3D array permutation

I have a 3D volume mask_GTV (256x256x137) and I want to plot 3 different slices: XY,YZ,XZ.

Currently I use permute [1 3 2] for the XZ plane for example.

G = permute(mask_GTV,[1 3 2));
contour(G(:,:,120),[.5 .5])

The dimensions in this plot are different from what I expect. I would expect this to be a 256x137 plot, but it is 137x256.

How can I plot the correct slice?

Answer 1

[James Tursa]

According to the doc for contour(Z), "... The x values correspond to the column indices of Z and the y values correspond to the row indices of Z ..."

So if you want the other order, do a different permute to account for it. E.g.,

G = permute(mask_GTV,[3 1 2));

Answer 2

[Anton Semechko]

Suppose you have G, which is a Y-by-X-by-Z 3D array, then

i-th xy slice:

G_yx=G(:,:,i); % Y-by-X array

i-th xz slice:

G_xz=permute(G(i,:,:),[2 3 1]); % X-by-Z array

i-th yz slice:

G_yz=permute(G(:,i,:),[1 3 2]); % Y-by-Z array