What causes the jagged effect in gnu plot filler and how can it be improved?

[CAF123]

I've produced a plot showing a best fit value and one with error estimate included (the dashed yellow line). I want to shade the region between the best fit value and this yellow line. As can be seen, the gnu plot filler I use is not optimal and leaves a residual jaggy effect and the shaded region does not extend all the way to the yellow curve. What might causes this and is there a way, within gnu plot, to allow for an improved filling?

I use the following gnu plot code to generate shaded region

 plot 'data.dat' u 1:($18+$19):($18-$19) w filledcurve ls 999 fs solid 0.12 bo notitle,\

 

[Future Bruno]

'data.dat' u 1:18 w l ls 999 lw 2 pi 0.5 lc rgb 'black' notitleThe jagged effect is likely caused by the fact that the filledcurve command uses linear interpolation between data points, while your yellow line is not a linear function of x. To improve the filling you can use different smoothing techniques. For example, you could use a spline fit to smooth the data before using the filledcurve command. Alternatively, you could use the gnuplot pm3d command instead of the filledcurve command.