An answer to this requires first a proper explanation of different possibilities to organize the data:
Two empty rows separate two different data sets. These aren't connected at all, no lines are drawn between them. In your case this is required, because
gnuplot
doesn't support the kind of grid you have for a single surface.pm3d
works only within a single data set, and needs a regular grid (see the pm3d demos). Two lines (isolines) of a single surface must be separated by only one empty row.
Still you have an irregular grid, which pm3d
can't handle. Inside gnuplot
you can use dgrid3d
to resample your input data to get a regular grid and plot that one with pm3d
.
But dgrid3d
affects all data files of a one splot
command. So you'll also need multiplot
to use two splot
commands.
The following script shows how it could work, but as I don't have the full data set and don't know how dgrid3d
copes with that many data sets (see 1. above), this is only a very rough guide:
set multiplot
set pm3d at b
set dgrid3d 200,200
unset key
splot 'sol.dat' nosurface
unset dgrid3d
unset pm3d
splot 'sol.dat' with lines palette
unset multiplot
That should work, but you probably need to tune the dgrid3d
call. Also, some other enhancements may be required (plotting the border, tics and colorbox only once etc.)