Question

I’ve a source data like this:

       35    40
-15    15.0  15.1
-10    17.2  17.4
-5     19.7  19.8

and I need to find the value in (-16, 37). I’ve tried with linear interpolation but I can solve only with (x,y) couple of values. Could you help me?

thanks a lot,
Andrea

Answer 1

thanks to all, your suggests has been very helpful for me to understand better the problem.

In the beginning I’ve putted the problem in a wrong way because I’ve take cue from the graphical representation of the data, a matrix. But, after some “mumble” 🙂 I’ve understand that the correct way to represent the problem was:

f(x1,x2) = y

       35    40
-15    15.0  15.1
-10    17.2  17.4
-5     19.7  19.8

so, i.e. f(35, -15) = 15.0

To obtain value in x1 = 37 and x2 = -13 I can use bilinear interpolation.
The graphical representation of the problem in

http://en.wikipedia.org/wiki/File:Bilinear_interpolation.png

was my flash of inspiration.

Thanks to all!

Andrea