# How can I graph a vertical line using x-scaling? I have developed an interactive demonstration that moves the slope of a straight line as a function of an input parameter. The line is shown as yBopB = L2VB*x + b with internal x scaling. At some point, the slope L2VB goes to zero. A line that is supposed to be perfectly vertical disappears from the graph!

To fix this, I have resorted to the approach below. In this, at a point of zero slope, I essentially increment the x scale only by an infinitesimal amount.

if (VB == 0)
SetScale/I x xB,1.00001*xB,"", yBopB
yBopB = xB*(p + 1)
elseif (VB < 0)
L2VB = (1/VB) + 1
SetScale/P x xB,-0.01,"", yBopB
yBopB = L2VB*x - (L2VB - 1)*xB
else
L2VB = (1/VB) + 1
SetScale/P x xB,0.01,"", yBopB
yBopB = L2VB*x - (L2VB - 1)*xB
endif

I know that this problem can also be solved by plotting yBopB versus a separate xBopB wave, where xBoP = b will create a vertical line. But ... is there a cleverer way to achieve what I need ... graphing what should be a perfectly vertical line from a wave that has internal x-scaling?

@jtigor ... The approach that I've given works for a line thickness of 2.

What I am asking is whether I have missed a way to set the x-scaling of a wave as below to create a wave where all y values are at the same x (i.e. to create a vertical line from the scaled wave).

`SetScale/P x xB,0,"", yBopB`