> > I would consider this breaking the plot, in that gnuplot no longer lines > up the two columns of data. > My fault, gnuplot does indeed still line up the data as appropriate when missing values are simply replaced with blank space rather than "". I've just pushed up changes to gnuplot code blocks which add a :missing header argument which may be used to specify a missing value, and which replace missing values with blank space (rather than "") when the missing header argument is not supplied. The attached org-mode file demonstrates both. Press C-c C-v v on each code block, and then open up the data file to see the effects of the header argument.