How to output smooth cspline curve as a data file

Question

Does anybody know how to extract some data of smooth cspline curve for a given data?

For instance, there is a data file which has 2 columns corresponding to x and y

Answer 1

Use set table 'temp.dat' to redirect the plotted data points to an external file

set table 'temp.dat'
plot 'myfile.dat' using 1:2 smooth cspline
unset table

To test it

plot 'myfile.dat' using 1:2 with points title 'original points',\
     'temp.dat' using 1:2 with lines title 'smoothed curve'