Air and water temperature

Alexandre Belloni alexandre.belloni at
Fri Nov 11 19:12:07 PST 2011

On Fri, Nov 11, 2011 at 11:46:30AM +0100, Jef Driesen wrote :
> I agree with Linus that this is best done at the libdivecomputer
> level, where we know best how each model stores this kind of
> information.

I kind of expected that answer. I'd like to help there but I don't know
much about dive computers other than Suunto's. Would you have any
preference for the implementation ?

> Adding extra fields such as temperature, begin/end pressure for each
> tank, etc is already on the (long) todo list. I haven't decided
> exactly on which fields to add, but the idea is to add only those
> fields that are available (or can be calculated from profile data)
> on a wide range of dive computers AND that are useful for a general
> purpose logbook application (e.g. like subsurface, which is not tied
> to a particular brand of dive computer). This means there won't be
> support for very device specific fields like personal adjustment
> factors, decompression settings, etc. This kind of information just
> varies too wildly to cover with a common api.
> Even simply fields that appear quite generic can already be quite
> tricky. For example some dive computers store ascent rates as a
> simple value (eg. m/min), others as an index into a table (e.g. 0-5,
> 6-10, 11-15, 15+), or even just some fuzzy indication (e.g.
> slow/fast). This makes it very hard to define a single ascent rate
> representation. And there are many more examples like this.
> But I don't think this type of info is that important too have,
> because fields like ascent rate, tissue loading, etc can easily be
> calculated from the profile data. These calculated values may not
> match exactly with what you would get from the dive computer, but
> I'm not convinced that is very important. I would prefer to
> concentrate on those fields that really matters, like divetime,
> maxdepth, gasmixes, tank pressures, etc.

Yeah, I also wanted to add OTU but, I guess it is better to let it be
calculated by subsurface. But for now, if I'm not mistaken, it is not
taking into account the recovery during the surface interval.

Alexandre Belloni

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