Adding -swim option about gpxconv

[oalders]

[DDvO]

Nice to hear from you.
Thank you for your feedback and the PR.
I also like the adaptation regarding MAX_SENSIBLE_SPEED for swmming and merged your PR.

[oalders]

So this depicts the smoothing done by gpxconv using the parameters set by the new swim option?

That's correct. I did turn down MAX_SENSIBLE_SPEED to 2 in this case as that makes more sense for me, but this reduced the swim distance from ~4 km to ~2km.

There are 3 buoys set up in a triangle. I turn at the buoys and my lines are usually fairly straight, so having the GPS points go off the lines adds a lot of distance that I never covered. There's one small triangle that looks to have been a bigger one which was downsized by the script, but I'm not too concerned about that. I upload my activities to Strava and they don't appear to use any kind of GPS smoothing algorithm, so your work continues to be very helpful to me. 🙏🏻

[DDvO]

So this depicts the smoothing done by gpxconv using the parameters set by the new swim option?
Very nice demonstration of its effect!

[DDvO]

I did turn down MAX_SENSIBLE_SPEED to 2 in this case as that makes more sense for me, but this reduced the swim distance from ~4 km to ~2km.

This indicates that for MAX_SENSIBLE_SPEED the value of 2 is more appropriate than 6.
I just came across some info at https://schwimmlexikon.de/schwimmgeschwindigkeit/ that
even for race swimmers the velocity over distances of more than 200 m is less than 2 m/s.
So I've adapted the constant this way.

There are 3 buoys set up in a triangle. I turn at the buoys and my lines are usually fairly straight, so having the GPS points go off the lines adds a lot of distance that I never covered. There's one small triangle that looks to have been a bigger one which was downsized by the script, but I'm not too concerned about that.

It could well be that the upper corner of that triangle got removed for other reasons, such as (apparently) a jump in elevation or a too sharp turn. The script provides diagnostics from which you could find out the actual reason.

Taking into account that even after the smoothing applied, the other lines are not as straight as they should be, I presume that summing up all lengths the total distance is still pretty correct. You likely could confirm this in case you know the circumference of the buoyo triangle.

I upload my activities to Strava and they don't appear to use any kind of GPS smoothing algorithm, so your work continues to be very helpful to me. 🙏🏻

Very pleased about this!

[oalders]

This indicates that for MAX_SENSIBLE_SPEED the value of 2 is more appropriate than 6.
I just came across some info at https://schwimmlexikon.de/schwimmgeschwindigkeit/ that
even for race swimmers the velocity over distances of more than 200 m is less than 2 m/s.
So I've adapted the constant this way.

I'm a bit confused about the units. I thought MAX_SENSIBLE_SPEED was in km/h rather than m/s? 2 m/s would be 7.2 km/h.

It could well be that the upper corner of that triangle got removed for other reasons, such as (apparently) a jump in elevation or a too sharp turn. The script provides diagnostics from which you could find out the actual reason.

Great. I will keep that in mind. I used the script again this weekend and it didn't create any smaller triangles.

Taking into account that even after the smoothing applied, the other lines are not as straight as they should be, I presume that summing up all lengths the total distance is still pretty correct. You likely could confirm this in case you know the circumference of the buoyo triangle.

The buoys are never set in exactly the same configuration week to week, but from what I can tell the results after smoothing are quite good. 😄

[DDvO]

This indicates that for MAX_SENSIBLE_SPEED the value of 2 is more appropriate than 6.
I just came across some info at https://schwimmlexikon.de/schwimmgeschwindigkeit/ that
even for race swimmers the velocity over distances of more than 200 m is less than 2 m/s.
So I've adapted the constant this way.

I'm a bit confused about the units. I thought MAX_SENSIBLE_SPEED was in km/h rather than m/s? 2 m/s would be 7.2 km/h.

Ah, right, I confused the units! Thanks for pointing this out.
So I've fixed the value of MAX_SENSIBLE_SPEED to be 7 km/h for swimming.

It could well be that the upper corner of that triangle got removed for other reasons, such as (apparently) a jump in elevation or a too sharp turn. The script provides diagnostics from which you could find out the actual reason.

Great. I will keep that in mind. I used the script again this weekend and it didn't create any smaller triangles.

Good.

Taking into account that even after the smoothing applied, the other lines are not as straight as they should be, I presume that summing up all lengths the total distance is still pretty correct. You likely could confirm this in case you know the circumference of the buoyo triangle.

The buoys are never set in exactly the same configuration week to week, but from what I can tell the results after smoothing are quite good. 😄

I see - please to hear.

[oalders]

Ah, right, I confused the units! Thanks for pointing this out.
So I've fixed the value of MAX_SENSIBLE_SPEED to be 7 km/h for swimming.

Thanks, @DDvO!