Statistics Reloaded.

Willem Ferguson willemferguson at zoology.up.ac.za
Thu Jul 6 23:57:01 PDT 2017


On 06/07/2017 22:44, Davide DB wrote:

Hi guys

Do you remember I sketched tons mockups for statistics maybe two years ago?

On 6 July 2017 at 22:18, Tomaz Canabrava <tcanabrava at kde.org>
<tcanabrava at kde.org> wrote:

Willem,


Thanks for your feedback, I'll play more with this on the weekend. I do
believe that your ideas are nice and I'll experiment with them. If you want
I can give you my branch for you to test and experiment too.

Actually, considering that I'm by no means a good math person, do you mind
to create mockups for all possible statistics that you can think Subsurface
should provide?

This will help me a lot.

Tomaz

Tomaz, Davide,

I think the statistics on the current statistics tab are probably those
that would mostly be looked at. There are two types of display that one
would probably like:

1) Summary information for a selected number of trips or time periods. This
is exactly what you proposed in your mail: A number of bars indicating
min/mean/max for each trip or time period.

2) More detailed information for a specific trip, dive site or period. This
assumes one can select the trip, dive site or period. That could be done
from the dive list. In this respect I like Davide's idea of using the
filter tool to select some of the dives. The information could be displayed
as a histogram/bar chart as Davide suggested. For instance, show a bar
histogram of dive depth for a particular group of dives; or a histogram of
SAC for a particular period.

We need to think about the most common criteria that a diver would require
for statistics. I think these are probably:

a) Start date and end date (a bit more flexible than just selecting
calendar year) - this can currently be done by selecting from the dive list
b) Dive site(s) - this could currently be done from the filter tool.
c) Trip(s) - This could currently be done by selecting from the dive list
d) Depth range - This cannot easily be done at present. e.g. SAC for
different dive depths.
e) Davide suggested Run time - This cannot be done at present., e.g. Depth
for different run times.

So, the ease of selection of dives to be analysed is just as important as
the statistics graphs shown for these dives. A starting point for selection
would be to show statistics for the currently selected dives in the dive
list, either selected by hand on the dive list or through the filter tool.
But Davide's proposal at
http://i.imgur.com/6d1eF4N.png
is compelling. He used the current filter tool and added three more items
for filtering: date, depth and dive duration.

The question is: how should one, in addition, select the item to be
analysed (Depth, Duration, Temperature,SAC)? Davide solves that by using
tabs on the Info Panel. The trick is to implement something that does not
congest of clog the visual display. The current desktop display is already
pretty full, so showing a selection space-efficiently is a challenge. If
this applies to the desktop, then there are even more challenges on the
mobile version.

The biggest impediment to statistics on the mobile version is the inability
to select or filter dives. This will probably only become realistic once we
can collapse dive trips on the mobile dive list because there are optimised
tools for doing list selection in the mobile environment. In fact, we are
already doing that when, on mobile, we select the already-downloaded dives
to be added to the dive list.

I would strongly support the principle of doing the statistics in QML
because that reduces duplication of development.

After a long and meandering argument, here are my specific suggestions:

1) The current item Yearly Statistics in the View Main Menu item should be
the primary way of obtaining min/mean/max graphs. Currently this shows
statistics for all 4 the variables: depth, duration, SAC and temperature.
The default display could be depth, with an on-panel radio button to select
which of the 4 variables needs display. Alternatively Davide's idea of tabs
on the same panel. BUT: this panel should present min/mean/max statistics
only for the dives that are selected in the dive list. If no dives are
selected, then all dives are analysed.

2) Remove the current Statistics tab in the Dive Notes panel of a dive
because these data do not pertain to the specific dive being shown at the
time: it pertains to the dive list. Under View in the Main Menu, add
another item Detailed Statistics, which allows histograms for specific
variables for the selected dives in the dive list. If no dives are
selected, then all dives are analysed. There is a need to select which of
depth, duration, SAC and temperature should be shown (probably depth by
default, with either radio buttons or tabs to choose between variables).

3) Implement Davide's idea of adding two more items to the filter tool:
dates, and depth. I am not convinced that a filter for dive duration will
be extremely useful. It would need additional screen space in an
already-congested area.

So it turns out that for efficient statistics rendering, the main work is
actually not in generating statistics and graphics, but in generating ways
to select the dives to be analysed.

The last question is to what we can realistically expect Tomaz to do. I
offer to mess with the present Yearly Statistics menu item, using C/C++ to
print only the numeric statistics of one of the four variables and to
select which variable is being shown in text. Then Tomaz can take the text
and turn it into a graphic that is mobile-compatible. Someone else may wish
to adapt the filter tool. But first we need some type of consensus that the
above approach is indeed the one to go.

Apologies for a long email.
Kind regards,
willem
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