TUAW Review: Geocaching iPhone app

I first mentioned this app at the end of September when word leaked out that GroundSpeak, the keepers of the Geocaching.com Web site, was working on an iPhone app.

If you're not familiar with the hobby/sport/addiction that is geocaching, the concept is very simple -- people go out and hide caches in the great outdoors, use a GPS receiver to find the coordinates of the hide, then post the cache on the Geocaching.com Web site. Cachers go to the Web site, search for caches that are near their present location, and then use their GPS receivers to find the approximate location of the cache. Once they're done bushwhacking and find the cache, they sign the logbook, take and place trade items, and then log the find on the Web site.

A week after I acquired my iPhone 3G, I wrote a post talking about how to use the built-in GPS receiver and Mobile Safari to "do" geocaching. While the method works well, I was waiting and hoping for a much better way to geocache with the iPhone 3G. With the recent release of Geocaching for iPhone, it's time to see if that better way is finally here. Read on for more details!

To give Geocaching a workout, I decided to try the app while I was on a business trip in Sacramento, California last week. I love to go geocaching in cities that I'm visiting, since it's a great break from doing work and I usually get to know some more about the city and its history.

The application icon for the app is your first indication that this is the official Geocaching.com app, as it uses the four-color Geocaching logo. Launching the app shows you a nice trail scene as well as the standard Geocaching.com disclaimer, and you're asked if you wish to let the app find your location (see below left). Since you're usually going to be going out of your way to find local caches, you'll most likely give the app the OK to get the location from your iPhone's GPS. The next screen (below right) provides fields for searching for caches by postal code, address, or the special Geocaching.com GC code. You can also tap the "Search for Nearby Geocaches" button to find the nearest caches to your location.

A list of geocaches near your current location appears on your screen (see below left). The current version (1.1.1) of the app now gives you a filtered list that does not show any caches that you've already found. To do this, you need to set your Geocaching.com user name and password in the app settings page (see below right).

The list shows a surprising amount of information for each cache. The icon on the left side of the search results indicates the type of cache, most being "traditional" caches with a little plastic container icon. The difficulty and terrain are listed as a number from 1 to 5, with a 5/5 being the most difficult type of cache to find, in mountainous or dangerous terrain.

Groundspeak, the company that runs Geocaching.com, assigns each cache a unique code beginning with the letters GC. That code is important as a unique key for the cache, so it's included in the list. Finally, the distance and direction to the cache is listed.

Tapping on a cache entry in the list opens up a detail page (see screenshot below). This page shows the latitude and longitude of the cache and the same difficulty and terrain information, along with links to a description, recent logs, and a hint. The description will tell you something about the cache or historical information about the area in which the cache is hidden. The logs will show when and how people found the cache, sometimes including spoiler information that make it obvious where the cache is hidden. Hints are sometimes riddles that make it easier to find the cache, if you can figure out the correct answer to the riddle.

Tapping the Map button takes you out of the Geocaching app and opens Google Maps. A red pin indicates where the cache is located, and the traditional blue pin and pulsating circle show your present location. I often use the Directions feature of Google Maps to find out how to drive or to a location near a cache.I find it annoying that I am taken out of the Geocaching app and have to launch it again to get back to the cache information. It would be preferable if the app used its own browser.

The Navigate button opens a compass screen with a red pointer aimed at the cache location. Your current heading, the distance to the cache, your ground speed, and the accuracy of the GPS location are all displayed on the screen. The pointer can be helpful in triangulating the position of the cache, as GPS accuracy can sometimes be off and by walking around, you can get a better idea of where the cache is actually hidden.

How does this all work in practice?

If you're in a city or in a wooded area, you can pretty much forget about getting an accurate location. Where I was looking for the cache in Sacramento, there were both tall buildings and trees that were in the process of dropping their leaves. According to the Geocaching app, the best accuracy I was getting was about 156 feet! I decided to try again with a cache located in an area with a much less obstructed view of the GPS satellite constellation.

The second cache was near my home in Colorado. The leaves have dropped here, and the sky view is unimpeded by tall buildings. I used the navigate mode to get a red arrow pointer showing me how to get to the cache, and it did an excellent job of getting me to within about 20 feet of the cache (see screenshot below). However, the arrow was confusing me as it was whipping around the points of the compass, so I switched to the Google Maps view. Here I was able to see two pins -- a flashing blue one that indicated my location, with a blue ring around it indicating the possible area I was in -- and a red one for the location. With the Google Maps aerial view enabled, I could even see the trees near the cache location.

If you're not sure if the area where you're caching has a good view of the sky, I suggest trying a simple test -- walk around the area with Google Maps pulled up. If your "blue pin" is consistently keeping up with your walk, your accuracy is probably pretty good. If it is the blue pin is a block away and just sitting in one place, or if it jumps around the map, then you're out of luck and should either use a much more accurate GPS receiver or find another location to do your caching.

One more thing that Geocaching for iPhone can do is let you find the status of Trackable Items (see below). These are specially tagged items such as geocoins and travel bugs that are left in caches for others to grab and move to other caches.

This version of Geocaching is limited in what it can accomplish. I'd love to be able to claim my caches when I find them, instead of having to go back to my computer to log into Geocaching.com and do the deed. It would be cool to be able to use the iPhone's camera to add photos to the cache log on the Geocaching website.

Should a hard-core geocacher give up his or her dedicated GPS receiver and move to an iPhone? No. I don't think the accuracy of the GPS location is as good as some of the WAAS (Wide Area Augmentation System) enabled GPS receivers that you can buy from Garmin, Magellan, and TomTom. With most "real" GPS receivers, I find myself being able to find caches much faster. I think the iPhone is getting me in the general area, but not with enough accuracy to rmake my hunt much easier.

Between my comments about what Geocaching for iPhone needs and about the accuracy of the iPhone GPS, you might think that I'm totally dismissing the iPhone and this app as a geocaching solution. I'm not. I feel that it's a good solution, and it can only get better as the app is updated with new features and the iPhone gets even better location accuracy in the future.

I'd love to hear what other iPhone-toting geocachers are using as their favorite geocaching tool. Is it an iPhone with Geocaching for iPhone or another app, or do you prefer to use a separate GPS receiver. Leave a comment below.