GPS issues Open Water Swim

Track is pretty reasonable for the 945. Maps do not always align up with GPS coordinates from watches. When swimming that close to shore you also have tidal issues. Try looking at the different map views. Also look on Garmin Connect interweb.

Not that I doubt you but are you sure you are 200yds offshore, or just think you are. For example, this is my regular swim which involves swimming about 230m from the shore to a buoy before turning to swim down a line of buoys: Track is from an F6 but I do have similar tracks from a 945/

Thanks. I have gotten 3 different readings on virtually the same swim, so maybe weather is a factor. Today I had it set to GPS+GLONASS, but maybe will try just GPS. This lake swimming, so Im swimming well out beyond people's docks, etc.

Missed the bit about GPS settings. I have GPS+GLONASS on and it works well enough for me that I've not tried GPS or GPS + Gallileo. If you are not on 1s recording try setting that as the tracks are often better than when recorded with Smart recording (the default).

Im swimming well out beyond people's docks,

Two hundred yards is a long way offshore as you can see from my trace so perhaps you are not as far offshore as you think. If you're confident enough try swimming straight out and see what 100m looks like and further if you can.

The key point to understand is that maps do not always align with the GPS tracks recorded for a number of reasons so when you are close inshore you can get the track appearing on land. Note also that GPS errors will be amplified in the water too. Whereas you might expect 5m accuracy on land this will be much more when swimming.

Try setting an autolap and see where the laps line up if you have reference points. I'm lucky as I have buoys at 250m intervals. This is a 945 track. The numbers on the map represent the 250m laps. which as you can see are pretty close despite my less than accurate swimming that day- it was a bit rough and the sighting marks were difficult to see in the swell and chop.

Yes, my husband was boating nearby and said I was only 100 feet from shoreline:-) My mistake. Do you have it set to GPS or GPS+satellite?

• It has just been inconsistent; here are two other swims for the same course. One looks normal, the other and one from today, not so great.

I have GPS+GLONASS but found that in this part of the world at least, that it did not really matter too much. The tracks you have are pretty much what I can see between swims. I find it very much depends on sea state - rough or calm - and weather. And of course there's also the position of the satellites that changes from day-to-day and hour-to-hour. Lots of variables.

And changes between software versions too. But overall. I think I have more good tracks than bad. Certainly changed a lot since the first swims when there were issues keeping hold of the satellites.