Plot matrix as scatter points with colorbar

Dear all

I have a vector 1-by-N x, a vector 1-by-M y, and a matrix N-by-M z (complex).

So how could I plot the matrix Z as scatter points corresponding to x and y, where the colorbar represents the abs(z). I have tried scatter3 but it only works when z is a vector, not a matrix. Thanks

Answer 1

[Star Strider]

One approach is to use meshgrid to create matrices out of ‘x’ and ‘y’, then plot all of them as vectors, using the (:) subscript notation to force them all to become column vectors:

N = 5;
M = 8;
x = 1:N;
y = 1:M;
[X,Y] = meshgrid(x,y);

z = randn(N,M) + 1j*randn(N,M);

figure
scatter3(X(:), Y(:), abs(z(:)), 25, abs(z(:)), 'filled', 'Marker','p')
colormap(jet(numel(z)))
colorbar

Experiment to get the result you want.

[Shan Chu]

Thank you sir. I didn't know the trick (:) to force them to all become column vectors. Brilliant

[Star Strider]

As always, my pleasure.

Thank you.

Using the reshape function also would work. The (:) notation is easier and more efficient.