How to measure graph wave distance ?

I want to find the distance between the graph and straight line as shown below,

Thank you.

[Shashi Kiran]

Hi @MARLIANA HAFIZA,

Do you have the specific points on the curve and the line available?

[MARLIANA HAFIZA]

I want to find the distance for all the points together. I have the points value for each line

Answer 1

[Bruno Luong]

It looks like you need to rotate the whole picture (red line + blue curve) to minus the slope of the red line.

After rotation the redline become horizontal; then tthe distance is just the differential y-coordinate (after rotation) of the any blue points to the y-coordinate of the horizontal red line

Rotation is multiply x-y coordinates by matrix, see wiki

R := [cos(theta) -sin(theta);

sin(theta) cos(theta)]

R*[x;y]

Use theta as minus the slope of red line. You must know the redlinne equaltion, so its slope somehow.