Extract data from plot

Hello all I have a plotted a graph with x=1 2 3 4 5 and y = 2 4 6 8 10. Now I want to mark y= 6.5 on the plot. How to do it. I have asked this question in a simple way but the actual data I have is so big. Hoping for suggestions Thanking you

Answer 1

[esat gulhan]

Maybe like this

clc;clear;
x=[1 2 3 4 5]; %x data
y =[2 4 6 8 10];%y data
yy=6.5 % y value you intend to reach
xx = interp1(y,x,yy,'spline') %interpolation type, i choose spline, but you can choose pchip,lineer etc...
plot(xx,yy,'o'); %plot value
hold on
plot(x,y,'r'); grid on; %plot x y datas

[Vinay Srinivasan]

First of all thank you so much for replying In the line XY=interp1(y,x,XY,'spline') What is the y and X value I should give ?

[esat gulhan]

it depends what you want. yy is changeble. If you change yy=6.5 ,yy=6 it changes x =3, if you give yy =3 x will be 1.5.

If you write yy=[3 5 7] you see 1.5 2.5 3.5 three marks on graph.

[Vinay Srinivasan]

Ok thank you so much, it worked