How to find the vaule of a 2-D plot at certain point

I have drawn a 2-D plot using the attached data points in matlab.

I would like to find the exact value of the function at exact x coordinates such as 1.2, 1.3 and etc.

The exact value of the function at these points are not knwon.

Which function should I use to find the values?

Answer 1

[Alan Stevens]

Use interp1 to interpolate between known values. Of course you can't guarantee exact values unless you know the exact form of the function!

[Julian M]

I used interp1 function and it gave me very resoanable estimation.