I'd like to do pm3d splots of datafiles using three columns for x, y, z and a fourth column for the color at that point. Can gnuplot do that without first pre-processing the data into datablocks? If not, what should the files look like to specify a colour independent of the third column? -JimC -- James Cloos <cloos at jhcloos.com> OpenPGP: 1024D/ED7DAEA6