting up your account. Don’t know the latitude and longitude at your house? Step outside with that fancy GPS of yours and find out. 

2. Pick a Cache

This cache, located in scenic San Bruno Mountain State Park, looks promising.

From the left-hand navigation bar on geocaching.com, click Hide & Seek A Cache. Then, under the Seek A Cache heading, click Search With Google Maps. Here you can type in an address and locate all the caches in the area. We found over 60 caches within about eight miles of Mac|Life HQ.

Click a cache icon to learn details, such as difficulty and terrain ratings and cache size. The terrain rating indicates how tough it is to get there, so pick terrain that suits your physical abilities. If you’re just getting started, we suggest choosing caches with a difficulty of one or two. If it’s a one, you can stroll right up to the cache; a five and you’ll probably need to pack scuba gear or ice axes.

3. Load the Coordinates

We loaded several local geocaches into MacCaching, which will send the whole list to our GPS receiver.

You’ve found a cache or three to go hunt for, and now it’s time to get the coordinates into your GPS receiver. There are a few ways to do this. If you have a Garmin receiver, like the fancy Colorado 400 the Garmin folks were kind enough to loan us, you can click the Send To Garmin link from the cache description. Using a browser plug-in, the cache information will be loaded in a couple clicks.

We found it was easier to download the location files for our targets and drop them into the MacCaching app. From a cache detail page, click the Download LOC Waypoint File button. Drag the file you downloaded onto the MacCaching window to import it. Sort of like iTunes for geocaches, MacCaching allows you to store large numbers of geocache records and organize them into static and smart lists. Gather up a day’s worth of caching into a list, and MacCaching will send the lot of them to your receiver in one shot. 

4. Don’t Forget the Description

Here, we’re exporting geocache descriptions as notes we can read on our iPod.

Coordinates will get you close, but if you’re going to nab that cache, it’s vital to bring along the cache description. The simplest way to do that is to print the cache details from geocaching.com.

If you’d prefer to go easy on the trees, try paperless geocaching. New, high-end GPS receivers can load cache descriptions and hints directly from GPX files (an XML format for describing geocaches). Those of us with more modest receivers aren’t out of luck. Using MacCaching, cache descriptions can be saved directly to your iPod, or as a text file that you can then transfer to a PDA or your iPhone.