You can use tableas an intermediate file and do the interpolation in the usual way:
set table "data2.txt"
plot "data.txt" using 1:2 notitle smooth csplines
unset table
set xrange [10:13]
plot "data2.txt" using 2:1 w l notitle

If you want a higher resolution, you can use it set samplesbefore plotting in a table.
source
share