Gnuplot: how to plot the maximum and / or minimum value

You can do this "semi-automatically" with the command stats

. This command can extract some statistical values ​​from a dataset, but requires some tweaking:

• Extract the minimum and maximum y values, assuming your data file has two columns, the x value in the first, y values ​​in the second column

  stats 'file.dat' using 2 nooutput name 'Y_'
  
        
  
          
          
          
        
  
      

  This gives the minimum / maximum y-values ​​in the variables Y_min
  
  and Y_max
  
  , but not the corresponding x-value.

• In the previous step, you only get the corresponding indices, for which you need to run again stats
  
  to get the x values:

   stats 'file.dat' using 1 every ::Y_index_min::Y_index_min nooutput
   X_min = STATS_min
   stats 'file.dat' using 1 every ::Y_index_max::Y_index_max nooutput
   X_max = STATS_max
  
        
  
          
          
          
        
  
      

• Set labels and / or points at the appropriate coordinates

  set label 1 sprintf("%.2f", Y_min) center at first X_min,Y_min point pt 7 ps 1 offset 0,-1.5
  set label 2 sprintf("%.2f", Y_max) center at first X_max,Y_max point pt 7 ps 1 offset 0,1.5
  ...
  plot ...