gnuplot-info

[Gnuplot-info] X axis time scaling

[LarsEr <in...@lb...>]

I want to create a plot that have an x range over the last 24 hours with the
current time as last position, is that possible? E.g start at 9.00 and stop
at 8.59. 

Thanks

Lars



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Re: [Gnuplot-info] X axis time scaling

[Theo <th...@gm...>]

Hi Lars,

does the following work for you?

set xdata time
set format x "%H:%M"
set xrange [ time(0) - 86400 : time(0) ]    # 86400 sec = 1 day
set label 1 strftime("%T",time(0)) at screen 0.5,0.5   # show the 
current time

Theo.

Re: [Gnuplot-info] X axis time scaling

[LarsEr <in...@lb...>]

Thanks a lot Theo! That solved my problem. 
Still have a minor issue, it's a ruby script and gnuplot seems to handle a
Time different, don't know if it's day light saving or time zon (1 hour
differ).
/ Lars.



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Re: [Gnuplot-info] X axis time scaling

[Theo <th...@gm...>]

Yes, I also noticed that the time is not the time which I see as my 
actual local time.

That's what the gnuplot 4.6 manual says:

Internally all times and dates are converted to the number of seconds 
from the year 2000.
...
The conversion to and from seconds assumes Universal Time (which is the 
same as Greenwich Standard Time). There is no provision for changing the 
time zone or for daylight savings. If all your data refer to the same 
time zone (and are all either daylight or standard) you don't need to 
worry about these things. But if the absolute time is crucial for your 
application, you'll need to convert to UT yourself.