Question

I’m trying to plot scatter, something like:

scatter(coor(:, 2), coor(:, 3), 1, coor(:, 4));

The problem is, that I have quite big number of coordinates to plot (~100 000). Its taking long time to plot it, and when I try to export figure to tiff – then matlab is dead for goooood few minutes… Any solution to improve plotting, or at least tiff export?

EDIT:
Forgot to mention, 3rd coordinate (coor(:, 4)) is a color code.

So, when I’m using scatter (as above), I have something like on the image below, and thats exactly how I want to see it (just its super slow and I can’t export that):

When I do:

plot3(coor(:, 2), coor(:, 3), coor(:, 4), ‘.’)

effect is not as cool any more (note: images are not from the same coordinates…) :

Answer 1

You can use plot, but then all points have the same color. However, you can divide the set in different subsets and plot them each with their own color:

N = 100000;
x = rand(N,1);
y = rand(N,1);
C = sin(2*x)+y;

cdivs = 10;
[~, edges] = hist(C,cdivs-1);
edges = [-Inf edges Inf]; % to include all points
[Nk, bink] = histc(C,edges);

figure;
hold on;
cmap = jet(cdivs);
for ii=1:cdivs
    idx = bink==ii;
    plot(x(idx),y(idx),'.','MarkerSize',4,'Color',cmap(ii,:));
end

colormap(cmap)
caxis([min(C) max(C)])
colorbar

which responds already a lot better than scatter(x,y,1,C) which gives about the same plot, but with higher color resolution (which is adjustable in my code above).