You can use different coordinate systems for x and y values. The available coordinate systems are:
first
: value on the left and bottom axes.second
: value on the right and top axes.graph
: relative to the area within the axes,0,0
is bottom left and1,1
is top right.screen
: relative to the entire canvas.character
: depends on the chosen font size.
So, if your x-value should be relative to the graph, use graph 0.5
, for the y-value you can use first yval
:
set label at graph 0.5, first yval+ofs
Here, yval
is the y-value of the horizontal line, and ofs
is an offset in order to displace the label a bit.