Statistics code for desktop (and soon mobile)

Sat Jan 9 02:23:50 PST 2021

Hi Berthold,

Thanks for your answer.

> I'm not sure if we currently track the average depth. I'm also not
sure it is very well defined - what about surface intervals. Dirk?

I meant average depth per dive. This is already present in the dive
information, and it's used to calculate SAC, so it should already be
defined.

> That is an interesting idea. But don't hold your breath. Currently we
are changing the rendering engine to port the statistics to mobile and
this will take some time.

I thought so, but I just wanted to plant a seed ;-)

> Note that there is a "year" filter constraint, which is quicker to use
than the general date-filter, if that is all the granularity that you need.

Thanks, I didn't realize that there is a "Year"-Filter.

Christof

On 09.01.21 00:13, Berthold Stoeger wrote:
> Hi Christof,
>
> Thank you for the detailed report. A few short comments in-line.
>
> On Freitag, 8. Jänner 2021 23:25:07 CET Christof Arnosti via subsurface wrote: 
>>   * When I select date(yearly) as base variable and buddies as data, bar
>>     charts have a yellow warning in the drop down. Why's that?
> A bar-chart is not recommended with continuous data. A histogram is preferred. 
> However, as you note, the warning icon is not a good UI element.
>
> In case of sparse data I have likewise found bar charts to be more convenient 
> than histograms. On the other hand, I see the argument that they can be 
> misleading if only a few cups of data are missing.
>
>>   * The trend line does not always appear in the scatter graph. For
>>     example, when I select date (no binning) / depth, there is no trend
>>     line, except for when I filter out very shallow depths. For water
>>     temp over date I get a trend line right away. I'm sure that's
>>     correct and there is a statistical reason for this that I'm not
>>     aware of.
> Indeed, there is a statistical test whether there is a linear regression. 
> Willem knows more.
>
>>   * When I select Buddies over Date(yearly), and then grouped vertical
>>     bar chart, the bars are oddly spaced. I suspect that for every buddy
>>     there is a bar every year, even if the number is zero. This might
>>     make sense in some cases (for example water temperature), but in the
>>     buddy case it looks weird. Maybe add some "don't show empty bars"
>>     option for the grouped bar charts?
> I'm not an expert in charts, but I think that this is how grouped bar charts 
> should be done(?). In the case of sparse data a stacked chart is probably 
> preferred.
>
>>   * Is there some Export functionality planned? For example simple image
>>     export of the graph?
> Not yet.
>
>>   * For me the Filter GUI seems a bit unintuitive. When there is no
>>     constraint present, it's not very obvious that constraints can be
>>     added (the button is in an odd place). A change to make it more
>>     obvious could be to add a "Constraints" heading below the fulltext
>>     search, and move the button there? And maybe also display a "No
>>     constraints" text when no constraint is set? I really like the
>>     "Filter sets" functionality!
> Yes, I also noticed that - especially in the German translation - the filter 
> is quite inaccessible.
>
>>   * What I didn't find was an "Average depth" variable, this would maybe
>>     also be interesting to add.
> I'm not sure if we currently track the average depth. I'm also not sure it is 
> very well defined - what about surface intervals. Dirk?
>
>>   * "Dive number" as Base Variable would maybe make sense to show
>>     changes over number of dives. This would be interesting for me since
>>     I go diving once or maybe twice a year, so when I use non-binned
>>     date as base variable, there are basically vertical lines in the
>>     scatter plot (see below).
> That is trivial to implement and seems like a good idea.
>
>> What would be really nice, but might be complicated to implement, would
>> be to have a kind of "Zoom" or "Select" possibility to add constraints.
>> For example my Depth over Date Scattergraph looks like this:
>>
>> Now to have a look at a single holiday I can add a constraint over a
>> range of dates, for example 1.1.2017 to 1.1.2018. This works fine! But
>> the cherry on top would be if I could simply drag a rectangle over the
>> points in 2017, and set the constraints like this (Sort of a "Zoom into
>> range" functionality).
> That is an interesting idea. But don't hold your breath. Currently we are 
> changing the rendering engine to port the statistics to mobile and this will 
> take some time.
>
> Note that there is a "year" filter constraint, which is quicker to use than 
> the general date-filter, if that is all the granularity that you need.
>
> Berthold
>
>> On 08.01.21 21:42, Martin de Weger via subsurface wrote:
>>> I have played with it a bit, and it looks great. I haven’t looked into
>>> it deep enough to say I actually tested it. 
>>>
>>>> Op 8 jan. 2021 om 21:33 heeft Dirk Hohndel via subsurface
>>>> <subsurface at subsurface-divelog.org> het volgende geschreven:
>>>>
>>>> 
>>>>
>>>>> On Jan 3, 2021, at 5:17 PM, Dirk Hohndel <dirk at hohndel.org
>>>>>
>>>>> <mailto:dirk at hohndel.org>> wrote:
>>>>>> On Jan 3, 2021, at 3:44 PM, Dirk Hohndel via subsurface
>>>>>> <subsurface at subsurface-divelog.org
>>>>>> <mailto:subsurface at subsurface-divelog.org>> wrote:
>>>>>>
>>>>>> Right, I didn't test the AppImage. Silly me. I'll add that to my list.
>>>>> AppImage is fixed, also Subsurface now reacts more gracefully if the
>>>>> QtCharts QML modules can't be found.
>>>>> Instead of a crash the statistics chart is simply empty. What we
>>>>> really need is a reasonable error message (or alternative disable
>>>>> the statistics entry in the menu.
>>>>> But this is at least a step in the right direction.
>>>>>
>>>>> New AppImage should appear in downloads/test in the next few minutes
>>>>> as Subsurface-v4.9.10-235-gc63994f77-x86_64.AppImage
>>>>> This one was tested on a couple of different Linux flavors...
>>>> So we have working binaries for all platforms, but we have heard
>>>> basically no feedback on the new statistics feature.
>>>> No indication that anyone has tested this, likes it, hates it, has
>>>> suggestions.
>>>>
>>>> It's really hard to develop in a vacuum. And it's a bit frustrating, too.
>>>>
>>>> I know that guilt-tripping people into doing things simply doesn't
>>>> work. Berthold, Willem, and I will continue to just work along.
>>>> But we sure would appreciate some input. Even if it is just a simple
>>>> "this is the best software ever written in the universe"...
>>>>
>>>> Thanks and have a great weekend
>>>>
>>>> /D
>>>>
>>>>
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>
>
>
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