There are ways to have gnuplot bin your data for you which revolve around
binwidth=5
bin(x,width)=width*floor(x/width)
plot 'datafile' using (bin($1,binwidth)):(1.0) smooth freq with boxes
And there are ways to plot stacked histograms from pre-binned data, using
set style data histogram
set style histogram rowstacked
plot 'test.dat' using 2:xtic(1) title 'Col1', '' using 3 title 'Col2'
Is there a way to get the best of both worlds? I can
plot 'a.dat' using (bin($1,binwidth)):(1.0) smooth freq with boxes lc 'red' ,\
'b.dat' using (bin($1,binwidth)):(1.0) smooth freq with boxes lc 'blue'
but if I set style fill solid the first plot is drawn over.
You can write the smoothed data to an external file and then plot this temporary file as histogram:
binwidth=5
bin(x,width)=width*floor(x/width)
set table 'temp.dat'
plot 'a.dat' using (bin($1,binwidth)):(1.0) smooth freq, \
'b.dat' using (bin($1,binwidth)) smooth freq
unset table
set style data histogram
set style histogram rowstacked
plot 'temp.dat' using 2:xtic(1) index 0 title 'a.dat', '' using 2 index 1 title 'b.dat'
The two smoothed plots of a.dat and b.dat are both saved in the file temp.dat, delimited by two blank lines. So, they can accessed for plotting using the index option.