Issue in specifying input arguments for interp2 function

I have some data in specific locations of a matrix, which I need to interpolate. The picture below (which I borrowed here) sketches the problem (only look at the blue P elements with no interest on the groupings).

I am trying to do this by using the interp2 function for 2-D interpolation. However I can't figure out how to specify the input arguments interp2(X, Y, Z, XI, YI). In particular, how should I specify the matrix Z? It should be made of the blue elements only, which are not really uniformly spaced on the grid.

Thanks for any help

Answer 1

[sixwwwwww]

you can do it as follow:

[x, y] = meshgrid(1:20); % Define x-y grid on which z values will be located
z = randi([0 1], 20); % Generating values 0 and 1 on that grid
x1 = randi(20, 20); % generating random locations of x on grid for interplotation
y1 = randi(20, 20); % generating random locations of y on grid for interplotation
z1 = interp2(x, y, z, x1, y1); % getting values of z by interplotation on those random locations

I hope it helps understanding the concept. Good luck!