[gnuplot] how to drwo a single point

There are so many different ways to drow a point.

http://www.gnuplotting.org/plotting-single-points/

http://stackoverflow.com/questions/19452516/add-a-single-point-at-an-existing-plot

(1) Use label

I think the most simple way is usage of empty label.

set label at xPos, yPos, zPos "" point pointtype 7 pointsize 2







(2) Use standard input "-"

plot '-' w p, '-' w p, '-' w p
1 2
e
1 3
e
2 4
e

(3) Use special filename "+": 

see an another example (it is convenient for discrete sampling)

(4) Use object

set object circle at first -5,5 radius char 0.5 \
    fillstyle empty border lc rgb '#aa1100' lw 2
set object circle at graph 0.5,0.9 radius char 1 arc [0:-90] \
    fillcolor rgb 'red' fillstyle solid noborder
set object rectangle at screen 0.6, 0.2 size char 1, char 0.6 \
    fillcolor rgb 'blue' fillstyle solid border lt 2 lw 2

plot x