August 2010

Well, not exactly accuracy, but rather consistency with our fellow Geocachers' GPSRs. Let's be honest in stating we really care more that our GPSR reports its location as close to the GPSR used to hide a cache than whether its accurately reporting its location based on any other system. Our system does tend to change between cache hiders (different GPSRs and methods of collecting coordinates all factor into the reporting) so its really a hard measure to gauge. This morning Drie and I hit the trail for several caches in a local park to specifically test the newly acquired Garmin Oregon 450 (currently on sale at REI for only $249.99) and the Garmin GPSmap 62st (also available from REI for $549.95) against the units we normal bring on the trail with us -- the DeLorme Earthmate PN-40 (available direct for $299.95) and the Apple iPhone 3G S (available with a 2 year AT&T contract for $99.00) -- and to get a feel for their operation. My question is simply how far will the GPSRs report the cache is once we've located the cache and assemble all four over that container. We hit caches by an experienced and practiced hider within that park, but only by that one hider in this first test. To really make this sampling significant we would need to have measured more caches by more hiders using a varied selection of GPSRs, and I someday hope to assemble such a test with roughly one dozen GPSRs. This test however simply gives us a quick insight into the performance off all four units at finding geocaches under several conditions on a clear day. We found that only once in the five caches tested did my usual Earthmate PN-40 report closest to the cache. The Oregon 450 and GPSmap 62st split the remain four caches as being closest, and by average distance the Oregon 450 performed the best.

	Oregon 450	GPSmap 62st	Earthmate PN-40	iPhone 3G S
Cache 1	13 ft	7 ft *	20 ft	56 ft
Cache 2	4 ft *	9 ft	11 ft	17 ft
Cache 3	5 ft	4 ft *	8 ft	8 ft
Cache 4	5 ft	5 ft	2 ft *	11 ft
Cache 5	9 ft *	15 ft	13 ft	12 ft
Average	7.2 ft *	8 ft	10.8 ft	20.8 ft

Overall I was very satisfied with the performance of all three handheld units, though the poor reporting of the Earthmate PN-40 was inconstant with my experience compared to the Oregon 300. The iPhone 3G S has never performed up to the level of the dedicated units but its performance has appeared to been diminished in the upgrades to iOS 4 and the Geocaching for iPhone App 4. It will likely be sometime before I am able to assemble a more complete test and hopefully we'll have newer software releases for all these units. I could likely use some help wrangling all the units so if you're in the Metro Detroit area and interested in helping us with the testing some weekends please let me know. Hopefully we'll be able to get out before the weather really turns against us.

All prices are in U.S. Dollars for purchases within the U.S.
Software Specs:
Apple iPhone 3G S: iOS 4.0.2 (8A400) with Groundspeak's Geocaching iPhone App v.4.0.1
DeLorme Earthmate PN-40: 2.6.210726
Garmin GPSmap 62st: 2.40
Garmin Oregon 450: Software 3.5, GPS 3.7

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