Tēnā koutou katoa.
On 16/01/2026 06:01, Dirk Hohndel via subsurface wrote:
I think it is a bit rich to call the diving that I actually did,
and the problems that I actually encountered 'academic'.
I apologize for calling your life academic. However, calling it a
0.1%-er problem might appear equally offensive. Among our 35+k
users, this is not an issue that people encounter.
I suspect it's more than a 0.1% problem - in Australia alone there are
two popular diving areas (Mt. Gambier and Gold Coast) that each have
1000s of dives done each year, and sit right on the border line between
two time zones (or a DST boundary for the Gold Coast). But maybe this is
only a localised Australian (and potentially Russian) problem, as for
most of the rest time zones seem to be following sovereign state
boundaries, making them less likely to be diving hotspots.
There is no way to get this right. And if you dive with multiple
dive computers (as I know you do sometimes) you'll end up with
different values and for that situation you'll simply have to
manually fix it in your dive log. I will be very very resistant to
any attempt to force timezone handling into our dive list time stamps.
Not sure how much there is to 'get right' when it comes to persisting
the time zone information if and when this is supplied by the dive
computer as part of a dive log timestamp. This could practically even be
done as 'Extra Information', and would remove the guesswork when trying
to make sense of unrealistic looking timestamps after the fact.
Re multiple dive computers: My other dive computers on the Mt. Gambier
trip did not have GPS, or time zone awareness. So they reported the dive
time in the time zone where they had last been used, which was New
Zealand time. So dive computers that track time in the form of 'whatever
time it was wherever the user last bothered to set the time' are not
helping to fix this, unless the diver is meticulous enough to add 'check
that the correct local time is set' to their pre-dive checklist.
I feel there is still some confusion on this particular point. I'm
not at all suggesting that your dive list should (by default) show
the dives you did in Japan with the time remapped to your current
local timezone. It should show them in JST (if that's what your
devices were set to) at exactly the same time it shows them now. The
only difference is we would /know/ they were in JST (and could
calculate time relative to that correctly) instead of having to guess.
I think we are on the same page here. This is about recording what
timezone a particular dive was recorded in, not about trying to be
clever with it.
Sure you do, if you write "(Somewhere in) Hawaii, 16th January 2026"
in it, then you have recorded what time zone you were in.
This may work well for Hawaii, but '(Somewhere in) Mt. Gambier' will not
narrow it down to a single time zone.
Ngā mihi
Michael Keller
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