Plot specified points first then data from file using gnuplot

Question

I am trying to plot data from two sources: (1) specific points that define a diagonal from (0, 0) to (1, 1), and (2) file containing my analyzed data. Currently, I can do this using the following command:

plot [0:1][0:1] 'sample.dat' using 1:2 with lines,\
'-' title 'random AUC=0.50' with lines dashtype 2
0 0
0 0
0.5 0.5
1 1
e

which outputs the following:

However, I want the diagonal line to appear first. How can I achieve this?

Answer 1

If you want to plot the diagonal, simply plot the function x.

Code:

### plot order
reset session

set size square
set xrange[0:1]
set yrange[0:1]

# create some test data
set table $Data
    plot '+' u 1:(int($1*10+1.5)/10.) w table
unset table

set key top left

plot x with lines dt 2 title 'random AUC=0.50', \
    $Data u 1:2 w l ti 'sample AUC=0.596'
### end of code

Addition:

If you want to plot arbitrary points instead of x:

$myPoints <<EOD
0    0
0.1  0.2
0.5  0.7
1.0  1.0
EOD

plot $myPoints u 1:2 w lines

Result: