My Garmin Fenix 5 Is VERY Inaccurate In Measuring Short-Distance Open Water Swims.
Click images to ENLARGE.
Two Very Different GPS tracks for what is the SAME swim everyday!
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We have been at this lake for the last 11-years and my swim never varies. I start as close to head-on with the swim platform — when the water is waist deep. I then swim to the platform and back again — until I can’t swim any further because the water is too shallow. So, the top GPS track is accurate. I swim longer on the return leg — and it is possible, mainly due to wind, that my return leg is slightly ‘off course’ though I try to swim in a straight line using a marker on the beach for reference.
I have not as yet measured the distance, but I am fairly sure that the distance to/from the swim platform is more than 34 yards — per one of the readings. That would ~17 yards (51′) one-way. That would be the length of 2.5 twenty-foot boats. I know the swim is further than that.
Part of this has to be GPS accuracy. The distance here might be TOO SHORT for GPS to get a good handle. With Open Water Swimming the Fenix 5 uses GPS, the accelerometer and the gyroscope to estimate distance and movement. I noticed the other day that the distance jumped significantly after I had finished my swim and stood up.
I am not impressed.