plotting percentage of a max value

Hello,

I have 15 different graphs. For each one I have found the max value. I want to plot a dot on the curve at 5% of the max value. Could someone help please?

[Ameer Hamza]

What do you mean by "5% of the max value". The circle in your image is right at peak.

[Aero32]

I would like to plot 5% of the peak value

Answer 1

[KSSV]

You may get multiple values for this case.

[val,idx] = max(y) ; 
y1 = val*5/100 ; 
% Increase the reoslution of (x,y) data 
xi = linspace(min(x),max(x),1000) ;  % change the number of needed 
yi = interp1(x,y,xi) ; 
% Get the index of y1 
idx = abs(yi-y1)<=10^-3 ;  % change the tolerance if needed 
iwant = [xi(idx) yi(idx)] ;