Splot (contour, view map) and plot on same graph

2
votes

I am trying to plot two overlaying graphs.

The first is a simple x-y points plot:

plot myfile u 1:2

The second is a contour plot at level 0, which I can plot with the following commands:

set contour
unset surface
set view map
set cntrparam levels discrete 0
splot a0 + a1*x + a2*y + a3*x**2 + a4*x*y + a5*y**2 + a6*x**3 + a7*x**2*y + a8*x*y**2 + a9*y**3

a0-a9 are constants

Both use the same xrange and yrange.

How can I plot them both in the same graph?

1
gnuplot

1 Answers

3
votes

This is a somewhat tricky one. You can write the contours to a file using

untested

set table 'datafile'
set contour
#contour options
splot ... with contours
unset table

Then you can plot that data with lines:

set term ...
set output ...
set view map
splot myfile u 1:2:(0.0), 'datafile'  u 1:2:3 w lines