MATLAB: How to do density scatter plot

densityscatter plot

I have a cubic box with the size of, lets say 300 in each direction. I have some data (contains X,Y,Z coordinates) which represent the distribution of nearly 1 million data-points within this box. I want to specify a color to their Number density (its an intensive quantity used to describe the degree of concentration of countable objects in this case data-points). In another word, Using color to illustrate which part is more condensed in terms of data-points rather than the other parts. The index for the color-bar in the final image should represent the percentage of data-points specified with that color.
I have tried to do it by dividing the whole space in cubic box to 1 million smaller cube (each cube has a length of 3 in all direction). By counting the number of particles within those cube, I will know how they distributed in the box and the number of existed data-points within. Then I can specify a color to them which I wasn’t successful in counting and specifying. Any suggestion is appreciated.
%reading the files
[FileName,PathName,FilterIndex] = uigetfile('H:\*.txt','MultiSelect','on');
numfiles = size(FileName,2);
j=1;
X=linspace(0,300,100);
for ii = 1:numfiles
    FileName{ii}
    entirefile = fullfile(PathName,FileName{ii});
    a = importdata(entirefile);
    x = a(:,2);
    y = a(:,3);
    z = a(:,4);
    for jj = 2:size(X,2) % loop over all points
        if x(:)<X(jj) & y(:)<X(jj) & z(:)<X(jj)
           x;
        end
    end
    h=figure(j);
    scatter3(x, y, z, 'filled', 'MarkerSize', 20);
    cb = colorbar();
    cb.Label.String = 'density estimate';
end
I need to get a similar result like the following image. but I need the percentage of data-point specified by each color. Thanks in advance.

Best Answer

1Untitled.png
C = x*0;
for i = 1:length(x)
    v = (abs(x-x(i)) < R) & (abs(y-y(i)) < R) & (abs(z-z(i)) < R);    % how many points in cube
%     v = (x-x(i)).^2 + (y-y(i)).^2 + (z-z(i)).^2 < R^2;        % or sphere
    C(i) = sum(v)-1;                                          % number of points except x(i)
end
scatter3(x,y,z,10,C)
You can also visualize your data with contourslice()
Related Question