Question

I have function which plots some 3D figure with

scatter3(mx,my,mz,3,mx.^2+my.^2); % mx, my and mz are vectors

I see that C is a vector the same length as X and Y, so color of each point should be linearly mapped to the colors in the current colormap, per documentation.

I tried this:

cmap = colormap;
disp(cmap(mx.^2+my.^2));

but I am getting

Subscript indices must either be real positive integers or logicals.

Is there any easier way to solve this quest?

Thanks

Answer 1

That’s rather easy. Colormap does not return a vector, but a matrix. This is because each colour has three components (red, green and blue).

>> size(colormap)

ans =

    64     3

>> test = colormap;
>> test(7, :)

ans =

     0         0    0.9375

EDIT … And, I forgot something: The indices need to be integers, in one way or another. You may like to round them or turn them into an integer.

EDIT2 … According to your example, the disp-statement works like this:

disp( cmap(1:( (size(cmap, 1)-1) / (length(mz)-1) ):size(cmap, 1), :) );