So, I decided to compare my aging Garmin 305 with my iPhone 5 running Strave (Free version).
I'm kind of a minimalist when it comes to running, but I feel recorded metrics are important for the serious runner. Not only for gauging the day's efforts/pacing, but also to help spot a trend of over-training before it results in injury (or illness).
However, my experience with phone GPS inaccuracies/inconsistencies, combined with my minimalist desires while running, has kept me using my Garmin for 98% of workouts and leaving the phone behind.
Previous Issues with phone GPS:
Well, how to put this...."they're unreliable at best and wildly inaccurate at worst."
My previous experience running with people using iPhone 4 and iMapMyRun have left much to be desired.
The apps (on both iPhone4 and various Android devices) has painted a trend of slightly exaggerated distances when compared to known routes and Garmin waypoint data. This was generally expressed as routes that were, on average, about 60 meters short per mile.
It doesn't sound like much, but over the course of a 20mi run can add up to 1200m (3/4 of a mile).
I decided to run a familiar route for the comparison. One that I've run with both devices (albeit with slightly differing start/end points.), with just enough distance to identify any distance inconsistencies and just enough tree/building cover to see if either device was prone to recording junk data.
The run I decided to use was a 5mi loop with some minor elevation and requiring me to run in all 4 compass directions.
So, I strapped my iPhone and my 305 to the same arm (just incase) and set out.
Well, it should be no surprise that the Garmin was much easier to navigate while running. It was on my wrist vs bicep and the screen and controls are pretty amazing in direct sunlight.
I found the need to push the iPhone home button and then manipulate slide lock just to view the screen (for comparing distances at each split) became slightly annoying.
At each split, the devices appeared to be really really close. The app seemed to change within 15ft of the Garmin. This, honestly, was quite surprising.
Now, had I paid for Strava, I could have set up the same 1mi intervals as my Garmin and had the phone audibly notify me of the split, but this was just a shakedown of the GPS accuracy and I'm a poor college student (read as "cheapskate").
Over the 5mi distance both devices were amazingly close. The Garmin showed the 5mi as taking 42:59 @ an 8:35 min/mi avg. while Strava showed 42:58 @ 8:31min/mi.
The splits were as follows: