GPS WTF

I've been using a number of different mapping systems to record my rides and runs, but to also try to collect tracks to create a library of trail maps.

I've been using Strava, Wahoo Fitness, Trail Forks (all on my iPhone), and Garmin Connect through a Edge 520 head unit. It's somewhat surprising how different the stats are between these various services on the same short loop...


I recently did a 5 mile (+/-) trail run in Beverly Commons (Greenwood ave)...

According to the Strava app, I ran 5.5 miles and climbed 697ft:



But importing the run from my Garmin 520 into Strava , I ran 4.9 miles but climbed 786ft:



On the Garmin Connect site, the same activity says 4.9 miles but 336ft of climbing:



And then I also recorded the ride on the Trail Forks app, also on my iPhone, I apparently ran 6 miles and climbed 945ft:



And finally, recording the run through Wahoo Fitness and importing into Strava, I ran 4.5 miles and climbed 725ft:



So, in summary, I ran somewhere between 4.5 and 6 miles and climbed between 336 and 945ft.

My friend, Dan Lund, an industry expert had this to say: https://www.digitaltrends.com/outdoors/how-gps-watches-work/

What do you use?

How do you know if it's accurate?

Does it matter?

Let me know...