discrepancies on dive time

Linus Torvalds torvalds at linux-foundation.org
Mon Jul 8 09:15:58 PDT 2013

On Mon, Jul 8, 2013 at 3:18 AM, Pedro Neves <nevesdiver at gmail.com> wrote:
> I have a dive profile on the attached xml file. The dive profile data is
> around 56' long but Subsurface reports the divetime as 47'. Why is that?

Oh, subsurface ends up ignoring surface time for many things (average
depth, divetime, SAC etc).

For example, if you end up doing a weight check (deep enough to
trigger the "dive started") but then come back up and wait five
minutes for your buddies, your dive computer may say that your dive is
50 minutes long - because you have fifty minutes worth of samples -
but subsurface will say it's 45 minutes - because you were actually
diving for 45 minutes.

It's even more noticeable if you do things like divemastering the
initial OW dives, when you may stay in the water for a long time, but
spend most of it at the surface. And then you don't want that to count
as some kind of long dive.


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