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Re: delayplots with human friendly time on x-axis


Henk,

> > However, for plots-on-demand there is still a (difficult to solve)
> > problem:  upto 7 days the present code let's ROOT decided on 
> > the number of divisions (labels) for the x-axis (prefering hh:mm
> > upto periods of 3 days), but with >7 day periods the default
> > algorithm for 'mm dd' divisions don't work: you have to set
> > the number of divisions in the code.
> 
> Can't you just put hours there? e.g. "0:00, 12:00, 0:00, 12:00, ..."
> leaving it up to the user to interpret that as "7/11, 0:00 ; 7/11, 12:00 ;
> 8/11, 0:00, ..." by combining the title and x-axis?

hours:minutes are prefered for periods *up to* three days; after that you 
get too many identical labels on the x-axis; at a first glance you
do not see which day a particular part of the graph corresponds too.

For long time periods hours don't work at all: it is impossible
to label every individual day in a >7 day plot; you have two skip
one or more days (so you won't know which day a 00:00 label corresponds
to) Putting 'month/day' instead solves the problem *PROVIDED* the total
number of days is a multiple of the #days in the interval.
When you hardcode the number-of-divisions, ROOT wants to make equidistant
intervals, so you could end up with labels that are NOT at the start of a day.

see for example:
http://iii.ripe.net/cgi-bin/pod?SRC=tt01.ripe.net&date_start=20001019&time_start=&DST=tt13.ripe.net&date_end=20001030&time_end=&format=gif&SUBMIT=Submit

i.e. a plot with 11days of data, from 20001019 to 20001030
it has 6 six divisions, obviously NOT on date boundaries; 
still the axis carries labels "Oct 19, 20, 22" ....

> > Hmm, perhaps we should put make plots-on-demand less flexible, and
> > only offer a subset of specific time intervals (starting at user
> > specified day)?
> 
> If this solves your problem, then in first order yes, but in second order
> I think 1 day is too rough for zooming into problems that existed for a
> short while, probably across day-boundaries.  How about offering a choice
> of: Month, Week, Day (all starting at 0:00) and Hours (starting at N:00
> and running for a number of hours)?

Anything up to 8 days is not a problem; ROOT will automagically come
up with something sensible. With >=8 days, we are better off allowing
only specific intervals (e.g. 10, 14, 18, 24 and 30 days).

Anyway, issues like these and some 'bugs' in shorter than a day / cross 
day-boundaries plots make that the current Plot-on-demand is really
alpha code; more time is needed to make it a good service we could offer
to the TestBox hosts  (but with the lack of response to my recent mail
to tt-host list, I'm not sure if hosts are interested in this).

> > P.S. If there are no objections, the new delayplots will become
> >      production version tomorrow.
> 
> Please send a reply to ticket 22651 when you have done this.

new version is installed, I'll send the reply next.

-- Rene





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