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<th valign="BASELINE" nowrap="nowrap" align="RIGHT">Subject:
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<td>Re: RFC: Statistics in Subsurface</td>
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<th valign="BASELINE" nowrap="nowrap" align="RIGHT">Date: </th>
<td>Tue, 12 May 2020 21:41:08 +0200</td>
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<th valign="BASELINE" nowrap="nowrap" align="RIGHT">From: </th>
<td>Willem Ferguson <a class="moz-txt-link-rfc2396E" href="mailto:willemferguson@zoology.up.ac.za"><willemferguson@zoology.up.ac.za></a></td>
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<td><a class="moz-txt-link-abbreviated" href="mailto:willemferguson@zoology.up.ac.za">willemferguson@zoology.up.ac.za</a></td>
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<td>University of Pretoria</td>
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<th valign="BASELINE" nowrap="nowrap" align="RIGHT">To: </th>
<td>Dirk Hohndel <a class="moz-txt-link-rfc2396E" href="mailto:dirk@hohndel.org"><dirk@hohndel.org></a></td>
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<div class="moz-cite-prefix">On 2020/05/12 20:49, Dirk Hohndel
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:7A48C538-14FA-4347-BCD6-4E79807ECF06@hohndel.org">
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Hi Willem,
<div class=""><br class="">
</div>
<div class="">Thanks for responding... I wish more people got
involved into these conversations. But usually topics like
this get two or three of the 300+ people here to respond. And
then ten more will complain after we have done the next
release and they notice for the first time that we added a
feature...<br class="">
<div><br class="">
<blockquote type="cite" class="">
<div class="">On May 12, 2020, at 12:59 AM, Willem
Ferguson <<a
href="mailto:willemferguson@zoology.up.ac.za" class=""
moz-do-not-send="true">willemferguson@zoology.up.ac.za</a>>
wrote:</div>
<div class="">
<div class="">
<p class="">I understand Berthold's request with
respect to temporal sequences. When developing such
a temporal facility there is an important caveat.
Emphatically, such temporal representations do not
provide any clear *explanation* of anything: it is
just a temporal pattern. For instance a decrease in
SAC rate over time does not necessarily imply any
improvement in physiological ability but may reflect
adoption of new equipment or change in dive sites.
Any explanation of a temporal trend is dependent on
the understanding of the USER, not on the SOFTWARE.
So, when dealing with temporal trends, one needs to
consider carefully the intended type of use of it. I
think Berthold is more concerned with continuous
variables such as temperature, SAC, dive duration,
depth, etc which could probably be reasonably easily
implemented. To represent categorical variables such
as tags, dive mode, people and suit (one could even
add dive site) is a totally different issue
requiring a totally different type of visual
representation. </p>
</div>
</div>
</blockquote>
<div><br class="">
</div>
<div>I was in complete agreement until the very last
sentence. I don't understand why this 'per se' requires a
"totally different type of visual representation".</div>
<div>Let's say I am charting SAC over my criteria. Let's
assume I'm using box and whiskers charts to easily show
the quartiles. The values on x-axis have implications for
the interpretation, of course, but whether the x-axis is
months of the year, the suit worn, the maximum depth of
the dive, the tags present on the dive (e.g., teaching
dive or non-teaching dive) has absolutely no impact on how
this should be visually represented...</div>
<br class="">
<blockquote type="cite" class="">
<div class="">
<div class="">
<p class="">It would help, in this discussion, if one
were to distinguish between the filtering aspect and
the statistics display aspect and state that with
respect to the argument. In Dirk's artwork above, I
am not sure how the constraints will be used. Are we
talking of the filtering process or the stats
display mechanism? Let's say "Suit" is a constraint
and two dates are provided. I am not sure what the
expected result of the operation would be. Ahh, the
problems of communication.<br class="">
</p>
</div>
</div>
</blockquote>
<div><br class="">
</div>
<div>What I was trying to describe was a way to create
criteria that can be used for columns in the
visualization. You go through this filter process, name
the result, and that name becomes one of the available
labels over which you can chart the values.</div>
<div>Again, as I said before, I may simply be
over-engineering this.</div>
<br class="">
<blockquote type="cite" class="">
<div class="">
<div class="">
<p class=""> </p>
<p class="">In general, in my opinion, the existing
filter layout is a good starting point (I would add
the variables of dive depth and dive duration
because they are the two variables that
fundamentally define a dive). As a filtering
mechanism the current implementation is
ultra-flexible.</p>
</div>
</div>
</blockquote>
<div><br class="">
</div>
While I respect your opinion, let me politely state that
personally I believe that the current filter widget is a
disaster and extremely unintuitive to use. That's not a
criticism of the original author, nor of the people who have
added to it - but yeah, that thing is a mess.</div>
<div><br class="">
<blockquote type="cite" class="">
<div class="">
<div class="">
<p class="">As far as UI for filter sets are concerned
the minimum component count would include: Combobox
of existing named filters within the set. Button:
add current filter to filter set. These could
potentially reside at the top right of the current
filter panel. But there might be a need to give
filter set a name as well. That would need a text
box.<br class="">
</p>
</div>
</div>
</blockquote>
<div><br class="">
</div>
Making the current widget more convoluted and more confusing
was not a direction that I was envisioning us to go.</div>
<div><br class="">
</div>
<div><br class="">
</div>
<div>Maybe we need to rain in the crazy German and go back to
something much more basic. Something like ten predefined
sets of criteria. And only apply them to the filtered dive
list.</div>
<div><br class="">
</div>
<div>So.</div>
<div>(1) per month</div>
<div>(2) per year</div>
<div>(3) per trip</div>
<div>(4) by max depth in 10m increments</div>
<div>(5) by duration in 10min increments</div>
<div>(6) by min temperature in 10F / 5C increments</div>
<div>(7) by type (for people who track more than SCUBA)</div>
<div>(8) by suit (that's likely a fairly small set for most
people)</div>
<div>(9) by tags (that one I'm unclear about - would likely
need some more ability to influence how this is drawn - but
straight forward would be to draw them in pairs of two, left
one represents with the tag, right one without the tag)</div>
<div>(10) by people? (no idea how / why)</div>
<div>
<div>(11) by full text? (no idea how / why)</div>
<div class=""><br class="">
</div>
<div class="">If we drop the last three this seems fairly
obvious how to do.</div>
<div class=""><br class="">
</div>
<div class="">Next comes the question of visualization. That
might depend on the data (so the columns of the yearly
statistics). At first glance I thought that box and
whiskers charts might be useful, or more simplified min /
avg / max charts (so floating bar with a circle for the
average)</div>
<div class=""><br class="">
</div>
<div class=""><br class="">
</div>
<div class=""><img src="https://i.stack.imgur.com/oVDLR.png"
alt="the 'candlesticks' plot" class=""
moz-do-not-send="true"><img
src="https://lh3.googleusercontent.com/proxy/p-DbBBZEQJR6LpDHzpm5lqxpBTmg1KJtrlb9_lnClsXY0tj4a1Lsi5iMyywTfgItp_QFjEW4FPnPWA3jrEa56ftjXB8Ap2N9FHt_zM7S7bbe7it0FfRLbXE9p1sJSUhfIwU1"
alt="Make an Avg-Max-Min Chart in Microsoft Excel"
class="" moz-do-not-send="true"></div>
<div class=""><br class="">
</div>
<div class="">Are there any columns that couldn't be
visualized with that?</div>
<div class=""><br class="">
</div>
<div class="">/D</div>
<div class=""><br class="">
</div>
<div class=""><br class="">
</div>
</div>
</div>
</blockquote>
<p>I am comfortable with your points of view, above. The 10m or
10min increments could easily be configurable. For instance a
person with OW certification (dives to 18m only with almost all
dives in the 10-18m range) would probably want at most a 5m
increment in depth. Unless I understand you wrongly (again).
Normally with statistical software (like R) the default
increment is determined by the (max-min) range of the data as
well as the number of data points being plotted. Of course I
would not like an increment of 3.674 m of depth as might be the
case when increment is automatically calculated by machine. My
only point is that a single fixed increment is possibly
restrictive and it would help if there were a simple rule to do
some adjustment of the increment.<br>
</p>
<p>As far as specifying categories like tags I like the present UI
where one could specify a number of tags to be included in the
filter, giving great flexibility. Again my impression of such a
plot possibly differs from yours. I like your binary set idea (a
set including compared to a set excluding). But I would more
realistically often want to compare (e.g. SAC when comparing two
tags "air" and "nitrox"), a use case which does not necessarily
imply a binary comparison because it could compare 3 or 4 tags.
Does this make sense at all?</p>
<p>Lastly, I do not like candlestick graphs because the
application in econometrics does not include the equivalent of a
mean value. It is meant to indicate the limits and sometimes
direction of change within a specific time period giving rise to
the candle forming the central part of the graph. In my opinion
a minimal box and whisker approach is more readily
interpretable.</p>
<p>I am very excited that this discussion is actually happening
that that a window of opportunity exists with people like Tomaz
and Berthold interested in being involved. <br>
</p>
<p>Kind regards,</p>
<p>willem</p>
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