CODEWITHSUNDEEP
matlabif-statementhistogram
energyMax
energyMax

Reputation: 419

3D histogram and conditional coloring

I have a series of ordered points (X, Y, Z) and I want to plot a 3D histogram, any suggestions?

I'm trying to do it by this tutorial http://www.mathworks.com/help/stats/hist3.html , but points are random here and presented as a function. My example is easier, since i already know the points.

Furthermore, depending on the number value of Z coordinate, i'd like to colour it differently. E.g. Max value - green, min value - red. Similar as in this case Conditional coloring of histogram graph in MATLAB, only in 3D.

So, if I have a series of points:

X = [32 64 32 12 56 76 65]
Y = [160 80 70 48 90 80 70]
Z = [80 70 90 20 45 60 12]

Can you help me with the code for 3D histogram with conditional coloring?

So far the code looks like this:

X = [32 64 32 12 56 76 65];
Y= [160 80 70 48 90 80 70];
Z= [80 70 90 20 45 60 12];
A = full( sparse(X',Y',Z'));
figure; 
h = bar3(A); % get handle to graphics
for k=1:numel(h), 
    z=get(h(k),'ZData'); % old data - need for its NaN pattern
    nn = isnan(z); 
    nz = kron( A(:,k),ones(6,4) ); % map color to height 6 faces per data point 
    nz(nn) = NaN; % used saved NaN pattern for transparent faces 
    set(h(k),'CData', nz); % set the new colors
end
colorbar;

Now I just have to clear the lines and design the chart to make it look useful. But how would it be possible to make a bar3 without the entire mesh on 0 level?

Upvotes: 3

Views: 313

Answers (1)

Dan
Dan

Reputation: 45752

Based on this answer, all you need to do is rearrange your data to match the Z format of that answer. After than you might need to remove edgelines and possibly clear the zero height bars.

% Step 1: rearrange your data
X = [32 64 32 12 56 76 65];
Y= [160 80 70 48 90 80 70];
Z= [80 70 90 20 45 60 12];
A = full( sparse(X',Y',Z'));

% Step 2: Use the code from the link to plot the 3D histogram
figure; 
h = bar3(A); % get handle to graphics

set(h,'edgecolor','none'); % Hopefully this will remove the lines (from https://www.mathworks.com/matlabcentral/newsreader/view_thread/281581)

for k=1:numel(h), 
    z=get(h(k),'ZData'); % old data - need for its NaN pattern
    nn = isnan(z); 
    nz = kron( A(:,k),ones(6,4) ); % map color to height 6 faces per data point 
    nz(nn) = NaN; % used saved NaN pattern for transparent faces 

    nz(nz==0) = NaN; % This bit makes all the zero height bars have no colour

    set(h(k),'CData', nz); % set the new colors. Note in later versions you can do h(k).CData = nz
end

colorbar;

enter image description here

Upvotes: 2

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