how to form rectangular matrix of x, y, z in (:,:,3) format from circular data

I have data of D(:,:,3) format where x= 5*sin(theta)cos(phi), y=5*sin(theta)sin(phi) and z some data related to this points where theta= 0-pi/2 and phi = 0-2 pi. how can i rearrange the data of z in to [X,Y]=ndgrid(x,y) for x=linspace(-t,t,n) , y=linspace(-t,t,n) format?

[Guillaume]

Can you clarify what each dimension of D represent (is it D(y, x, z) and what the values of D represent?

[Dhelp]

let D is (100, 100, 3) matrix and D(:,:,1) is x , D(:,:,2) is y , D(:,:,3) is z component ...

[Guillaume]

That's what I understood initially, but then I don't understand what the first two dimensions of D represent. I would have thought that D would be a P x 3 matrix, with P the numbers of points.

[Dhelp]

let phi = 0, theta = 0:pi/100:2*pi, so we have a matrix (1,100) so for each phi until pi/2 , lets say we have (100,100) matrix , and since x, y, z have different formula we have D(100,100, 3) but this data is not sorted in x or y incremental way , so what i need is to make the matrix in an incremental grid format lets say X=[-5:5], Y=[-5 5]

[Titus Edelhofer]

Hi,

please take a look at the answer below: if you have e.g. x=-5:0.5:5, y=-5:0.5:5, then create matrices X, Y with

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

Use these matrices as points xi, yi when calling griddata.

Titus

Answer 1

[Titus Edelhofer]

Hi,

if I understand correctly you have a set of points which are given on 3D spheres and want to have them on a regular (cartesian) grid. If this is the case, then you are looking for the function

griddata

You construct the grid using meshgrid or ndgrid and use griddata to interpolate your points onto this grid.

Titus

[Dhelp]

Thank you