I've been using Garmin GPS for years, most recently the 60 series.

This weekend I downloaded an iPhone app (MotionX GPS) on an iPhone 4S. I took them out side by side for a long hike this weekend and I was very impressed with the app. I was hiking in the East Bay hills in the SF Bay Area.

First the iPhone display is light years ahead of the Garmin in terms of quality and detail. The base maps were also superior in terms of the details they offered. I purchased the Garmin Topo for Western US 24K. To use Motion X when you're out of cell phone range, you have to download area maps, but this was quick and easy to do. You go to a map and draw a circle of the area you want to download. I downloaded about 50 square miles of maps in 10 minutes via wi-fi.

Both were about the same in terms of speed in acquiring satellites and maintaining contact even canyons with tree cover. The claimed "accuracy" was about the same, but Garmin more often claimed accuracy under 20 feet, when the Motion X would be claiming 30 feet or so. At the end of the hike the Garmin said I'd covered 8.42 miles, MotionX said I'd covered 8.38. I think that variance is within the tracking errors of each. Also one time in cover the Garmin said it could not acquire a signal while the MotionX claimed it had a signal. This was very surprising to me, given the 60s reputation.

MotionX did worse at speeds, it said my high speed was 22 miles per hour, and I don't go that fast even falling down a hill. This caused my average moving speed to be a bit higher on the MotionX (2.7 vs. 2.6mph) This could also be a function of the shorter distance measurement on the MotionX.

The only downsides I can see to the iPhone as GPS at this point is that it is not as weather resistant as the Garmin and you can't swap out iPhone's batteries when in the woods (but I think 3rd party charging devices might solve the latter.)

I'm curious about others' experience with the iPhone as their GPS and recommendations for other apps.

My Garmin Oregon and my Garmin eTrex Vista HC hold a signal in dense woods, but my iPhone 3GS wouldn't. I think the antenna was degraded a bit recently, sometimes it would get inaccurate with just a light cirrus cover. My new iPhone 4S seems to hold a signal a lot better, but I haven't tried it in the woods yet. I'm mostly using Runkeeper on my iphone.

I've been using iTopoMaps and been very pleased with how it performs. As a dedicated wildlands GPS, the iPhone isn't sufficiently rugged, but as a backup or for casual use on and near marked trails, it's been great. I drop a waypoint at camp, another at the trailhead, and off we go.

(No affiliation to Apple or whoever the publisher is of iTopoMaps other than as a satisfied customer)

I'll echo your experience. I'm using MotionX GPS HD on my iPad for hiking and city walking; and MotionX Drive HD for driving. They are both superior GPS apps. I too have noticed that the iPad holds a signal better than my handheld GPS, an old Garmin eTrex. I also note the absurd Fastest Speed numbers in MotionX.

I'm jealous of your iPhone 4S! The iPad is my first iOS device but I see an iPhone in my future. I have heard that the iPad GPS is more sensitive than the iPhone's. But it would be a lot easier to take hiking!

The weather resistance is important to me, but I've been wrapping my iphone in a zip-loc bag when out and about, and it's not WATERPROOF in that setup, but it rain-tolerant.

My experience in terms of GPS signal lock, map quality, etc. is the same. I use a Topo app (can't remember name at the moment) and it works the same way - you preload a bunch of maps and it works even where there's no cell service.

I still think that the "dedicated" GPS devices are tougher, but the user interface on the Garmin and Magellan devices just can't hold a candle to the iPS user experience. Android devices are nice too.

As far as battery - there's a universe of external battery options, I have a gizmo that gives me USB ports with just AA batteries, and that works. I also have external spare batteries for the iOS gizmos in my life.

I have the iPhone 4, but no trail apps. I don't get good cell tower reception in the areas I hike.

Are you saying w/out a cell phone signal your still getting GPS accuracy to 30ft?

Or better. And iTopoMaps and MotionX let you download maps for offline use.

Thanks for this. I just may purchase the app

Yah, I had an older Garmin eTrex Vista, the Vista HC is far better. That's what the "H" is for, high sensitivity.

If you want to add a bit of weather protection to your iPhone, try the Otterbox Defender case http://www.otterbox.com/iPhone-4S-Defender-Series-Case/APL2-I4SUN,default,pd.html?dwvar_APL2-I4SUN_color=20&start=1&cgid=apple-iphone-4s-cases It adds bulk but no real weight and you can access all the functions with the case on. The screen is a bit less sensitive in the corners with it on but still usable, the rest of the screen well you wouldn't know you had it on. I haven't tried it in really bad weather yet (curse this sunny Australian weather :-) but it looks like it should be ok. You can get them in a camouflage cover, just don't drop it.

Cell data connection will let you acquire satellite faster by downloading the telemetry quickly, but has nothing to do with accuracy.

From what I hear the GPS antenna in phones are good at low latitude, but as you go north/south they run out of steam pretty fast.

I can't figure out why that would be the case. For directional satellite antennas, sure, you can only point them so low to the horizon, so if you're trying to aim at a geostationary satellite the further away from it's regular footprint you go, the worse it will work. But GPS doesn't work like that, the satellites are in medium earth orbit and cover the globe pretty evenly. GPS receiver antennas are typically either omnidirectional or are optimized for receiving signals from straight overhead.

As long as you aren't dependent on the terrestrial data network for maps, a cellphone GPS should work quite nicely anywhere on the globe. Now, with that said, I have no GPS experience outside of North America, so if there's something going on that I don't understand please let me know.

Just returned from extensive walking and navigating in a large city. I found that the latest and greatest Garmin had trouble acquiring and maintaining a signal in the urban canyons and that the iphone actually navigated better and more consistently. I bought a Mophie battery extender for my iphone as I was going through the battery so quickly. The advantage of this is that you do not have to turn off your phone or wait for it to charge up. You can use it in conjunction with your iphone battery. I did not get quite double the normal battery life of the iphone, but it was about 1 and 3/4 the normal life. It generally carried me through a full day, and I used the Garmin for those times outside the urban canyons.

In city the phones generally have advantage over GPS as they can use WPS when no satellite is available.

Be careful with that though, I've found that a non GPS signal is less than acurate. Maybe because I live in a good coverage area or have a phone with a good antanna or whatever but I hit a lot of towers right here which results in my non gps locaton having a lot of movement. I've turned off the aGPS and wifi location to keep it accurate.

You NEVER rely exclusively on technology for navigation, you have to be familiar with your routes and areas and stay oriented. I ALWAYS carry a hard copy map and maintain knowledge of my locations as I move. The technology can help in many ways, but it is an aid only. All that being said, I found the cell phone signal to be within about 150 feet of where I knew I was, while the GPS jumped around or lost signal. When trying to find a particular business or marking a waypoint, the technology is more helpful, and this was mostly impossible with the GPS.

On a side note, I would like to find the best iphone app which gives the functionality of a GPS (marking waypoints, distance to travel, navigating to a location). Any ideas out there let me know. Thanks.

I like iTopoMaps for this, not least of which because I can download quads and not be dependent on data connectivity. No affiliation.

Interesting. Which GPS receiver were you using? I have had no trouble maintaining lock with either my Garmin Nuvi or GPSMAP 60CSx. Both have the high-sensitivity receiver and the 60CSx has a very good antenna which helps.

I was using the 62st. I am more accustomed to the 60csx, and have had good luck with that as well. I was surprised at the difficulty the 62st had. But it was downtown San Francisco and some pretty tall buildings. it worked fine in areas of open sky like large intersections and lower buildings. I ended up using the two devices (which looked a bit strange to locals). I drove in with a Nuvi and had the same issues once I got into the downtown area. The signal would jump around at times or fix in a bad location a block away.

Interesting. I had a lock problem with one of the older receivers but haven't seen it with the Nuvi. I've heard others say the same regarding peeps preferring the 60 series over the 62. The 62 should have an even better receiver, but that doesn't seem to be the case.

Yes, you don't need cell sites for GPS.
TomTom iPhone is the same - works without cell reception.