[tor-dev] Feedback on recent Globe improvements

[thomas lörtsch]

On 03 Apr 2014, at 10:10, Karsten Loesing <karsten at torproject.org> wrote:

> On 02/04/14 15:58, thomas lörtsch wrote:
>> 
>> On 02 Apr 2014, at 15:40, Karsten Loesing <karsten at torproject.org> wrote:

>> 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.

Adding more graphs definitely breaks the idea of gathering all graphs in one graphic at the same time. Still there probably are usecases where comparision of different graphs is helpful. Another way to tackle the problem could be to have one more graphing area in which graphs are selectable from a menu - again color coded if it’s more than one and the scales color coded as well. That might be an addition to the existing graphing areas, by default populated with a preselected assortment of graphs that often need to be examined in combination. 


>>> 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.

Generally that’s probably right but the advantages would have been considerable. If this was the only problem I would have dimissed it.

> 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.

Ah, very good. Thanks!


Bye
Thomas