Silly problem with dive sites and GPS downloading

Linus Torvalds torvalds at
Mon Sep 24 08:26:14 PDT 2018

On Mon, Sep 24, 2018 at 6:12 AM Monty Taylor <mordred at> wrote:
> Maybe at least collect the start/end GPS so we have them in the data,
> and maybe later someone will good idea for visualization?

For the Garmin Descent, the way it's currently done is that start/end
coordinates are captures as "extra data" strings, with a key of GPS1
and GPS2 respectively.

End result: the data does get saved, but only the last coordinate is
then used for the dive site.

So I agree, there's no huge hurry about this.

Looking at the actual data I do have, it does seem to be (a) more than
precise enough to warrant showing on the map and (b) not useful as a

For example, I did Blackrock in Maui as a "drift" dive (ok, so it took
an hour and a half to "drift" a few hundred meters because there was
no real current), and for that dive I got

  keyvalue "GPS1" "20.928930, -156.695058"
  keyvalue "GPS2" "20.926903, -156.696113"

which if you look at a map looks exactly right, but if you draw a line
between them it will go straight through the Sheraton Maui, because
obviously the actual dive is *around* the rock.

So I think Dirk's argument that we don't have good enough GPS location
is wrong - but it is true that it might be hard to show them sanely.

I think the Garmin Connect app showed the locations as a red and a
green marker. I'm not sure that's great either.


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