Re: [Gnuplot-info] Gnuplot X-Range as midnight last night to midnight tonight

[hchiPer <hc...@gm...>]

I've copied pasted your example and it is not working (error message = 
line 39: all points y value undefined!)

I could make it work with the following modifications:

- remove the 3 tabs and leave just 1 in the data file

- change the time format:

     set timefmt "%H:%M:%S" ### instead of set timefmt "%Y-%m-%d\t%H:%M:%S"

- remove the 2 system calls

- change the xrange:

     set xrange ["00:00:00":"23:59:59"]

- use column 2 instead of column 1 in the plot command:

     plot "./x.txt" using 2:3:(rgb3($3)) with line lw 1 lc rgb variable 
notitle


Le 14/04/24 à 11:13, Lars Noodén via gnuplot-info a écrit :
>
> Greetings,
>
> Thanks  for Gnuplot.  I've been using it to graph various sensor
> readings for some years now.  From time to time, it becomes useful to
> make modifications and between the documentation, various examples, and
> trial-and-error the results look nice in addition to being functional.
>
> My question is how would I set X-Range to be the time from 00:00:00 to
> 23:59:59 on the current date?  Specifically, I would like the X-axis to
> range from midnight to midnight for the current date.
>
> I can't hard code it in to Gnuplot since, obviously, the date changes
> every day.  Also since the data to be graphed comes in at different
> times during the day, using it provides an inconsistent X-Range which
> changes as the hours go by.  So that can't be used either.
>
> One way seems to be to use system() to call the date(1) utility twice
> and storing output in variables.  This is seen in lines 25 through 27 of
> the script below.
>
> Perhaps there is a better way without needing to use the system() call?
>
> /Lars
>
> PS.  The file x.txt has three tab-delimited columns. e.g.
>
> 2024-04-14      10:40:00        20.375
> 2024-04-14      10:50:00        20.375
> 2024-04-14      11:00:00        20.437
> 2024-04-14      11:10:00        20.5
> 2024-04-14      11:20:00        20.5
>
>
> -- 
>
> #!/usr/bin/gnuplot
>
> set output "./x.png"
> set term png size 400, 400
> set term png background "#fff0f0f0"
> set termoption font "Liberation Sans, 12"
>
> set datafile separator tab
>
> set xdata time
> set timefmt "%Y-%m-%d\t%H:%M:%S"
> set xtics format "%H" font "Liberation Sans, 11"
> set xtics timedate
>
> # draw line at zero
> set arrow 1 from graph 0, first 0.0 to graph 1, \
>         first 0.0 nohead lw 2 lc rgb "#e0e0e0" back
>
> set ytics format "%0.0f°" font "Liberation Sans, 11"
> set yrange [*<-5:30<*] writeback
> # set yrange restore
>
> xs=system("date -d '00:00:00' +'%F\t%T'")
> xe=system("date -d '23:59:59' +'%F\t%T'")
> set xrange [xs:xe]
>
> set xlabel "Time" font "Liberation Sans, 14"
> set ylabel "Degrees Celsius" font "Liberation Sans, 14"
>
> set title "Since Midnight" font "Liberation Sans, 16"
>
> # probe 1, change color when at or below 15°C
> rgb3(b) = (b <= 15 ? 32767 : 65280 )
>
> plot \
>         "./x.txt" \
>         using 1:3:(rgb3($3)) \
>                 with line lw 1 lc rgb variable \
>                 title ""
>
>
>
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