MATLAB: Unstructured grid to structured grid

Question

Dear all, what would be the best way, in your opinion, to get a structured grid out of an unstructured grid?

What I have is something like this:

x  y   f
1  12  7
3  10  4
1  11  2
2.4  15  0

So basically x and y are totally random and in no specific order. What I need is to resample the values of f on a structured grid with a constant step.

I had a quick look at interp2 and it looks like it will only work if my vectors are strictly monotonic which is not the case as I have plenty of repeated values for x and y.

Thanks a lot

Answer 1

scatteredInterpolant may do what you need. Like this:

x = [1 3 1 2.4].';
y = [12 10 11 15].';
f = [7 4 2 0].';
si = scatteredInterpolant(x, y, f);   % using default linear interpolation
xint = (0.5:0.5:3.5).';      % regular grid
yint = (9.5:0.5:15.5).';
fint = si({xint yint})