calculating unknown points by pchip

I have extracted points on the curve from 900nm to 1100nm using "GRAB IT". But I have got exact values up to 1020nm. How to find absorption coefficient at 1064nm. Experts said to use pchip. How can i get it?

[Image Analyst]

I don't know what GRAB IT is. You forgot to attach your x and y data. We can't do anything yet. In the meantime, attached is an example where I used it to smooth a boundary of a blob. http://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer

[Sathyamoorthy R]

x = -5:5;
y = [1 1 1 1 0 0 1 2 2 2 2];
p = pchip(x,y);

If I run the above code, I am getting an error at the third line. Could you help me to resolve it?

[Image Analyst]

You forgot to post the error!!!

It works for me:

x = -5:5
y = [1 1 1 1 0 0 1 2 2 2 2]
p = pchip(x,y)

x =
    -5    -4    -3    -2    -1     0     1     2     3     4     5
y =
     1     1     1     1     0     0     1     2     2     2     2
p = 
  struct with fields:

        form: 'pp'
      breaks: [-5 -4 -3 -2 -1 0 1 2 3 4 5]
       coefs: [10×4 double]
      pieces: 10
       order: 4
         dim: 1

http://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer

http://www.mathworks.com/matlabcentral/answers/13205#answer_18099 though I fixed this formatting for you.