Help with 3d matrix

Hi, I'm learning to use matlab, and I have a problem, I've been trying to do a matrix 3d with the next sizes: X and Y which are 76x88, and and Z is 24x1. And I did:

[x,y]=meshgrid(X,Y); 
[x,y,z]=griddata(X,Y,Z,x,y)

But.... x and y returns like 6688x6688, and the griddata gives me a error in the sizes from de matrices... what can I do ?

Answer 1

[Walter Roberson]

You are using the griddata form matching https://www.mathworks.com/help/matlab/ref/griddata.html

vq = griddata(x,y,v,xq,yq)

For that syntax, x, y, and v need to be vectors.

Your equivalent to v, Z in your code, is a vector of length 24 x 1, which is fine in itself.

Your x and y start out at 76 x 88 . Neither of those are vectors. They also are not multiples of length 24 (your Z). Your x and y need to be the same length as your z.

Now, if you had an x which was 76 x 88, and a y which was 76 x 88, and a z the same size, then you could

griddata(x(:), y(:), z(:), xq, yq)

for some xq, yq

Your variables give the impression that you have data for a single X/Y plane, and you have a vector of Z values that you want to make predictions at. That is not going to work: you (x, y, z) triples as input to make predictions against.