[tor-dev] Feedback on recent Globe improvements

[Karsten Loesing]

On 02/04/14 15:58, thomas lörtsch wrote:
> 
> On 02 Apr 2014, at 15:40, Karsten Loesing <karsten at torproject.org> wrote:
> 
>> On 02/04/14 11:46, thomas lörtsch wrote:
>>> nice work! One nitpick: if the legend to the left was colour coded
>>> like the graphs I would not need to hover over the graphs to see
>>> which curve reflects which category.
>>
>> Right, I asked the same thing on the ticket:
>>
>> https://trac.torproject.org/projects/tor/ticket/11349
> 
> Ah, cool. I didn’t know the URL for the tracker.

Yeah, it's a bit confusing with the code being hosted on GitHub, the
preview versions running on Christian's own server, the stable version
running on a Tor VM, and issues being tracked in Tor's Trac.  The only
solution is that somebody meets Christian in person, makes sure he's a
human, and signs his PGP key, so that we can give him access to do
everything on Tor gear. :)

>>> I was thinking about how it could be possible to combine all
>>> perspectives in one graphing window. Especially the seperate window
>>> for the bandwidth perspective seems a little wasted and disconnected.
>>> Maybe the bandwidth could be rendered as a backdrop plane behind the
>>> curves, then on top / in front of it the bandwidth graphs in shades
>>> of e.g. red to yellow and the weights graphs in shades of blue to
>>> green. Not sure if that works or if you have tried it already. Would
>>> need 3 scales on the left, probably colour coded again. Benefit would
>>> be that the time slider on the bottom would work for all perspectives
>>> synchronously. I always like to have all the information in one place
>>> so that my eye doesnt have to wonder, my brain doesn’t have to
>>> correlate etc. But of course there’s a treshold where the interface
>>> get’s too cluttered to be useful anymore.
>>
>> Hmm.  I don't fully understand the graph that you suggest.  Can you
>> attach a draft, maybe even something drawn on paper?
> 
> Just imagine all curves in one graphic instead of three. And then I’m making suggestions on how to make that mess readable again :)

Indeed.  And imagine how the graph becomes even less readable when we
add two more graphs for absolute numbers for advertised bandwidth and
consensus weight...  I'm not sure how putting everything into one graph
is going to scale.  Though I see the motivation for having everything in
one place.

>> My initial reaction is that this is going to be a heavily overloaded
>> graph.  
> 
> That is of course the problem. It would have to be tested how far color coding can help. Probably your instinct is right and it’s not feasable. Maybe Christian already tried and dismissed it.
> 
>> In particular putting three different scales on the y axis is
>> discouraged, I think.
> 
> That’s solvable. Bandwidth scale to the left, weights to the right, and uptime doesn’t really need a scale (just a legend saying that 100% equals the full height of the graphic).

I was not referring to technical limitations, but I think putting more
than one scale on an axis is discouraged in general.  I would have to
read up the arguments against it, but I remember Hadley Wickham, the
ggplot2 author, bringing up some reasons why it's a Bad Idea.

In fact, here's a quick web search, though this is probably not the best
hit:

https://stat.ethz.ch/pipermail/r-help/2006-August/111047.html

>> Also, with all the different colors this graph
>> becomes pretty hard to understand for color-blind people.
> 
> It’s definitely not for color-blind people, but I don’t see a way around that since different styles for strokes (like ‘dotted’ etc) make the curves pretty hard. I don’t know about the details though - which colors are more problematic then others, what are critical tresholds between shades of colors etc.

I agree that the alternative to using many colors is *not* to use
different stroke styles.

The better alternative is probably to make separate graphs with fewer
colors or no colors at all.  I really liked the GitHub graphs, mentioned
earlier in this thread, being all black and white.  But I don't see how
we can remove color as dimension entirely.

As for problematic colors for color-blind people, there's a related
ticket about metrics website graphs:

https://trac.torproject.org/projects/tor/ticket/6463

There are a couple of useful links in there.

>> If there's a way to overcome these problems, happy to brainstorm more
>> about the topic. :)
> 
> Ciao

Cheers!
Karsten