[PATCH 3/4] When merging non-overlapping dives, add surface events in between

Jef Driesen jefdriesen at telenet.be
Wed Nov 21 08:56:53 PST 2012

On 2012-11-18 19:18, Linus Torvalds wrote:
> Most of the dive computers I have access to don't do the whole 
> surface
> event thing at the beginning or the end of the dive, so when you 
> merge
> two consecutive dives, you got this odd merged dive where the diver
> spent the time in between at a depth of 1.2m or so (whatever the dive
> computer "I'm now under water" depth limit happens to be).
> Don't do that.  Add surface events at the end of the first dive to be
> merged, and the beginning of the second one, so that the time in 
> between
> dives is properly marked as being at the surface.

That's maybe something we should deal with at the libdivecomputer 
level? Maybe we should consider adding "endpoint samples" (with zero 
depth) when they are not automatically provided by the dive computer. I 
wrote some overview about that (and other sampling issues) some time 


> The logic for "time in between dives" is a bit iffy - it's "more than 
> 60
> seconds with no samples".  If somebody has dive computers with 
> samples
> more than 60 seconds apart, this will break and we may have to 
> revisit
> the logic.  But dang, that's some seriously broken sample rate.

Unfortunately, they do exist. The Suunto Solution (a very old device) 
uses a 3 min sample rate. And then there is the Oceanic variable sample 
rate, which is *really* ugly. If the depth remains constant, there are 
no samples recorded at all.


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