Line plot in GnuPlot where line color is a third column in my data file?

Question

I have a datafile that looks like this:

1 1.0 0 2 1.5 0 3 0.0 1 4 1.2 2 5 1.0 1 6 1.1 1 

where the first column is my X value, the second column is my Y value, and the third column is a color. I'd like for each line segment to be colored according to the third column. So the first two line segments would be "color 1", the next would be "color 2", the next would be "color 3", and the final two would be "color 1" again.

I tried:

plot 'file.dat' using 1:2:3 with lines rgb variable; 

But my line was all black.

Is this possible in gnuplot?

Thanks, Gabe

Answer 1

This following works for me (gnuplot 4.4)

plot "./file.dat" u 1:2:3 with lines  palette 

Hope this helps.

When I ran your code gnuplot couldn't pass the "rgb" part.

For an example of using the variable tag see the similar question: GNUPLOT: dot plot with data depending dot size

with the useful examples found here: http://gnuplot.sourceforge.net/demo/pointsize.html

All the best

Tom

Answer 2

plot 'foo.dat' with lines linecolor variable 

or abbreviated:

plot 'foo.dat' w l lc var