Combining acspline with filledcurve on data

Question

I know how to use filledcurve with using 1:2:3 to fill the area between the curves described by columns 2 and 3.

I also know how to smooth a single curve using acsplines with using 1:2:(0.1) (with 0.1 being the smoothing weight for each point).

But I fail to combine the two, i.e. fill the area between two smoothed curves. All variants I try give me error messages like duplicated or contradicting arguments in datafile options.

This is what I tried:

plot 'datafile' using 1:2:3:(0.1):(0.1) smooth acs with lines
plot 'datafile' using 1:2:(0.1):3:(0.1) smooth acs with lines

Is this combination possible at all? How is the syntax then?

Answer 1

I guess you can't combine smooth acspline and with filledcurves, but I also don't know why this shouldn't be possible. Well, as a workaround, plot your smooth acspline curve into a data table first and then plot it with filledcurves.

Code:

### filled acspline curve
reset session

$Data <<EOD
1 2
2 4
3 3
4 1
EOD

# plot your acspline data into a table
set table $ACSpline
    plot $Data u 1:2 smooth acspline
unset table

set style fill transparent solid 0.1 

plot $Data u 1:2 w lp pt 7 lc rgb "black" ti "Original data", \
     $Data u 1:2 smooth acspline lw 2 lc rgb "red" ti "acspline", \
     $ACSpline u 1:2 w filledcurves x1 lc rgb "red" ti "acspline filled"
### end of code

Result:

Addition:

There is another way to get data into a table. Check help set print. With this, you can get the data of the two splines into one datablock and can plot the area between them. Maybe someone knows a simpler way to achieve this.

Code:

### filled curve between two acsplines
reset session

$Data <<EOD
1 2 4
2 4 1
3 3 0
4 1 3
EOD

# plot your acspline data into tables
set table $ACSpline1
    plot $Data u 1:2:(1) smooth acspline
unset table
set table $ACSpline2
    plot $Data u 1:3:(1) smooth acspline
unset table
set print $BetweenSplines
    do for [i=1:|$ACSpline1|] {
        print sprintf("%s %s %s",word($ACSpline1[i],1),word($ACSpline1[i],2),word($ACSpline2[i],2))
    }
set print

set style fill transparent solid 0.5 

plot $Data u 1:2 w lp pt 7 lc rgb "black" ti "Original data col 2", \
     $Data u 1:3 w lp pt 7 lc rgb "blue" ti "Original data col 3", \
     $ACSpline1 u 1:2 w l lw 2 lc rgb "red" ti "acspline col 2", \
     $ACSpline2 u 1:2 w l lw 2 lc rgb "green" ti "acspline col 3", \
     $BetweenSplines u 1:2:3 w filledcurves lc rgb "yellow" ti "acspline filled"
### end of code

Result: