Hi,
the first thing that comes to my mind is that recent gnuplot versions don't support the terminal "gif" anymore. Maybe you want to try changing that to e.g. png.

Update: Further Examination(tm) shows:

  1. No terminal "gif" in my gnuplot: 
    $ ./datesort.pl
1e-05 1e-10

gnuplot> set terminal gif
                      ^
         "27968-gps.plt", line 1: unknown or ambiguous terminal type; 
+type just 'set terminal' for a list

    [download]
  2. The resulting PNG image is a very good looking chart without any data plotted *grin*
  3. The datafile gpsmk4.dat is empty (that becomes visible easier, when you don't put your files into /tmp; not speaking of not deleting them at the end of your programm...) 
  4. if (compare_dates([$month,$day,$hour,$min,$sec], $sdate_cursor) > 0)

    [download]
    this statement is never true (your start-month is March and all data is from January...?)
    So maybe you want to check that logic...

Regards Stefan K

In reply to Re: Date sorting by stefan k
in thread Date sorting by maderman

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