@freenico Looking at these GPS tracks, it appears like the apple software draws a smooth best-fit curve through the recorded nodes whereas Suunto simply shows the recorded nodes and connects them with straight lines. One isn’t necessarily better than the other, it is just that the smooth line is prettier whereas I actually appreciate seeing the actual nodes (to get an idea of how accurate the recording is).
As for altitude sensor, I’ve used a Spartan but I think it is different (the one with the external GPS sensor, I think it is called “sport” or “trainer” or something) and it doesn’t have an altitude sensor. My Ambit 3 Peak has it, Suunto 9 has it but other than that? I though the other ones just derive the altitude by GPS data and maybe by using acceleration data. But maybe someone else can comfirm.
Edit: This said, some Spartan nodes clearly are off of course, with some of them being outside the water. There was a discussion elsewhere as someone had also a coarse resolution GPS track when swimming and even though mine was a bit coarse, it wasn’t as bad as his. We were both using the (regular) Suunto 5. Chances are it was because of swimming style. I was crawling, he was doing a breast stroke. So that might matter too, swimming style. But if you look up that discussion (which I won’t repeat here) GPS just isn’t good under water so getting a good recording is also a matter of luck. Same goes for GPS in the mountains or in a dense city. Maybe there are ways to tweak things to get better results. That’s what experts are doing with echo (to see tissue inside your body) or sonar (to scan under water). That’s a skill on its own. But maybe it just can’t be done with GPS because you’re not transmitting the signal hence can’t play with frequencies etc. Only advice I’ve seen is, if you want better GPS reception then you need to keep the sensor out of the water. So attach it to a buoy or something.
