Scatter problem3
This is probably scatter3
what I don't understand. I have a matrix from which all slices but the last are NaNed ( M(:,:,1:10) = NaN;
) and then it moved the first and last dimension. Thus, M(11,:,:)
there are only meanings in. I expect all plotted values to be in the YZ plane at a point x==11
, but the graph looks different (see code and picture below). Any explanations?
M = rand(22,55,11);
M(:,:,1:10) = NaN;
M = permute(M,[3 2 1]);
shape = size(M)
[x, y, z] = meshgrid(1:shape(1), 1:shape(2), 1:shape(3));
scatter3(x(:), y(:), z(:), 4, M(:), 'fill');
view([60 60]);
xlabel('X ', 'FontSize', 16);
ylabel('Y ', 'FontSize', 16);
zlabel('Z ', 'FontSize', 16);
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Explained what meshgrid
toggles x and y:
From the meshgrid
documentation:
MESHGRID is similar to NDGRID, except that the order of the first two input and output arguments are toggled (ie, [X, Y, Z] = MESHGRID (x, y, z) gives the same result as [Y, X , Z] = NDGRID (y, x, z)).
At first glance, this should result in a plot with values in the XZ plane at y == 11 (i.e. x and y are swapped compared to what you originally expected). But note that your code does not handle x and y correctly (because of meshgrid
). This has the additional effect that the coordinates x
and y
"shuffled," and you do not see the plane (even in the XZ), but rather a lattice.
So the solution is to use ndgrid
that doesn't perform any switches. Just replace " meshgrid
" with " ndgrid
" in your code. The resulting figure is now as expected:
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