Thanks dirk,  the numbers make sense when you know the thought process behind 
them.


________________________________________
From: Dirk Hohndel [[email protected]]
Sent: 08 December 2015 15:28
To: John Smith
Cc: Subsurface Mailing List
Subject: Re: Rounding up/down of maximum depths and other variables.

On Dec 8, 2015, at 7:07 AM, John Smith 
<[email protected]<mailto:[email protected]>> wrote:

As I am comparing data between mobile and PC version, I am starting to 
understand more about how things are calculated, but have a few queries.

By the way, these are just questions rather than any thing else....

1. Why are depths rounded up/down to the nearest integer? With normal table 
use, the maximum depth is usually taken as the depth rounded to next highest 
integer.

What else would we do? I'm not quite sure what you are asking. We should report 
11.1m as 12m? I don't think so.

2. Why are temperatures taken to the lowest value seen rather than the average 
over the whole dive - for example this:

It's a reflection of what most (?) people use the temperature value for: figure 
out what thermal protection to wear. It's also a left over from what older dive 
computers used to do: they stored just one temperature value for a dive and 
that was the lowest temperature measured (for many) or the temperature at the 
deepest spot (for some).

is recorded as a 27 degree dive, but you can see there were only a few moments 
when 27 degrees was recorded. Would an overall modal value be more 
representative?

3. And if you look at the dive list on the above grab, why do some depth values 
not get rounded whilst others do?

It's a matter of perceived precision (and certainly debatable). Showing 102.2m 
seems silly - actually, in general showing "10cm" resolution on depth is silly 
- is that your left arm, your right arm, or your toes? Yet not showing a 
decimal for single digits (6m, 7m) causes people to tell you that you are 
over-simplifying. So we compromise and show a decimal down to 20m (IIRC) and no 
decimal after that. I agree that this looks inconsistent - but I'm not sure 
what a more reasonable solution would look like.

/D

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