Plot range for line of fit using date on the x-axis in gnuplot -

i trying plot fit function (col 3 versus col 7) dataset given below

 28-08-1991 20-12-1992  24-04-1992  -263347200  -221875200  -242611200  0.060859   20-12-1992 02-09-1993  27-04-1993  -221875200  -199756800  -210816000  0.064681   10-09-1996 13-09-1997  13-03-1997  -104371200  -72576000   -88473600   0.095728 ...... 

i script plot fit range of dates, between 1995 2003. unable range function right since gnuplot handle dates past year 2000.

please find code below.

 set xdata time  set timefmt "%d-%m-%y"  set xrange ["01-01-1991":"01-01-2015"]   set yrange [0.0:0.4]  offset = 24*60*60   f(x) = 1.e-7*m*(x-offset)+c   fit f(x) "file"  using 3:7  via m,c  set fit logfile 'file.log'   plot '(x < "24-02-1993" ) ? f(x) : 1/0' title "best fit" lines ls 5 

the variable x in plot contain time in form of seconds since 1/1/1970. in order compare date, need convert date same format strptime.

if additionally remove ' around function plot in mwe, get:

plot (x<strptime("%d-%m-%y","24-02-1993"))?f(x):1/0 title "best fit" lines ls 5 

note you've fitted f(x) on whole dataset, not on dates before 24-02-1993, it's plot restricted these dates.